Category Archives: Firearms Building and Gunsmithing

How to build and/or gunsmith on certain platforms.

POF, PTR, Roller Locks - HK, Zenith

We Now Have Contour, Navy SEF and Magpul SL Grips For HK MP5K Weapons and Clones

It’s taken a while to work out the processes and tooling but now we have a variety of grips converted for HK MP5K weapons and their clones including:

  • Century / MKE AP5-P and AP5-M pistols
  • HK MP5K, SP5K – for the SP5K, slight trimming of the front locking plate on the grip will be required
  • POF 5PK
  • PTR 9KT
  • Zenith ZF5-P, ZF5-T, and ZF5-K

There are three required features for these to fit:

  1. It must be an MP5K pattern weapon and not an MP5 or other variety of roller lock.
  2. It must have an HK MP5K patterned top rear hole.
  3. It must have a front shelf that the grip’s front locking plate rests on.

Technically, our Contract Contour and Navy SEF grips do support the front lower pin that some MP5Ks use. However, our converted Magpul SL grip does not have a front lower pin and does not need it because it is pushed forward against the weapon’s shelf and can’t slide out of position.

How They Are Made

Interestingly enough HK33, HK91/G3, HK93, HK94, MP5, and MP5K grips all have the same size polymer core grip albeit with different metal “tails” sticking out of the rear to accomodate whatever weapon they are meant for. Now there may be other models out there as well – but those are the ones that I know of so far.

This is a used HK G3/91 Navy SEF grip. The core black polymer shape is the same size as what we need for an MP5K.

The first step if you have one of these model grips is to removed the “tail” so the length will be correct for a MP5K, I would recommend cutting off the tail and then deburring it. Do not remove any polymer so you can get a firm fit when you install whatever stock, brace or end cap you plan to use.

This is a new HK 91/G3 Navy SEF grip with the tail cut off. I use a bandsaw to cut them with a fine tooth blade.

Measure the Existing Rear Hole Centers and Countersink Depths

To cut the rear holes is a bit more involved. First, you need to locate the centers of your existing MP5K grip’s rear holes. I’d recommend using quality calipers but you can do whatever you are comfortable with as long as the method is relatively accurate.

I would also recommend you measure from the front of the steel plate inside the front of the grip back to the center of the hole on your existing grip. That gives you the horizontal distance. To get the vertical distance, measure down from the top.

Measure from the front of this plate (the surface facing you in this photo) back to the center of the hole.

You should measure this on both sides of the grip. You may find they are not exactly the same. Regardless, double and triple check the horizontal and vertical measures on both sides.

The other measurement you need to find out is how deep to drill the countersink hole – the recession in the grip where the head sits on the left side (looking down) and the end with the wire retainer protrudes on the right. You may well find that the two measures are different again.

What you need to ensure is that the rear takedown pin’s working distance can span from the left side to the right side. The working distance of a takedown pin is the measured length from just under the head to just before the retaining wire comes out of it. The pin that sticks out of the other end of your calpers is for measuring depth. There are also far more accurate tools purpose-built for measuring depth also.

When you do you plan your countersinks, you need the distance the pin spans to look something like this:

Minimum depth of countersink = outside grip dimension – takedown pin working length

Now how you make that happen is up to you. For example, if you need to remove 3mm and want to split it to 1.5-1.6mm per side – that’s fine. Ideally, you want the pin to stick out far enough on the right side so the wire retainer can pop up and help hold the pin in place.

Milling the Countersink & Pin Holes

These operations require end mills that can make plunge cuts – meaning the end mil has cutting surfaces at the bottom and not just the sides. These are sometimes called “center cutting” end mills also. I would also recommend four flutes for a smooth finish.

The actual countersink diameter is 9.5mm but if you don’t have access to that, a 10mm end mill will work also. The takedown pin hole is 6mm. How much you want to spend on the quality of the mills is up to you. The polymer will not wear the 9.5-10mm bit much but the 6mm bit will need to keep its edge long enought to cut through the steel reinforcement on both sides. I’d recommend the6mm be either cobalt or carbide and not just high speed steel – or at least not cheap high speed steel.

Milling the 10mm countersink. My mill has a Digital Read Out (DRO) so I know how deep to go.

If you are wondering why not use a 6mm drill bit, it is because you will likely encounter a hole in the reinforcing plate that was cast into the grip during injection molding. A drill bit will hit that hole and want to yank the workpiece upwards as the edge of the opened hole rides up the flute and makes a mess. An end mill doing a plunge cut will not have this problem as it will cut off the open circle’s ends.

That slightly offset circle is exposed when you do the countersink. A drill bit will cut open the circle and then the grip will want to ridge the bit up.

So, yes, you can use a drill press but what is incredibly important is that you have the workpiece held firmly so you need to clamp it down.

Make a wood or plastic insert that you can put in the top of the grip to keep it from deforming when clamped and then milledd/drilled. If the grip moves at all, your new grip will be ruined.

Honestly, 99% of my challenge was figuring out how to securely hold the grips so they wouldn’t move and also not introduce angles/canting, etc. I’m still working on improving this as the overwhelming amount of my defects are caused by unintended workpiece movement.

You need to locate your new hole centers and then set up your milling machine or drill press to do the cuts. You need to figure out what works best for you. If you have digital read outs (DROs) then you probably didn’t need to read this blog post. If you are new to this, locate the hole center and mark the hole with a very fine point then use either a small drill bit or hole finder to center your machine on the hole.

To get the depth you need on the countersink, either use the features of your machine if it has some form of depth indicator or wrap a piece of tape at whatever limit you need and stop when you reach it.

I would highly recommend you do the countersink cut and then the hole cut on each side before you move on to the next. In other words, do a side at a time before you move the workpiece.

If you are wondering why I am not mentioning how to locate and cut the front pin holes, it’s because you don’t really need them if your weapon uses a shelf, which most current HK grips do. For example, the Magpul SL grip does not have the front holes. The way the polymer is formed, you would likely need a longer pin and it’s not going to give you a better connection. The front plate of the grip is shoved against the shelf by whatever you have on the end of the weapon and the top rear pin keeps the grip from swinging down – that’s really all that you need.

Here is a batch of converted “good condition” real HK Navy SEF grips getting ready to go to their new owners. We do repair any minor gouges and apply a restorative finish to make them look good. That’s the original HK paint by the way. Click here if you are interested.

Summary

You can do the conversion or buy our ready to go grips. You may need to do some final fitting but we’ve done the hard parts. If you’re interested, click here to go to our HK Grips page.

I hope this helps you out,

If you find this post useful, please share the link on Facebook, with your friends, etc. Your support is much appreciated and if you have any feedback, please email me at in**@ro*********.com . Please note that for links to other websites, I may be paid via an affiliate program such as Avantlink, Impact, Amazon and eBay.

Firearms Building and Gunsmithing, Sniper / Precision Rifles

Adding a Minimalist Spigot to a KRG Bravo Chassis

In my last post, I mentioned my disappointment that the Kinetic Research Group (KRG) Bravo chassis that Aero Precision sells with some of their Solus bolt rifle offerings is not truly bipod ready. In my opinion, Aero should either have discosed that the stock isn’t bipod ready and/or given an option during the purchase of the Solus to buy one of the models of spigots that KRG offers. Okay, that’s water under the bridge. I want to make this post about adding a spigot to a Bravo.

First off, sincere kudos to KRG for a really nicely done modular and extensible chassis that looks like a stock. It’s very well designed and executed. The Bravo has tons of ways you can configure it. Some are included such as the adjustable cheek piece, length of pull and one rail segment. Others you need to purchase such as forward mounts for night vision devices, ARCA Swiss mounting accessories and far more. One of the accessories you can buy are various spigots.

It’s time for me to explain what I am talking about – a spigot is an attachment point that extends forward past the front end of the stock where a bipod, and sometimes other accessories, can be attached.

In the case of the Bravo, a spigot will connect to the aluminum chassis and both move the bipod mounting point forward and provide an extremely secure mount directly to the chassis.

Nostalgia Time

The first time I encountered a spigot was with Versa-Pod bipods. It’s been so long, I can’t recall if I found out about Versa-Pods and then bought an Accuracy International Chassis System (AICS) for my Remington 700 XCR LR or it was the other way arround.

You can see the spigot sticking out of the front of the AICS – in this case it is an adapter to use a Versa-pod bipod.

I don’t really recall when but at some point I moved away from the Versa-Pods mainly because I didn’t like the rotation around the spigot unless you really cranked down the locking knob. These days, my go-to bipods are Atlas models.

Back to KRG Spigots

KRG literally has a whole page of different spigots. There really are three factors that distinguish them – whether it is an ARCA pattern, how far forward you want the mounting point and what all you want to attach.

I’ll be honest – I actually had to call KRG to figure out what I needed. The customer service person I talked to was great and patiently explained the pros and cons of each based on what I needed:

  • I did not need to connect an ARCA device, such as a tripod. Since I did not need ARCA this also ruled out their really long spigot.
  • I only needed a bipod mount. Their normal spigot provides all kinds of attachments for rails, QD studs, night vision, etc.

Ok, no ARCA and just a bipod. That pointed me to the Minimalist spigot. The Minimalist moves the mount closer to the bore – which means you can get lower all things being equal. It also moves the attachment about five inches forward.

One thing with the Minimalist – it does not come with a rail section. You can either use the polymer one that came with your stock or buy an aluminum section from them. There rails sit flat as they not have the typical M-Lok boss on the back. This also means you can’t use a common M-Lok rail.

Your other option is to bolt an Atlas bipod or a Harris bipod they sell directly to the spigot. I like using a rail because I can pair it with an American Defense Manufacturing (ADM) quick release lever and have the ability to quickly take the bipod off if I don’t need it. For example, if I am shooting from a bench rest.

How to install the Minimalist spigot

If you can turn a screwdriver, you can install the spigot has there are just a few steps:

  1. Remove the bottom chassis cover by removing eight bolts
  2. Screw the spigot into place – use blue/medium thread locker on the bolts
  3. Apple blue/medium strength threadlocker to each bolt and screw the rail segment onto the spigot – assuming you go that route
  4. Apply blue/medium strenth thread locker to each bolt and screw the bottom cover back on

It’s nice when something literally is that easy.

Remove the 8 screws that hold the cover on the chassis’ backbone. Note, the rear two are longer than the others.
The spigot will screw on in the front.
This is the Minimalist spigot that bolts right into place.
The machining is very well done. The holes all line up and it’s just a matter of screwing it together.
Apply medium strength thread locker to the screws they provide. Note the holes used above. The forward outermost holes in this photo are used to secure the cover.
In my case, I screwed in the rail section after applying medium strength thread locker to the screws.
Apply blue/medium strength threadlocker to the screws and install them. This is a polymer cover you are installing and do not need a lot of torque.. Bring it down snug/firm and let the threadlocker do its job.
This is an Atlas BT65-LS17 bipod. The BT65s are great rigid bipods that don’t pan left and right. It uses an ADM LS17 quick release clamp to secure quickly to rails. If I had wanted it, I could have ordered the BT65 without the clamp and installed it directly to the spigot. Due to all of the counterfiet Atlas bipods that are out there, I buy mine directly from AccuShot. I’d recommend you do that or buy them from a reputable dealer. Avoid buying an Atlas model from eBay like the plague.
The result is incredibly solid. If I had known how nice this setup was, I would have paid for it from the start.
The ADM LS-17 quick release clamp does a great job holding the Atlas BT65 solidly in place.
Here’s a view of the whole Solus Bravo .308 with the spigot and Atlas BT65-LS17 bipod.

Summary

Okay, I was starting to like the Bravo chasis more and more. The Minimalist spigot is absolutely worth it. You can then either mount your bipod directly or via a Picatinny rail section like I did.

Dear Aero – hint, hint – I would have paid for the spigot in a heartbeat had I known how solid it is and what a stable platform it can enable.

To anyone reading this who has a Bravo chasis – adding a spigot is very much worth it. I’m honestly glad I did.

I hope this helps you out.

Note, I have to buy all of my parts – nothing here was paid for by sponsors, etc. I do make a small amount if you click on an ad and buy something but that is it. You’re getting my real opinion on stuff.

If you find this post useful, please share the link on Facebook, with your friends, etc. Your support is much appreciated and if you have any feedback, please email me at in**@ro*********.com . Please note that for links to other websites, I may be paid via an affiliate program such as Avantlink, Impact, Amazon and eBay.

Glock, Glocks, Gunsmithing, Polymer80, Shooting in General, Uncategorized

Glock Truglo Tritium and Fiber Optic Sights Are Amazing Improvements!

A fellow emailed me wanting to upgrade his from the generic OEM Glock sights that I don’t think really excite anyone to something that would be more visible in general and also work in the dark. My answer was immediate – go with the TRUGLO TFX Pro Tritium and Fiber Optic Xtreme sights.

The featured photo above shows how bright they are on my G17 slide on it. I bought these sights by the way – so you are getting my honest opinion.

Folks, these are my hands down favorite sights for a number of reasons:

  • They are CNC machined from steel and have a durable black nitride finish — they are not soft plastic.
  • They do not need batteries – the lit dots are via fiber optics when there is light and sealed tritium when it is dark so you are covered regardless of the light available. The tritium ought to fluoresce (emit light) for about 10-20 years and I’ll worry about replacing them then.
  • I really like the three green dot configuration – two on the rear sight and one on the front. The front also has an orange ring that you can see when there is light but is green when operating off the tritium only.
  • The rear sight goes into the slide’s groove very easily and is then secured with a set screw. Some sights can be a bear to install but not these.
  • The rear sight is big enough that it can help you rack the slide one handed in a one-handed emergency.
  • They have a 12 year warranty.
  • They are assembled in the USA – the tritium capsules are made in Switzerland.

What Glock models are supported?

Because these are so popular TRUGLO is making a variety of models to support the different Glock configurations that are out there. I assembled the following table and you can also check their webpage if you want:

TG13GL1PCGlock® 17 / 17L, 19, 22, 23, 24, 26, 27, 33, 34, 35, 38, 39, 45 (Excluding M.O.S. models)
TG13GL2PCGlock® 20, 21, 25, 28, 29, 30, 31, 32, 37, 40, and 41 (Excluding M.O.S. models)
TG13GLAPC
(TFX front, Adjustable Rear)		Glock® 17 / 17L, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 38, 39, 41, 45 (Excluding M.O.S. models)
TG13GL3PCGlock® 42, 43, 43x, 48; Honor Defense® (all models)
Source: https://truglo.com/spare-quiver-mount-spare-quiver-mount

Personally, I use the TG13GL1PC on a G17 and G34. I bought both off sight sets off Amazon – click here to see the large selection there.

This gives you a better view of the sights overall. This is the TFX Pro TG13GL1PC with the fixed rear sight. I really like the sight picture these give day or night.
Here’s the rear sight and you can just barely see the set screw that secures the sight between the two “ears”. The slot at the top of each fiber optic is where it collects light to illuminate the dot. If there isn’t any light then that is where the tritium capsules take over.
Here’s the front sight. The orange ring is nice during the day and you only see the green tritium dot in the dark.
Well, trying to take a photo in the dark of three green dots with a cell phone camera was an experience. I went in a basement room and shut the door to cut off light. It’s fuzzy but you get the idea – all three dots are nicely lit in any lighting condition.

Do they have lower cost models also?

Yes, they do. The Tritium series just has the tritium for illumination in the dark and show as bright white dots during the day.

TG231G1Glock® 17 / 17L, 19, 22, 23, 24, 26, 27, 33, 34, 35, 38, and 39 (Excluding M.O.S. models)
TG231G2Glock® 20, 21, 25, 28, 29, 30, 31, 32, 37, 40, and 41(Excluding M.O.S. models)
TG231G1AGlock® 42, 43
Source: https://truglo.com/catalog/product/view/id/2068/s/tritium-tritium/category/19/

They also make a Tritium Pro series that builds on the Tritium base model and adds an orange ring to the front sight plus the back sight is bigger and that makes it easier if you need to rack the slide with one hand.

TG231G1WGlock® 17 / 17L, 19, 22, 23, 24, 26, 27, 33, 34, 35, 38, and 39 (Excluding M.O.S. models)
TG231G2WGlock® 20, 21, 25, 28, 29, 30, 31, 32, 37, 40, and 41(Excluding M.O.S. models)
TG231G1AWGlock® 42, 43
TG231G1MWGlock® MOS 17, 19, 22, 23, 24, 26, 27, 33, 34, 35, 38 and 39
TG231G2MWGlock® MOS 20, 21, 25, 28, 29, 30, 31, 32, 37, 40 and 41
Source: https://truglo.com/catalog/product/view/id/2069/s/tritium-pro-tritium-pro/category/19/

Do they support other brands and models of pistols?

Definitely. These are very popular lights given their great combination of quality at a fair price. I tend to see the best prices on Amazon – click here to see them.

Conclusion

I find these sights to be an incredible improvement over the plain Glock sights – they are easy to see and aid with rapid aiming. I really do like these sights and use them personally. I strongly recommend them.

I hope this helps you out.

Note, I have to buy all of my parts – nothing here was paid for by sponsors, etc. I do make a small amount if you click on an ad and buy something but that is it. You’re getting my real opinion on stuff.

If you find this post useful, please share the link on Facebook, with your friends, etc. Your support is much appreciated and if you have any feedback, please email me at in**@ro*********.com . Please note that for links to other websites, I may be paid via an affiliate program such as Avantlink, Impact, Amazon and eBay.

Roller Locks - HK

Why grips converted for MP5Ks have a weirdly shaped rear pin hole

Grips for the MP5/HK33 and HK91/G3 rifles can be converted for use on MP5K-type weapons. As you can see in the photo above, a small circle appears at about 2:30 position on the larger hole for the pin when this is done. I used to wonder why and since I started offering converted grips for sale, I’ve had a few guys also ask me why this is the case.

Well, the short answer is that the steel reinforcing that is cast into the rear of the grip has different holes when an MP5K grip is made vs. the others. This allows the hole for the pin and the countersink for the head to not encounter another hole.

This is a real German H&K MP5K grip. The top rear hole doesn’t have that telltale circle of conversion because it was purpose built to be mounted on a MP5K.
Not one of my better photos but you can see the pin hole on the far side. The anchor holes to secure the metal strap are to the left and right of it are filled in with plastic during injection molding. Notably at the rear right there are two anchor holes to help compensate and secure the strap.

With the MP5/HK33 and HK91/G3 grips, the designers never planned for a hole to be made in that location and as a result, the newly drilled hole runs right into an anchor hole they have in the metal to allow the injection molding to adequate bond to it.

If you try to drill into one of these grips, the smaller hole will get cut open and then ride the flute of the drill upwards and make a mess. To compensate for this, an end mill must be used to do a plunge cut straight down. There must be careful workholding fixtures to keep the grip from moving. Trust me, I’ve trashed a bunch of grips by not making sure the grip was completely secure.

This HK33 contract grip has anchor holes that go evenly across. There isn’t enough spacing between those holes for a new 6mm pin hole and 9.5mm countersink to be milled without hitting the rear anchor hole.
This is a Malaysian contract grip has the rear steel “tail” has been cut off. Both pin holes and countersinks have been drilled. Look at the hole on the right. The pin hole ran right into the anchor hole and tore out the plastic that would have filled it. By the way, the orange paint was from me tracking early prototypes. It’s not something someone would normally see.

Despite those rear anchor holes being removed, the steel reinforcing is still held in place. While theoretically weaker, I have not heard of any real world cases where the the steel (it’s folded sheet metal really) has come lose due to separation from the surrounding polymer.

For people using converted grips, just insert your rear pin such that the retaining wire is on the shoulder and not in the hole. That’s really the only difference. Of course, like most grips, some final fitting may be required – by using a circular file to adjust the rear hole, filing the front locking plate or removing a bit of material off the back with a file or by sanding.

Summary

In short, purpose built MP5K grips have enough spacing between the rear metal strap’s anchor holes for the 6mm pin hole and 9.5mm countersink to be drilled. Other HK models do not use that same spacing so the tell tale partial hole appears at the 2:30 position. It’s purely cosmetic and just requires the user to insert the rear pin such that the locking wire rests on the normal shoulder of the hole and not the newly formed void.

I hope this helps you out.

If you are interested, our online store has a number of HK grips available – both converted and not. Click here.

If you find this post useful, please share the link on Facebook, with your friends, etc. Your support is much appreciated and if you have any feedback, please email me at in**@ro*********.com . Please note that for links to other websites, I may be paid via an affiliate program such as Avantlink, Impact, Amazon and eBay.

Gunsmithing, Roller Locks - HK, Shooting in General

Reviving Old Black Plastic HK Grips – Or Just About Any Other Faded Plastic

Do you have an old HK grip, or any other plastic item, you want to rejuvenate? Or maybe you bought one of the contract grips, washed it and now it’s a dull grey and all of the scratches stand out and you want to make it look better?  It’s easier than you might think.

Clean the grip

I recently boought a bunch of the the surplus HK33 “contract grips” that were made by SME Arms and Ordnance manufacturer, Malaysia under license from HK and most of them really needed cleaning – everything from cosmoline to brown masking tape with numbers were on them.

The first thing is to really clean the grip.  I use a Vevor 30L ultrasonic cleaner [click here for a review I did on mine] with Simple Green HD and water in it but you can use any warm-to-hot soapy water and something to scrub with to clean it up.  Use compressed air to blow it dry real quick before any exposed steel surfaces rust.

These HK33 grips are a mess. Most are beaten up to some extent. Many were covered in cosmoline – that grip on the top that is shiny is coated in it. Some even had old dry masking tape wrapped around the actual hand-grip portion.

For cleaning, I use an ultrasonic cleaner. I have a 30 Liter Vevor and it’s great. Vevor offer all kinds of sizes – if you are interested, click here for a blog post I did about mine. You can calso click here to see the current listings on Amazon.

If you aren’t interested in ultrasonic cleaners, you can also have very good luck with hot soapy water. I used to recommend brake cleaner but that has really lost its cleaning power as various regulations have really reduced its strength.

This is a 30 liter Vevor ultrasonic cleaner filled with Simple Green Pro HD heated to 158F (70C). It gets rid of pretty much everything in 15 minutes including most if not all of the paint in the lettering.

Dealing with scratches and small nicks

Major repairs can be a challenge. Filling them with black epoxy or black super glue creates visible repairs. Black super glue to close a clean crack works surprisingly well. Starbond makes a black super glue that is superb at closing cracks plus bonding clean surfaces together in general – click here to see it at Amazon

For minor scrapes and scratches, the best approach I have found is to use 0000 (sometimes called “quadruple ought” or super fine) steel wool and vigorously rub down surfaces to get rid of scratches and any plastic sticking up from getting nicked. The benefit I have found with it vs. sandpaper is that it doesn’t destroy the surface finish as easily.

This is an actual HK German SEF grip converted for use on an MP5K. I used 0000 steel wool to knock over any sticking out plastic and reduce minor scratches. I find careful use of steel wool helps me improve the surface some without destroying the pebbled finish on the plastic.

Restoring the black color

Black plastic fades as the surface layer loses its oil/moisturizers.  The trick to try and replace those lost chemicals and bring the color back.

Black plastic that has been ultrasonically cleaned is greyish and you can see all of the scratches. If you don’t know it’s coming you can have a “what just happened” moment.

The treatment I use is made by Car Guys and is called “Plastic Restorer”.  Again, make sure the grip is clean and then rub this stuff in.  I use nitrile gloves and work it in.  You want a thin film there.  I let the stuff sit overnight and buff it off with a shop towel the next day.  It does a nice job and will last for sometime.  I’m not exactly sure how long – I’ve been using it for almost six months and nothing has faded yet.

On this HK SEF grip, it’s been cleaned and I used steel wool to knock down any rough spots. Next up is applying Car Guys Plastic Restorer.
The actual cream that comes out is an odd blue grey color. I wear nitrile gloves, put the cream in my glove and then apply enough to leave a film.
It does need to have a light film – not super thick but something like this.
It has to sit to work, I try to let it sit overnight if I can. They say at least 10 minutes but I find the longer the better. You then wipe it down and remove any residue on the surface,
This is the same grip. It sat overnight and then I wiped it down the following day.
Same grip – other side.
These are four of the grey ashen grips shows above after following this process.
Same grips – the other side.

Summary

I did not know why black colored platics fade with time. Now I do and the Car Guys Plastic Restorer works on more colors than just black. Click here for it on Amazon – there’s a reason there are over 31,000 reviews and a score of 4.4. It’s that good. So, whether it’s plastic on firearms, cars or something else, this stuff might really help you bring the color back.

One perk is that it does seal and provide UV protection after it is applied. I’ve been using it for six months and nothing has faded yet but then again, no finish lasts forever so I would bet that some day I will need to touch things up.

Note: This stuff isn’t for headlights and it doesn’t fix physically damaged plastic when there is a thick crust of oxidation or scratches. It’s meant to bring the color back is all.

I hope this helps you out.

Note, I have to buy all of my parts – nothing here was paid for by sponsors, etc. I do make a small amount if you click on an ad and buy something but that is it. You’re getting my real opinion on stuff.

If you find this post useful, please share the link on Facebook, with your friends, etc. Your support is much appreciated and if you have any feedback, please email me at in**@ro*********.com . Please note that for links to other websites, I may be paid via an affiliate program such as Avantlink, Impact, Amazon and eBay.

Roller Locks - HK

How to Convert a Magpul SL Grip For Use On A MP5K

There are some things I like on MP5Ks and some things I don’t.  I usually dislike the triggers but my MKE AP5-P has a fairly decent trigger as MP5 and MP5Ks go.  My MKE also had a factory contoured grip.  Of all the HK grips out there, the contoured is the one I like best but there is one I like even more – the “Magpul SL Grip for HK94, HK93, 91 and Semi Shelf Clones”.  That one heck of a long product name – just remember the model – MAG1070-BLK.

This is the Magpul “SL Grip Module for HK94/93/91/MP5 & Semi Shelf HK Clones” – Model MAG1070-BLK
Zenith ZF5-P. Very nicely made pistol. Relatively bland grip.
Century Imports’ MKE AP5-P. It’s excellent. I like the contour grip more but that’s a personal preference.

A few months ago, I installed one on my Zenith ZF5-P and really liked it.  Whereas the MKE has a contoured grip, the Zenith has a basic straight grip that is only slightly more ergonomic than a rounded rectangle.  I’d read a few posts about guys converting over the Magpul grip, so I did the same.  You know what? I realy like it.

Here it is on the Zenith. By the way, that is Magpul’s cool ESK Extended Selector Lever. I have links to them at the bottom of the post.
Here’s the second one on my MKE AP5-P.

Doing the Conversion

The Magpul SL grip wasn’t designed for use on a MP5K but what you need to do is pretty straight forward if you have the tools and at least some basic knowledge of locating holes to be drilled.

Let’s go over some basics – first off, the steel “tail” that sticks out of the Magpul will need to be cut off.  I’d recommend using something like a hacksaw, reciprocating saw or a bandsaw.  I have a metal cutting bandsaw so I used that. Please notice I did not list a Dremel or similar rotary tool with an abrasive wheel.  They risk making the steel so hot that the plastic could be damaged.

The first step was to cut off the tail. I did it flush with the end of the plastic and cleaned it up with a belt sander.

Next, sand the tail end smooth.  Take off as little material as possible as it will help you get a solid lockup.

Take off as little material as you can until the grip fits and the end cap, brace or stock can fully seat. By the way, I should have cleaned up a bit more before this photo – the dust you see if from me sanding Hungarian Grey-Blue AMD grips that we make. The dust is not from the Magpul grip – it will be black flecks of plastic and a bit of metal from the steel reinforcing channel inside the rear.

As you may have noticed, many MP5K-type weapons, such as those from MKE and Zenith, use two small pins to retain the grip assembly – one in the front at the bottom and one in the top rear.  With the semi shelf and a snug fit, you just need the single rear pin to hold the grip’s rear end up and in place.

The front of the grip has a plate that interfaces with the semi shelf on your MP5K.  Magpul includes instructions for SP5 owners that they may need to remove a little material for a good fit and I would assume this extends to the SP5K but I don’t know this for sure.  With both my MKE and Zenith, no adustment was needed.

That little rectangle welded just to the right of the front grip pin hole is the semi shelf.
This is the locking plate for the grip that interfaces with the semi shelf at the bottom slot in the photo (if the weapon were held upside down, it would be the slot at the top .)

In terms of locating the hole, take your current grip and measure backwards from the front locking plate to the center of the hole.  Then, measure down from the top of the grip.  Use these two measures to locate where you need to do your cutting and then setup your mill accordingly or at least a good drill press because all you are doing is plunge cuts.

Measure the hole from the locking plate to where the center of the hole is on your existing grip – this is the horizontal measure. I’d recommend using calipers to do this. You then need to do the vertical location by measuring from the top of the grip to the center of the existing hole. The more precise you can be, the better your results will be.

Cutting the rear hole. 

Critical: You must make an insert from hard wood, plastic, or aluminum. If you don’t, the walls of the grip will flex and your holes are going to be a mess. I learned this the hard way. The width left to right is about 7/8″ and then you can decide how you want to handle the vertical. I’d recommend surrounding the area where you want to make the cut. I run my insert the whole length of the inside top to provide a firm support both for the clamps and the plunge cuts. You don’t wany anything to flex.
If you don’t have an insert to keep the grip open, they will flex as you attempt to cut them and you’ll make a mess. This is 7/8″ left to right. I then made it the length I wanted. The “leg” on the left bottom is to help it stay in position in the grip. The hole on the right shows you where the 6mm end mill plunges into it.

The first step is to cut the reliefs where the pin goes. The head of the takedown pin is about 9-9.1mm wide. A 9.5mm cut doesn’t give you much room to adjust.  10mm is just a tad wider and gives you more room to adjust your cuts later with a circular file and not have the head unable to sit down in the recess. The reliefs need to be cut about 3mm deep.

That is a 10mm end mill and I just finished a 3mm deep cut. A 9.5mm head would give you a tighter fit around the head of the pin but 10mm gives you some adjustment room.

Next is to cut the 6mm holes for the pins. I’d recommend against a drill bit as it might get squirrely on you – both in terms of deflection or the bit getting caught on one of the holes in the steel reinforcement.  Get a 6mm carbide end mill, make sure your grip is held securely and do a plunge cut.

A 6mm end mill was used to plunge cut the center hole for the pin.
Here is the MKE Pin with an OD head diameter of 9.1mm. The countersink was cut 10mm wide and 3mm deep. This gives a bit more room for adjustments.

If you do use a drill press, check your runout.  If you have more than 0.5mm on one side, you risk cutting to big of a hole.  You want to be somewhere between 6.0 and 6.1mm.  If you go too wide, the retaining wire may not get a good enough hold to keep the pin in place.

Cleaning Up

Use a fine file or diamond abrasive stick to remove all material left over from cutting inside the grip so you have a smooth surface.

It’s time to test fit the grip.  It may go in great all by itself or you may need to adjust it just a tad with a circular file.  I’d recommend a 6mm tapered circular file so you have a lot of control. 

This 6mm tapered Bahco file is great for adjusting holes. Click here to see it on Amazon.
Use a circular file to adjust the grip until it fits. Don’t rush – take off a bit and test, take off a bit and test until it fits. That is the Bahco 6mm file I mentioned earlier. It’s great for this kind of work.

Note, test fitting the grip by itself is one thing.  Doing it with the stock, brace or endcap in place is another.  You may find further adjustments with the circular file are required.  Also, you can make things fit sometimes by moving or tapping the grip or whatever is on the end around.  The sheet metal of the receiver can flex and sometimes it gives you just enough alignment to push the pin on through.  I often tap (not bang) them in with a small hammer with a non-marring head.

You want everything to be snug. You’ll find the front pin doesn’t matter if everything is tight.  If you really want a front pin, you would need to make a custom pin given the width of the Magul’s front lower “ears”.  It would also only be cosmetic because you would be inserting a steel pin into soft plastic that does not have a reinforcing plate. 

The moral of the story is to keep the front-to-back length of the grip long so it is snug – again, don’t cut or sand off more of the black plastic than you must.  Also, try to be as close as you can with the pin holes at least vertically.  Because of how the grip is sandwiched between the mag well and whatever is on the rear, it’s not going anywhere.  The rear pin is the final part to limit movement.

I used the file to slot the hole backward just a bit. Note how tight the grip is up against my SB Tactical brace. It’s not going to wiggle.

The Results

The MKE feels great. I will upgrade the selector the Magpul ESK but even with the stock MKE selector I like the feel more.

Summary

I hope this helps you out if you want to do this yourself.  For folks who just want to do the final filing adjustments, we will converted Magpul grips for sale. Please click here to go to our store.

Here are the original Magpul grips in case you are looking for them:

Production Grip Comment

For our production grips. the holes are based on a new unissued German MP5K grip. Depending on a bunch of factors, the exact holes in the grip you get will vary a bit. Fitting will be required – front to back and the hole locations.

If you find this post useful, please share the link on Facebook, with your friends, etc. Your support is much appreciated and if you have any feedback, please email me at in**@ro*********.com . Please note that for links to other websites, I may be paid via an affiliate program such as Avantlink, Impact, Amazon and eBay.

If you are looking for an extended selector lever for your MP5 or MP5K, these are really nice.

Roller Locks - HK

Best MP5/MP5K Upgrade Ever – The Timney MP5 2-Stage Trigger

I hate bad triggers and the worst triggers I have ever used were on HK MP5 and MP5K weapons. I have no idea of the design intent – maybe a real strong emphasis on avoiding an accidental discharge by having a long spongy pull and then a break somewhere around eight pounds. For someone who likes crisp triggers and a lighter pull, the HK triggers in general can be a rude awakening.

I recently picked up Zenith Firearms ZF5-P, which is a MP5K clone. Zenith Firearms is based in Afton, VA, and make their various rifles and pistols there. They used to import MKE clones from Turkey but severed ties and are actually making them here in the US.

I bought the ZF5-P for a few reasons – First, I got a good deal on it. That always helps. Second, I no longer had any form of an MP5 and kind of wanted to get back in. Third, and the subject of this story, I knew Timney made a well-regarded trigger pack for the MP5/MP5K. Fourth, I had an urge to tinker and needed a test platform.

Now Zenith makes a big deal that they machine their cartridge walls vs. bending sheet metal resulting in a better trigger. I was kind of curious to check that out as well.

For the rest of the article, I’ll just refer to the trigger as an MP5 trigger because the MP5 and MP5K share the same trigger pack. It’s the grip that differs.

The Zenith’s Original Trigger

Well, I was hoping for a good trigger out of the box because of Zenith machining the walls of their trigger pack but to be honest, it was just another MP5 trigger. I bought a new Century MKE AP5-P and its trigger was better than the Zenith’s also. It’s not that the Zenith’s trigger is bad – my point is that the unit I received was no better than any other MP5 trigger I’ve used.

I used a Wheeler “Professional Digital Trigger Pull Gauge” and did 10 pulls of the trigger after lubrication plus I had pulled the trigger maybe two dozen times since I bought it so there was a tad bit of wear in before testing. At any rate, the lightest pull was 7 pounds 5.9oz. The heaviest was 7 pounds 13.5 ounces and the average came in at 7 pounds 11.3 ounces. So, just shy of 7.75 or seven and three quarter pounds. Still long, creepy, spongy … pick the bad discriptor you like.

The Timney MP5 2-Stage Trigger

It’s nicely machined and ready to go. You just need to move the ejector, ejector axle and ejector spring from your old trigger to this one. It’s easy to do.

These triggers are compatible with SEF/ Semi-Auto trigger packs and their style of safety selector levers.

These triggers are NOT compatible with Ambi/Navy/FBI trigger packs or .22 clones, as they are different internally.

Timney provides clear installation instructions in the package plus they have the following video to help with the install.

Folks, that trigger is amazing. Here are pull test results: Minimum pull weight was 3 pounds 2.7 oz. Maximum was 4 pounds 0.1 ounce. The average was 3 pounds 10.3 oz.

I’d call it crisp and clean. Night and day better than the original Zenith trigger.

Range Time

My brother-in-law, nephew and I took the Zenith ZF5-P and a Century MKE AP5-P to the range. For an MP5, the MKE’s trigger is fairly decent but was seriously beaten by the Timney.

My nephew really liked the Timney trigger – we all did. By the way, one thing I really like is that a B&T low profile optics mount enables you to cowitness a Vortex Crossfire red dot with the iron sights.

Summary

I have never hid my dislike of MP5 triggers – I genuinely don’t like them and the only good things I can say are that they are reliable and you’ll probably never have an accidental discharge.

The Timney trigger ranks as one of the best upgrades I have done to a firearm. If you want a better trigger for your MP5/MP5K, or a clone of them, then get the Timney trigger.

Note, I have to buy all of my parts – nothing here was paid for by sponsors, etc. I do make a small amount if you click on an ad and buy something but that is it. You’re getting my real opinion on stuff.

If you find this post useful, please share the link on Facebook, with your friends, etc. Your support is much appreciated and if you have any feedback, please email me at in**@ro*********.com . Please note that for links to other websites, I may be paid via an affiliate program such as Avantlink, Impact, Amazon and eBay.

Firearms Building and Gunsmithing, Fixing Stuff, Tools

Vevor 30L Ultrasonic Cleaner is Great

I’ve heard about using ultrasonic cleaners on firearms for years but never really investigated them.  Recently, I had a need to clean a bunch of HK33 grips that had cosmoline, oil, and whatever else on them.  Actually, I knew well in advance because they were part of a project and I had to figure out how to clean up a 50+ of these used grimy grips.

The HK 33 grips had cosmoline on them.

My Cleaning Options

I knew cleaning that many by hand with a solvent would take forever and be expensive.  Hot water and dish soap was an option but slow and time consuming.  An ultrasonic cleaner seemed like a perfect solution.  I talked it over with my friend Scott, who owns Michigan Gun Exchange.  Scott has one in his shop and uses it to clean firearms.  He showed me how it worked and I was impressed.  This type of cleaning would be perfect.

Ultrasonic Cleaners

An ultrasonic cleaner cleans parts three ways – the liquid bath, ultrasonic vibrations and heat all combined at once.  If you’ve every fought getting cosmoline or old grease that has set up, you know how heat is your friend.

Okay, it was time to research.  I couldn’t afford or have the space for a giant unit.  Doing some digging, the Vevor 30 liter unit got good reviews and looked like it would work for the majority of firearm parts I would need to put in it.  I considered the length, width, height and the diagonal for really long parts.   The stainless basket you put the parts in measures 18.3″ x 10.8″ x 6.7″. The diagonal is 21.25″.

Note, in terms of actual volume it holds, they say the unit is 30 liters in the title but also report that it measures between 29 and 30 liters or 7.7-7.9 gallons. They recommend the fluid be at least 75% full to protect the heating element plus you never run an ultrasonic cleaner dry or it can damage the unit.

By the way, on a larger unit like this, make sure it has a drain valve and the Vevor 30L does.

Yes, it would work so I ordered it off Amazon.

This is the Vevor 30L cleaner. The unit is simple to operate with the temperature on the left and the timer on the right,

Deciding On The Solvent To Use

Dedicated ultrasonic cleaner fluids are rediculously expensive.  What a lot of gun guys do is to use 50:50 Simple Green and water.  I started reading more on that and there was one small detail I wanted to avoid –  aluminum left in plain Simple Green for too long is apt to react and cause pitting.  The aluminum friendly formulation is Simple Green Pro HD. 

I’d recommend using Simpe Green Pro HD because it is aluminum friendly. I know guys using the regular Simple Green at a 50:50 ratio and they aren’t having problems – my suspicion is that the parts in the liquid long enough for a problem to happen.

Simple Green’s recommended ratios for their Pro HD formulation are: 

  • For heavy cleaning: 1 part Pro HD to 3 parts water
  • For medium cleaning: 1 part Pro HD to 5 parts water
  • For light cleaning: 1 part Pro HD to 10 parts water

Well, given how thick cosmoline, grease and oil can be, I went with the heavy cleaning 1:3 ratio and it worked great.

Two comments – first, I bought mine from Home Depot. They ship to a home for free in my area. Amazon is rediculously expensive due to the weight. Second, I didn’t find out until later that Simple Green also has an “Extreme Aircraft and Precision Cleaner” formula. I might try that in the future as they expressly made it to not react with plastics, composites, aluminum, etc.

Heating the Tank

One complaint of folks using the large ultrasonic cleaners is that their internal heaters take hours to heat the fluid up.  Well, I can’t wait hours so did some digging on that front and bought an immersion heater.  They all have a potential shock hazard so you do not want to put your hand in the fluid while heating it. 

I bought an immersion heater made by HAIYEATBNB off Amazon. because it has a temperature regulator and got good reviews — it’s a game changer.  Scott bought one after I told him how fast it heated the tank. 

To be clear, the immersion heater is to dramatically speed up the heating of the solvent and then it is removed. A quick summary of steps is to put the heater in the fluid, plug in the unit and set the temperature, let it heat it up, unplug the heater, let it cool off a tad before you remove it and set it in a container so it doesn’t drip. The Vevor cleaner’s internal heating unit can maintain the temperature. The immersion heater is just fast forwarding the heating process.

The recommended temperature range for ultrasonic cleaners range from  130-180 degrees Farenheit. The theortetical “best” temperature for cavitation is 158F (70C) and guys report great luck between 155 and 165. Just bear in mind that the hotter you go, the more evaporation you will have also.

This is the HAIYEATBNB immersion heater. I like having the temperature control and the actual heating element contained inside the metal shield that has the stars on it. Yeah, I am sure the shape will cause some jokes but it works quite nicely.
The immersion heater sped things up dramatically. I could bring the tank up to temperature in 30-40 minutes. The exact time depends on the volume of liquid and what the starting temperature of the fluid is.
The immersion heater’s temperature gauge will not match the ultrasonic cleaner’s temperature gauge. If you want to know the actual temperature more accurately, you use a more precise instrument such as my Fluke 62 Max+ shown here. Note, the temperatures will vary depending on where you point it. At some point you just have to say “close enough” and call it even.

Safety comment: There is the potential for electric shock with any immersion heater. We used them on our farm growing up and survived. I’m not too sure I would worry about any freaked out electric shock comments you see in all of the reviews on Amazon across most of the heaters I looked at. Simply put, avoid sticking your hand in there while it is heating. Standing barefoot in a puddle of water that has an earth ground while putting your hand in the solvent during operation of the immersion heater will get you shocked so don’t do that!! Sheesh.

Testing

I timed the ordering with everything arriving so I could immediately put the unit into use. If it was going to fail, I wanted to know as soon as possible so I could return it.

In terms of fluid, Vevor recommends you have at least three quarters full or you may damage the unit.  If the fluid capacity is about 7.7 gallons then this puts it at 5.8 gallons of fluid. (The above photos do not reflect this just to be clear – I had about three to four gallons in when I snapped them.)

I then put in the immersion heater and watched the temperatures climb both on the heater and cleaner’s gauges and they didn’t match.  That really wasn’t surprising to me.  It’s hard to say which is more accurate but I decided to go with the temperature measurement from the Vevor cleaner. They claim their temperature reading is within +/- 5 degrees celsius which would be about +/- 9 degress Farenheit if I am doing my math right.

Given the size of the unit I could easily put two grip modules in side by side and that’s what I did.  I didn’t try stacking them as that might reduce the cleaning effectiveness.  I put the unit’s timer at five minutes and let it run.  It was fascinating to watch the crud come off – even the red and white paint filler in the S-U-O symbols on the grip were dissolving.

The cleaner was fascinating to watch operate. I took this photo because you caan see the paint dissolving from the selector position marks.

I read a few complaints about the noise these things generate.  The Vevor makes a buzzing sound for sure.  Maybe it’s just me but it really didn’t bother me.  I didn’t need it to be quiet – I needed it to clean stuff.

The timer went off, I then removed the units, sprayed them down with water to remove the cleaner and then used an air line to blow all of the water out. 

The results were amazing.  Scott had warned me that everything comes off – including the “sheen” of the black plastic resulting in a dull charcoal color.  I then went on to do about a dozen more.  In two or threee cases there was still some caked on cosmoline inside the grips that a second pass got rid of.

The results were very impressive. In just a few cases did I run a grip through a second time.

Have A Plan to Avoid Rusting Afterwards

I should tell you to have a game plan to avoid flash rust forming on steel items you clean.  Ultrasonic cleaners will strip all the oil and grease off so that means untreated steel can form rust when exposed to moisture in the air.  “Flash rusting” is a term for when bare steel is exposed to moisture in the air and starts to show visible rust within minutes of exposure.

Spraying WD-40 can help displace water – another option is to use compressed air if you have access to all surfaces – first but then you need something to prevent rust such as a light spray oil or whatever your preference is.  My point is to think it through to avoid flash rusting after you clean.

Summary

At this point, I am very happy with the Vevor 30L ultrasonic cleaner.  If you have ever wanted to get into ultrasonic cleaning for whatever you are working on, the Vevor units are cost effective and you just need to decide on what size works for you. Click here for a listing of Vevor cleaners on Amazon and here for all brands.

I hope this helps you out.

Note, I have to buy all of my parts – nothing here was paid for by sponsors, etc. I do make a small amount if you click on an ad and buy something but that is it. You’re getting my real opinion on stuff.

If you find this post useful, please share the link on Facebook, with your friends, etc. Your support is much appreciated and if you have any feedback, please email me at in**@ro*********.com . Please note that for links to other websites, I may be paid via an affiliate program such as Avantlink, Impact, Amazon and eBay.