Tag Archives: MP5K

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.

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.

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.

Germany plus Historical East and West, Roller Locks - HK

Brace Options for the HK SP5K

1 Comment

In the last post, I told you I bought an HK SP5K.  It’s relatively heavy and begging for a brace.  I don’t really feel the need to spend the money and wait to register it to be a Short Barreled Rifle (SBR) and there are actually a ton of arm brace options out there. 

Option 1:  The SBT5KA Brace

I have a SB Tactical SBT5A Brace on my POF-5 and really like it.    I knew they made a version for the SP5K known as the SBT5KA but I was hoping for something different. Please note they are two different models of braces reflecting the different receiver end caps.

Option 2:  The SOB Brace

Every time I write this product name – the “SOB” – down, I smile.  SB Tactical has a ton of braces for the AR/M4 weapons family and they have evolved a ton away from the ugly original.  The SOB has clean lines and I run one on my PTR PDWR.  I think it looks good and has handled the .308 rounds from the PDWR just fine and feels solid too.

Option 3:  The SBPDW

I thought I had found just what I wanted with the SBPDW – a collapsing stock that looked really slick and it would be easy enough to add an M4 adapter to the SP5K.  So, I ordered a very well made adapter and the expensive SBPDW stock and guess what?  It would not fit.

Needless to say, I was bummed.  I had it completely installed only to find out that the guide rods on the SBPDW run right into the sides of the SP5K.  Crud.  I didn’t feel like figuring out all the changes that would be needed.

Purely for reference, here’s the same PDW brace now installed on a 10.5″ AR Pistol but that is a story for another day. It is a rock solid brace.

The Winner?  The SBT5KA

Well, I was bumming from the strike out with the SBPDW so I went with my second pick – the SBT5KA.  I felt it was most true to the lines of the MP5K and ordered one. As with their other braces, SB Tactical did a great job.

Installation was a breeze.  Pull out the two small pins at the back, swap the old end-cap for the brace, push them together and reinsert the pins.  I did make sure the recoil rod lined up and nothing was binding as I reassembled the unit.

I Did Clean and Lube The Internals

I should point out that when I removed the end cap, I went ahead and slid out the bolt group and lubricated everything.  I applied Super Lube grease to the bolt body and Mobil 1 Synthetic 10w30 via a precision oiler to the rollers of the bolt and rotating surfaces.  I also oiled the pins on the trigger pack while greasing the hammer face with Super Lube.

Summary

So you see I went with the SBT5KA brace.  In the next post I will discuss handguards.

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.