Category Archives: Roller Locks – HK

AKBuilds, ARBuilds, Firearms Building and Gunsmithing, POF, PTR, Roller Locks - HK, Shotguns, Sten, Uzi Builds, Zenith

Tips on Finding Decent Gunsmithing Tools on eBay

One of the challenges when starting out working on guns is building your tool collection.  It’s hard to find cost effective tools so you wind up making do with stuff, creating tools ad hoc, etc.  Interestingly enough, this is where eBay just might help.  While I’m not happy with their anti-gun position, there are a lot of tools that pop up there – ranging from low-end Chinese stuff all the way to some beautiful vintage tools.

So, I want to show some example searches with 20 live feeds from each section:

Gunsmith and Gunsmithing Tools

The trick is in the searching.  For example, here are the top 20 matches for gunsmith tools or gunsmithing tools and you will probably see a mix:

[ebayfeedsforwordpress feed=”https://www.auctionrequest.com/arfeed.php?uid=inf5efd3d98495c&keyword=%28gunsmith+tools%2Cgunsmithing+tools%29&sortOrder=BestMatch&programid=1&campaignid=5338063879&toolid=10039&listingType1=All&feedType=rss&lgeo=1″ items=”20″]

Of course there are brands I will steer away from such as NCStar and others that I will look closer at such as Brownells, Lyman, Tipton, Weaver, etc.  I also read the ratings of the seller.  If a seller has a good rating and more than 30 sales, that’s a good sign.  Less than that and you are taking a gamble.

Vintage Gunsmith Tools

“Vintage” seems to be a popular term for “used”.  You tend to find a lot of unique stuff that was made by a gunsmith to fit a special need as well as high-quality tools that were made with care vs. mass produced.  Be careful though.  I’ll zoom into the photos as much as I can plus look at the seller’s description and the rating of the seller to try and decide if the tools are in good shape or beat to death.

[ebayfeedsforwordpress feed=”https://www.auctionrequest.com/arfeed.php?uid=inf5efd3d98495c&keyword=vintage+gunsmith+tools&sortOrder=BestMatch&programid=1&campaignid=5338063879&toolid=10039&listingType1=All&feedType=rss&lgeo=1″ items=”30″]

Used Gunsmith Tools

“Used” is still a popular term and is worth checking also.  Bear in mind the cautions I gave under vintage.

[ebayfeedsforwordpress feed=”https://www.auctionrequest.com/arfeed.php?uid=inf5efd3d98495c&keyword=used+gunsmith+tools&sortOrder=BestMatch&programid=1&campaignid=5338063879&toolid=10039&listingType1=All&feedType=rss&lgeo=1″ items=”30″]

Brownells Gunsmith Tools

Brownells has been around a long time — they were founded in 1939 and have always been known for their quality tools, parts and supplies to gunsmiths.  Because they have been around for so long, you tend to see a fair amount of Brownells stuff hit eBay by name so that is worth searching.  Still look at the photos closely and the seller’s rating to play it safe.  By the way, if you have never read their Gunsmith Kinks books – be sure to pick them up.

[ebayfeedsforwordpress feed=”https://www.auctionrequest.com/arfeed.php?uid=inf5efd3d98495c&keyword=%28Brownells+gunsmith%2Cbrownells+tools%29&sortOrder=BestMatch&programid=1&campaignid=5338063879&toolid=10039&listingType1=All&feedType=rss&lgeo=1″ items=”30″]

Antique Tools

What is “antique” really is up to the seller.  You’ll see stuff that ranges from a few years to over 50 years old.

[ebayfeedsforwordpress feed=”https://www.auctionrequest.com/arfeed.php?uid=inf5efd3d98495c&keyword=antique+gunsmith+-%28ratchet%2Cair%29&sortOrder=BestMatch&programid=1&campaignid=5338063879&toolid=10039&listingType1=All&feedType=rss&lgeo=1″ items=”20″]

I hope this helps you out!  There is a ton of stuff out there if you experiment with the search terms some.

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.

AK & Related Rifles, AKBuilds, AR & Related Rifles and Pistols, ARBuilds, Firearms Building and Gunsmithing, POF, PTR, Roller Locks - HK, Shooting in General, Shotguns, Zenith

Switched to Super Lube Multi-Purpose Synthetic Grease For All of My Firearms

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I’m always searching for better lubricants.  Many of the so-called specialty weapons lubes are just marketing hype with some bulk lubricant poured into their container.  In terms of greases, I’ve used quite a few over the years including wheel bearing grease and Tetra Gun Grease.  I wanted to find something effective, non-toxic and less expensive.

A name popped up when surfing – Super Lube.  To be honest, the first few times I totally dismissed the name because it sounds like some overly-hyped wonder lube that is sold in infomercials.  However, the name did keep popping up so I actually started reading up on it.

Super Lube products are made by Synco Chemical Corporation of Bohemia, NU, that was founded in 1980.  Their specialization is in the space of synthetic food grade lubricants and hold a number of patents.

There are a number of interesting characteristics about their grease that should be noted:

  1. It is designed to disperse very finely ground micron-sized PTFE (Polytetrafluoroethylene) which is a non-stick coating and lubricant.  You probably know it by the brand name of Teflon.  The approach they developed is one of their patents.
  2. It does not contain silicone
  3. It will work in a wide range of temperatures from -45 to +450 Farenheit
  4. It’s thickness is NLGI class 2, which means it’s about the same as vaseline or peanut butter.
  5. It’s non-toxic and food safe – here is the MSDS/SDS
  6. It will not melt or separate
  7. It will not dry out or get gummy
  8. It is waterproof
  9. It does not stain and is odorless – for you folks who do concealed carry or shoot a lot in uniform, you might want to take note of that.

Their website has a ton of information on Super Lube and also on lubrication in general if you want to spend some time reading.

I bought a 14.1oz tub of the Super Lube Multi-Purpose grease off Amazon – very affordable to say the least – clicking on this will open a list on Amazon.

To apply it, I use either a chip brush that I store in a zip loc bag to keep from getting dirty (as shown in the featured photo above) or a small flux / resin brush that I also keep in a baggy.

So, for the last few months I have been testing it.  When I cleaned one of my rifles or pistols, I would replace whatever I had been using as grease with the Super Lube Multi-Purpose grease.

I go by the old saying that if it rotates, oil it.  If it slides, grease it.  That is my rule of thumb so it goes on AK rails, bolt carriers, where the trigger hook grabs the hammer, etc.

It works great!  The weapons feel well lubricated after cleaning and they function great.  When I take them apart again for cleaning, the Super Lube shows no sign of breaking down, drying out, becoming gummy, etc.

If you are looking for an excellent affordable grease, check out Super Lube.  I’m definitely very happy with it.

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.

Pakistan, POF, Roller Locks - HK

Customizing and Shooting the Pakistani Ordnance Factory POF-5 Pistol

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Having watched one too many TV shows and movies with H&K’s MP5 submachine gun over the years, the sub gun has been on my “I want to have one list” for years but way out of my price range.  While surfing, I read about how Pakistani Ordnance Factory (POF) licensed the design and tooling necessary from H&K Germany to make roller locked weapons including MP5 clones.  In reading about the various Mp5 clones,  it became apparent that the POF-5 units are actually well regarded.  What really tipped the scales was a great post by T. Mark Graham at Arizona Response Systems who really knows his way around MP5s saying they were good to go with details of his analysis provided.

This led me to calling up Chuck at Kelly Enterprises and talking about whether to buy a Zenith (my first choice) or a POF.  Chuck is a very straight forward guy and tells it the way it is.  The Zenith would be hard to get and he had POF-5 pistols in stock plus he gave me a great deal so I ordered one and had it sent to my friend and FFL, Scott Igert, at Modern Antique Firearms.  Chuck sent me all the tracking info and just a few days later, the POF-5 was with Scott waiting for me to pick it up.

On inspection you could tell the receiver paint was a bit glossier than the more satin finish of an HK but other than the action feeling dry and new (that gritty not worn in feeling), it looked good to go.

Now, I have two personality quirks.  First, I can’t hit the broad side of a barn with a pistol let alone one this big and heavy.  Second, I can’t help but customize any gun I buy and this wasn’t any different.

I did a ton of reading and decided to go with a cool S&B brace, a B&T scope mount, Dakota Tactical handguard, a B&T muzzle brake and ordered a bunch of POF MP5 magazines.  You can buy the brace at PSA and Brownells. By the way, Brownells has a ton of replacement parts and aftermarket parts for the MP5 reflecting it’s long-time use by law enforcement no doubt – click here to see them.

Installing the brace was easy – like any HK, you push out the rear pin, pull off the cap and put on the brace.  I bought one all ready to go.

The handguard is a keymod unit from Dakota Tactical and they use a screw instead of a front pin to hold the unit in place.  It really locks up nice and I like the feel of it.  The rail section holding the Streamlight in the below photo is made by Monoki.

Now the scope mount is the standard B&T universal rail, the BT-21262-1.  I would caution against you buying a cheap optics mount for an HK-type weapon.  There are tons of stories of cheap ones falling off, not seating properly, etc.  The B&T unit is a mil-grade unit.  You slide it on and then work the little claws or feet into position and then secure them with the supplied screws.

Next up  was to install the Vortex Crossfire Red Dot optic.  These are the latest red dots from Vortex and come with both low and high mounting options.

Out of the box it has the high mount installed for the AR enthusiasts but includes the low plate as well.

As you can see, with the default high riser on it, the optic is way too high.  I prefer optics as low as possible where I can get a good cheek weld.

It’s real easy to change – there are just four screws that need to be removed on the bottom.  I used a bit from my Weaver driver set vs. the supplied key which would work but is slow compared to a driver.

I have the Weaver Deluxe Tool Kit and use the drivers all the time.  I use the block and hammer some but not a great deal.

Notice that Loc-Tite Blue (the medium strength formula) is used to secure the screws.

Here’s the end result.  Note, I will install a quick release mount at a later date.

One side comment – you may find it funny that the thing that puzzled me most was the B&T brake.  It installs on the tri-lobe fitting on the muzzle. There is a quick release lever that baffled me until I carefully inspected it and saw that one end is open and a cross pin is retaining it.  I then pushed the other way and lever lifted right up.  Duh!  I’d never seen one before!  It is solid and I like it.

The case you see is a 32″ Blackhawk Homeland Security Weapons Carry Case.  It comes with one internal mag carrier and I added a second pouch.  They are sized for 30 round AR mags and you can get two 30-round MP5 magazines in each pouch pocket.

Next up, I cleaned the bore and lubricated the weapon – especially the bolt head and trigger pack.  Past experience taught me to go through and make sure it was ready.

Two of my brother-in-laws and I took it to the range.  We used 124 grain S&B FMJ ammo and it functioned great and was accurate.  We had a blast at 15-25 yards shooting it despite it being a brisk day.  I really like how this combination worked out.  We didn’t use the light but the green laser was nice and bright when we tried it out.

We put probably about 200 rounds through it.  You can now feel the action has really smoothed out and I wouldn’t hesitate using this for home defense if I needed – which is why I put the light on it.

All in all, I’m very pleased and would recommend the POF-5 to anyone looking for a semi-auto MP5-type pistol.

Update 10/6/2018:  We put almost 500 rounds through this pistol this summer without one single failure to feed or eject.  We mainly shot the 124 grain FMJ S&B ammo except for one time, as a test, I shot about 20 rounds of Hornady 135gr Critical Duty ammo with no problem.  All of the magazines used (and I have 10 of them) are POF magazines.  Honestly, this thing is awesome.  I’ve only cleaned and re-lubed it once so far but it is on the to-do list.

12/12/18 Update:  I recently bought an HK SP5K and am documenting my journey with it.  Click here for the first post.

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.

PTR, Roller Locks - HK, Shooting in General

Shooting the PTR PDWR – So Cool!

Folks, the PTR PDWR is a fun gun!  Yeah, I said the “gun” word because it just fits.  After taking the time to lubricate and clean the pistol as I wrote in the last post, my two brother-in-laws and I took it out to the range.

Plain and simple, it ran like a top.  We did not have one single problem of any kind.  We were running surplus aluminum mags from Robert RTG.  The ammo was Prvi Partizan (PPU)  .308 M80 145gr FMJ.  I’ve had great luck with PPU ammo over the years and have run a variety of their calibers and loads.  This .308 ammo comes in a heavy plastic sealed “battle pack” that SGAmmo sells.  If you don’t know SG Ammo, they are a great ammo supplier that is a family run business.  I buy most of my ammo from them and have nothing but good things to say about them.

We sighted the Vortex 1-6×24 Strike Eagle scope in at at about 25 yards and then just had fun.  We weren’t shooting for accuracy but were having fun shooting “zombies” as we called them with the big Splatterburst 18×24 silhouette targets that I really like.

This time out, I was using my new Howard Leight electronic ear muffs.  These are cool because they have directional sound amplification for normal sounds – like talking with your friends.  When you shoot, they immediately cut the sound off and protect your ears.  This is a real nice feature for me as I can’t hear a thing when I wear ear muffs due to my hearing loss and have to take them off to talk to someone.  At any rate, these Howard Leights have a great reputation and I must say that I am very happy with them.

One of my brother-in-laws was wearing my new MPOW headphones and thought they did a really good job on cutting down the sound.  These are a bargain price at Amazon and work way better than my old cheap Silencios in terms of hearing protection.

Now we did have a funny lesson learned – see how short the barrel is relative to the Caldwell front bag?  Yeah, if you get the muzzle brake over that bag and fire, it will rain some kind of brown pebbles (corncob media maybe?) down on you as the muzzle blast shreds the top of the bag 🙂  I have to confess, I am the one who did it and had to use duct tape to seal the top up so we could use it the rest of the day.

The whole point of the range visit was for me any my two brother-in-laws to have fun and function test the PDWR.  It performed admirably – neither of them are shooters and, for Jamie, this was his first time shooting anything – I think he did great.

Not one single problem – no feed issues, no ejection issues – it just performed great through about 200 rounds.

At any rate, I did learn a few things:

  1. It upheld the good opinion I have of PTR firearms.
  2. The SOB brace can handle .308 recoil just fine and lines the eye up for the scope great.
  3. As expected, the Vortex scope was great.
  4. The weight of the PDWR absorbs quite a bit of recoil making it a pleasant shooter but there is still recoil that moves you off target with any kind of rapid fire.
  5. The muzzle brake does an okay job but I am going to check into alternatives to cut the recoil down further.  The bird cage design is okay but there are definitely better designs out there.  The PDWR has a 5/8″-24 TPI threading so there are definitely options.
  6. The PDWR handguard moves forward and backward more than I care for.  I am going to experiment on tightening it up or either moving to a DTAC handguard or back to the original PTR handguard.  Note – the PDWR uses a MP5-style handguard.

Bottom line, I am very happy with the PDWR and plan to work with it some more on the above plus see how it does as I work my way back to 100 yards.  Everything in this sessions was at 25 yards or less and I am curious how it performs as the distance grows.  I would recommend the PDWR to anyone looking for a short HK91/G3-type roller lock for short distance use.

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.

PTR, Roller Locks - HK, Shooting in General

Lubricating the PTR PDWR and Cleaning the Barrel

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The last step in preparation for my first trip to the range was to clean and lubricate the PTR PDWR.   One thing I learned with my for PTR was that proper lubrication makes a world of difference and I could tell in working the PDWR that it definitely need lubricating so here’s what I did.

If you have any questions about field stripping, watch this video:

Also, if you need any parts diagrams or more detailed questions, be sure to read the HK G3 Armorer’s Manual.

In general, you know you need to lubricate all moving parts of the firearm such as the trigger and bolt.  So let’s start with the trigger.

Lubricating the Trigger Pack:

I employ a very old rule of thumb – If it slides, grease it.  If it rotates, oil it.  That simple rule has helped me take care of a ton of rifles and pistols over the years and can help you too.  [Click here for more on lubricating a firearm in general]

I used a small squeeze bottle filled with Mobil 1 Full Synthetic 5W-30 to reach in and lubricate all places where a part rotated on a pin.  I then worked the various parts of the trigger pack to make sure the oil go to where it needed to go.I used Tetra Gun Grease to liberally coat the top of the hammer.

Lubricating the Bolt Assembly:

Now the HK bolt assembly is involved and the following is a diagram from the HK G3 Armorer’s Manual:

 

In short, I oiled all of the internals but did not fully disassemble the bolt.  I put the assembly into a non-marring vise, twisted the bolt head off and then reached in with the squeeze bottle to lubricate the rollers, locking piece, firing pin, etc.

After that I applied a thin coat of Tetra Grease to the bolt carrier body and put more on the bottom and sides of the bolt where it would be making contact with the receiver and riding over the hammer.

Cleaned the Barrel:

One thing I always do before heading to the range is to clean the barrel.  If you look down in most, you will see varying levels of crud ranging from oil to dust to stuff left over from machining.  In the case of the PDWR, the barrel looked pretty good but I still wanted to clean it.

Over the years I have tried all kinds of different approaches to cleaning barrels.  The fast and easy one I use now on non-precision firearms that just need a touch up is a bore snake.   These things are caliber specific and give you everything you need in an “all in one approach”.  I spray CLP on the snake and down the barrel then I drop the weighted cord down the barrel and pull the snake on through.  I repeat this until the bore is shiny bright.

Note, there are a ton of brands including cheap generic imports.  I’ve used Hoppes and Sage & Braker brands with no problems at all.

At this point the PDWR was ready for the range.  The action felt and sounded good.

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, PTR, Roller Locks - HK

Fixing a Bent Sight and Cocking Lever Tube Bur On The PTR PDWR

Okay, when I received the PTR PDWR I did a quick inspection and noticed two small problems that needed fixing.  I’m a bit disappointed that PTR quality control did not catch these two items but they are small issues.

First, the front sight blade was bent sideways – to canted, bent.  I’m not sure how this happened but thankfully the HK-style hooded sight uses a sheet metal insert for the front post.  The following illustration is from the HK G3 Armorer’s Manual:

I figured the easiest thing to try was to simply reach in with pliers with padded jaws and see if I could simply bend it to the right to straighten it.  Out came my purple art pliers 🙂  I literally bought these things back in 2013 for some kind of work that required padded jaws.  I don’t recall what and as odd as they look, they have held up to light use.  My only complaint is that the nylon jaw covers can slide off under very much stress but that was not an issue here at all.

They actually fit perfectly and I was able to bend the sight post straight.  Plan B would be to take a pair of needle nose pliers and slide rubber fuel line hose over the jaws.  My one concern would be whether the relatively thin jaws could adequately support the post during bending.  The art pliers below fit and did the job perfectly.

Fixing a Bur on the Cocking Lever Tube

The second problem I needed to fix was a steel bur on the tip of the cocking handle catch.  It bugged me every time my hand hit it and should not have been there.  Here it is in the next photo – sharp and pointing out.

From years of experience, I knew the pistol needed to be field stripped first otherwise the resulting debris would be messing with the action.    The following is a good video on what to do:

In terms of the repair itself, first, I reached in with a Dremel using a small medium grit sanding drum and the tool on slow speed to knock down the sharp irregular edge from the inside.  Take your time – remove a little and look.  Your goal is always to remove as little material as possible.  As the old saying goes, it is easier to take more off than try and put it back on 🙂

In the next photo, you can see the “point” has been sanded down but there is still material on the surface:

Next, I used a 120 grit small flap sander in my bench mounted rotary tool to sand down that lip.  I could have used my Dremel but I use the little flap sander attachment so much that I routinely leave it in my bench tool.

Again, the trick is to go slow and take your time.  After that, I used compressed air to blow out the tube and receiver and then used carb cleaner spray to “wash out” anything that might have stuck and blew it out one last time.  The bur was gone and now it was on to lubricating the weapon.

(Note, that last photo above has the bolt back in when I was testing it later).

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.

PTR, Roller Locks - HK

Adding a Vortex 1-6×24 Strike Eagle Scope to the PTR PDWR

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I really prefer an optic on my firearms at this point.  The PTR PDWR is a relative short range pistol so I figure post of my shots will be within 100 yards.  It could certainly shoot further but, based on what I have read so far, the accuracy goes down hill fast.

While some might consider a red dot, I opted for a true 1-6×24 Vortex Strike Eagle scope that has a 30mm tube.  Now, I have to admit that I have become a bit of a scope snob over the years.  I’ve destroyed cheap scopes, suffered with dark images, short eye relief and what not.  About four to five years ago I happened upon Vortex and they have been my go to brand ever since – not only is the quality there but they back it up with a no-nonsense warranty.

Folks, I’ve owned probably at least a dozen Vortex scopes and red dots.  I still have six that are on firearms that I plan to keep.  I have had zero problems – not one.  Not out of the box and not over time.   I probably will some day – stuff happens.  I’ve talked to other guys who broke their scopes (literally) or had problems and sent them in with Vortex taking care of them no questions asked.  That says a lot.

So, that brings us to the scope.  The Strike Eagle is a decent entry-level AR scope with an illuminated reticle.  I bought this scope about a year ago for a project that didn’t happen and it has been sitting on the shelf.  The good news is that Vortex now also has a 1-8×24 model.

Mounting the Scope

I used to use cheap import cantilever scope mounts but have since stopped due to screws stripping out and easily scratched finishes.  I now use Vortex mounts pretty much exclusively now as well.  I know I sound like a salesman but I really like their stuff.

You’ll notice the quality of the finish and that the parts are beefy.  You can go 18 inch/pounds on the rings and 65 inch/pounds on the rail attachment nuts.  You’ll notice that cheap scope mounts don’t publish torque specs usually because they can’t handle much consistently.

The ring caps are secured by screws that have heads for #8 Torx bits.  They go into steel threaded inserts for added strength – you will not find steel inserts in cheap mounts by the way.  At any rate, lets begin.

Safety First:  Make sure your weapon is unloaded!

As you can see in the above photo, I located the mount on the PDWR’s Picatinny optics rail a few grooves forward of the rear sight.  It was a bit of an arbitrary point.  I know I usually am near the rear plus on my past HK-style weapons I knew I might have to work around the rear sight.

I removed the ring caps using a #8 Torx bit from my Weaver screw driver set and put them in a magnetic parts tray.  I have lost little parts in the past so I am a bit paranoid now.  I use my DeWalt cordless screwdriver to do the removal work as the twisting motion of a screw driver really messes with my carpal tunnel.

Next, I place the scope on the rings and the very first thing I check is the clearance over the rear sight.  In this case you can see the scope clears it.  Years ago with my first rifle, a GSG-522, I scratched a scope by not checking that before I started screwing down the rings.

Next, I install the ring caps back on.  A time saver I do is to use the Dremel to run the screws in but there’s a trick.  Hold the screw driver lightly so it can run the screws in but the screw driver turns in your hand the second it bottoms out.  You don’t want to apply torque – just run the screws in.  I then back them off just a bit so I adjust the scope in the mount.  I also adjust them in or out slightly so I can get any gap between the ring cap and the base equal all the way around.

I then shoulder the rifle and move the scope forward and backward until I get the proper eye relief.  You want to be able to pull the weapon up quickly and see through the whole scope vs. having to move your head around to get a good sight picture.

Also, I true the scope left to right.  If I were doing a precision rifle, I would do it differently but with the PDWR, I eyeballed the reticle relative to the position of the rifle to level the scope and then tightened down the ring caps.  I like to carefully take them down snug all the way around and then set the torque at 18 inch pounds with a Wheeler Fat Wrench – note that Fat Wrench does not have a clear 18 in/lbs setting so I try to get it close.

Once you are set, you also need to torque down the mount’s rail attachment screws to 65 inch pounds.

I was taught to never store a torque wrench under load so once I was done, I then adjusted the Fat Wrench back to zero.

At that point you are done.  While setting up the optic and installing the brace, I noticed some tuning was needed and that will be the next blog post.

Click here for the post about installing the SOB arm brace

Click here for the post about selecting and purchasing the PDWR

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.

PTR, Roller Locks - HK

Adding a Brace and Changing the Forearm on the PTR PDWR

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In the last blog post, I talked about the specifications and ordering the PTR PDWR.   Even before it arrived, I knew I wanted to add a brace.  My plan was to use PTR railed handguard and I had a “wait and see” attitude towards the brake.

So, the first step was to remove the existing end cap.   In HK-type weapons is is held in place by two push pins that are simply pushed back out.  You’ll notice that one side is relatively flat:

The other side will be protruding and this is the side that you push on and will remove the pins from the other side:

You then wiggle the end cap and push it off the end of the stamped receiver.  It will look like this:

I then secure the end cap assembly in a vise to make working on it easier.

In the next photo you can see how the tube and sling really are like a small stub of an AR/M4 buffer tube complete with an indexed end plate to keep it from rotating and a castle nut.  The swivel is separate from the tube and is threaded into place so unscrew and remove it first.

In the next photo, you can see the lighter grey castle nut on the black tube.  The light grey surface you can see in the otherwise black cap is the plate you will need to fish out after you back off the castle nut.

To remove the tube itself, you do the exact something you would on an AR.  Use a castle nut wrench to loosen the castle nut and then thread it back out of the way.  Then pull the end plate out of the receiver so it can rotate and then turn the tube to remove the assembly.

In the next photo you see the castle nut wrench on the tube with the sling.  I realized shortly after this was taken that I probably needed to get the sling off before I could back out the tube – that is why I said remove the sling first.

As written above, you will need to pull the end plate out of receiver to be able to turn the tube.  With the plate pulled out from the receiver, the tube simple unscrews.  If it does not want to unscrew, make sure your plate is out of the way.  Also in the next photo, you can see the very secure mount that the sling screw threaded into.  That was well thought out.

Next, I wanted a folding mechanism to be inline between the receiver cap and the buffer tube.  SBTactical makes a very sturdy 6061 aluminum unit known as the “BTFA”.  To install it meant the tower that the sling swivel screwed into needed to be removed.  It adds about 1.1″ to the length when installed.

The tower is held in place by two screws inside the cap.  Mine were beat half to death – the assembler at PTR must have figured nobody would ever notice.  He/she was wrong and I was disappointed that they had installed the screws with an undersized blade screw driver and tore up the slots.

Once I removed the tower, I just inserted three #10 washers between each of the screws so the aluminum end cap and the sheet metal assembly would all come back together nice and snug.  If I wanted to take the time, which I didn’t have, I should have found some of the correct size button head socket screws and replaced the beat up countersunk originals.  So, what I had looked like this and the screws were a bear to get in (Yes, I did use the correct size screw driver to put them back in.)

Putting it Together

The BTFA install is very simply.  Use the supplied allen wrench to loosen the disc assembly that is the threaded plug that goes into the receiver.  Do not remove them all the way – you just want to loosen it up so you can screw in all the thread and adjust the folder to the direction you want.  I wanted the stock to swing to the left to lock out of the way of the ejection port.  You then tighten down the allen screws back down.

I installed an SB PDW tube and an SB SOB (love that acronym) brace.  Now, to install the tube, I reused the PDWR’s end plate to and a new castle nut that came with the tube.

To install the buffer brace on the tube, I spray silicone on the tube so it can slide on way easier plus it makes it easier to true up the brace if it needs to move a little bit one way or the other.

One comment about the end result, it is a solid folder but the combination of tube and folder is long.  I will investigate other options and post the results in the future.

The Handguard

Now, in terms of the handguard, I thought I was going to use the original PTR model you see in the photos above.  It’s a little small left-to right in my hands so I actually wound up changing to a US made wide tropical forearm.  It’s a tad looser than I would care for and will post updates about that later.  I may stick with the existing wide tropical unit or move to a DTAC like I have on my POF-5.

12/17/18 Update:  I’ve now tried three or four models of MP5 handguard and they all wiggle.  I’m either going back to the PTR unit or a DTAC.  The DTAC handguard on my POF-5 has been solid as a rock.

Next up is the optic.

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