Ptr 91/k3p pdw

[precision_shooter]

Thinking of picking up a 12" barreled PTR 91/K3P PDW pistol and converting to an SBR (with proper stamp and paperwork of course)...

Anyone have one of these, either as a pistol, SBR, or carbine/rifle configuration?
How do you like it?
How sensitive is it on ammo it likes?
How does it shoot with steel cased ammo?

Been reading that with the fluted chambers, reloading the brass may not be a possibility. What say ye?

Thanks,
PS

 

[dakota.potts]

I've been doing a lot of research on this same thing and thought about SBR'ing a CETME. There are some issues there (it would require a newly designed locking piece or lightened bolt) however, I did pick up some general knowledge that may be helpful.

They tend to do well with 147-150 grain military FMJ ammo. Steel cased ammo is actually recommended, or 7.62 NATO brass, as the ejection is very rough and can separate commercial .308 Win cases. Reloading is said to be possible with the use of a buffer to keep ejection from denting the brass.

The system is a form of delayed blowback and a shorter barrel means less blowback. The PTR PDWs have a higher degree locking piece which allows the rollers to open with less blowback, so I don't have any information on how rough the ejection is on the PDW versus the full sized.

Been curious to shoot one of these myself, so be sure to write back with maybe some pictures

 

[Gunfixr]

I dont have one, but a friend has one of the hk91s with the 9" barrel as an sbr, an older original one. He doesnt shoot a lot, and doesnt reload, just shoots whatever he can get cheapest, and it has run all ive seen put through it.
I dont know if hes tried steel case, i havent seen it.
It has the collapsing stock on it.
A 12" may be better, but shooting that 9", its only fun for a couple mags. The blast is horrendous.
Just thought you might want a heads up.
Eta: his tears up brass just like the full size rifles do.

 

[Fishbed77]

Just be sure to post photos of the nighttime fireballs I would assume such a configuration would make.

 

[precision_shooter]

It should be a good flame thrower that's for sure, especially if I run a linear comp on it instead of a normal flash hider, but the linear comp should help direct the blast forward and away from the shooter.

From the videos I've seen, during the day the 12" barrel is not nearly as bad as the 8" version. Guess I will find out how it looks at dusk...

I will keep everyone updated on it.

 

[ttarp]

Don't worry about the flutes, they only leave superficial discoloration on the brass, the flutes do not harm the brass in such a way to hinder reloading. There are a lot of myths floating around about flutes being perpetuated by people who don't a clue what they're talking about.

During ejection the sides of the cases hit the receiver pretty hard causing the "HK smile", this dent if violent enough could be a problem for reloading.

Also sometimes the case mouths are crushed, I find this to be the case(is that a pun?) when I clean my PTRGI(don't have a K3P but I've had my eye on them) regularly, at one point I had about 1,000 rounds give or take without cleaning and it barely dented the brass at all.

Steel cased ammo shoots fine in mine, and like stated above its often recommended, and even though case head separations aren't too common in commercial .308, its good to be aware of the somewhat remote possibility.

Every one of these rifles is different, but as a rule of thumb, don't count on reloading roller lock brass.

 

[leadcounsel]

A 12" .308?!

Yikes.

 

[JJ45]

A PTR 32K in 7.62X39 would be more controllable and have somewhat less blast and recoil. The PTRs eat up Russian steel case ammo which is a lot cheaper than .308

 

[JJ45]

Oops, forgot to add the PTR 32K PDW is the 12.5" version of the 16 inch carbine chambered in X39...There is also an 8.5" barreled model.

 

[precision_shooter]

I looked at the PTR 32 as well, but like the 91/K3P better.

 

[stubbicatt]

OP, I do not have the short version, but I have found that if I use GI brass, and install a port buffer from RTG Parts, I can reload my brass, and it has no HK smile.

One of the reasons I am reluctant to purchase one of the versions with the welded on rail, as it looks to me as though the rail might make installation of the buffer problematic.

 

[precision_shooter]

Yeah, I thought about the welded rail after looking at the port buffers, but from further reading, it looks like others have had success modifying the buffer to fit with a welded rail... Won't know until I try I guess...

 

[precision_shooter]

Well, just ordered the K3P...

Will submit Form 1 once I have the gun in hand...

Question about the stock:

Do I just need the stock with buttpad and the buffer screw or do I need to replace the backplate as well?

 

[stubbicatt]

About the stock...

I called and spoke with PTR about this very question some time ago. They told me all one had to do was remove that sling attachment gizmo and install a standard stock in its place. I didn't ask whether one would need a buffer or not, so I guess that's something you can figure out when you get it. I suspect a standard buffer has been installed, which would account for the length of the pistol's sling attachment gizmo.

I have had good luck with the heavy buffer from HK, and also the one from Robert RTG parts, which is a modified standard buffer with a longer "probe". It does work better to reduce the recoil impulse than the standard ⅜ inch long buffer probe.

One of the questions I have is whether one would do better to replace the locking piece/wedge with another suited for the short barrel. The angles are ground in a little differently. This may only be an issue if one seeks to entertain himself with automatic fire, not sure.

 

[dakota.potts]

I think the 12.7" and 8.9" models come from the factory with the correct locking piece from that barrel length. Otherwise it seems like they would be bolt action firearms

 

[precision_shooter]

Thanks for the replies!

I don't see how the sling attachment could serve as the large buffer screw when adding a stock, but I could be wrong. Once I get it, I will know for sure.

From looking at pics, looks like I have to remove the dust cap/end cap that is attached to the backplate, then place stock on the back plate and secure the stock with the large buffer screw from inside the stock. I don't think this screw is present in pistol form, at least not one that would be used to secure the stock.

Since I will be in there, I may look to replace the buffer as well to the HK large buffer or the one from RTG. Thanks for the info on this.

 

[precision_shooter]

Ok, did some more reading...

Looks like people have nothing but good things to say about the Heavy Recoil Buffer made by PCS, and it's a little cheaper than others I found. Bad news is I could only find it for sell through RTG and they are sold out. Signed up for email notification when they become available.

I did go ahead and order a fixed stock, large buffer screw, a couple magazines, and HK91 manual from RTG.

Now it's just a waiting game to get the gun and parts, then file my Form 1 so I can put it all together.

Will write up a review with pics, and hopefully a video or two, once it's all squared away.

Thanks for all the input and suggestions!

 

[stubbicatt]

Precision Shooter, when I installed the RTG buffer on a PTR made plastic stock, the big buffer screw would not work, because the body of the buffer is nearly 2x as long as a standard buffer. The longer buffer slides right on through the buffer tube, and is not retained from the rear. The entire works was/is held in place by the two, short, screws that thread in through the end cap into the front of the stock. It hasn't been an issue thus far, but then again I haven't buttstroked anybody with it yet.

IIRC, the PTR stock has an "open" buffer tube cast into it, not a blind tube like the G3 surplus stocks. I don't think that it is intended to use the big screw that threads in through the hollow stock into the back of the buffer.

I guess it's a good thing / bad thing sort of situation. If you want to use a standard buffer, probably a surplus stock is a good idea as it is designed to use that big screw. If you want to use a longer buffer, then you would want to use a PTR manufactured stock section, and forego the big buffer screw.

Another option you might find helpful is the buffer sold by Bill Springfield. Pretty sure it uses a standard length buffer body. I do not know how effective it is, as I have not used one. Bill Springfield is a great guy and he can tell you more about it if you are curious.

Of course I'm only sharing what I have experienced from a full sized rifle, and I am relying upon your representation that you will obtain the proper tax stamp before attempting any such conversion on any pistol you will obtain. I have no intention of assisting in the illegal conversion of a PTR pistol.

Another option which would be pretty cool is the HK collapsible stock, affectionately referred to as a meat grinder. When collapsed it would make your firearm a really short, compact, and handy toy. When extended though, the twin struts of the stock make it a bit of a challenge to get behind the sights. I'm not sure whether PTR uses a collapsible mainspring guide rod like some manufacturers of G3 pattern pistols. If it does, then it might be a real challenge to use a collapsible stock, as one would have to find a way to install that guide rod into the end cap of the meat grinder. I don't know how to do that.

 

[precision_shooter]

I absolutely have no intention of building an illegal SBR. Tax stamp will be in hand before assembly.

The large buffer screw was $2, so if it ends up that it's not needed, then no big deal. The pistol comes with a standard buffer, so I think I will need the screw until I change the buffer.
I went back and forth on what stock to get, and the standard fixed stock was the cheapest option. Once I get the gun and stamp, I can always change the stock to something else later on, as long as it doesn't change the OAL of the weapon as filed on the form 1...

Thanks Stubbicat!

 

[ttarp]

Not following you on the buffer stubb, my PCS buffer uses all 3 screws. Are you saying the PTR stocks don't have the hardware to use the 3rd screw? If so I'd say pick up an HK stock like my PTR came with, you might as well set the rifle up like it was designed.