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HELP! PTR-91 Not working!

7K views 20 replies 13 participants last post by  Conelrad 
#1 ·
Hello all, and happy Thanksgiving!!

Well I went to do some pre-Turkey Day shooting yesterday with my Peepaw down by the creek.

My PTR-91 did NOT perform properly!! Keep in mind, I've fired almost 700 rounds up to this point, all good for the most part, but I just recently changed rollers for my bolt. It turns out my bolt gap had gone to about .005" from when it was new, but the gun was cycling properly. That seemed kind of on the low end. So I did some reading, and it appears the "ideal" bolt gap for these is something like .015", so I bought some +2 rollers from HK parts and installed them in the rifle. The bolt did indeed measure about .015" when I checked it after the install.

Now I went to shoot it for the first time yesteday, I was using Tulammo 150 grain steel cased stuff. This has worked reliably in the past for me. So, I chamber a round and BOOM! :D went off just fine. Then, I pull the trigger and "click"... no go. So I work the action again, making sure to lock the bolt back and slap the charging handle. The gun chambers fine and again, fires, but then a failure to fire on the next round. So, the gun is chambering the round and firing it, but it appears the bolt maybe is not closing all the way on the next shot.

I can see a slight 1/8" or so gap in front of the bolt after firing. However, I can still pull the trigger and this sometime leaves a small mark on the primer, but it doesn't set the round off. It seems that the gun is just not chambering all the way, and only chambers properly during manual manipulation of the bolt.

The gun was very clean, I make sure to scrub out the chamber after each range session so I don't think it's that. Do you think the larger rollers are causing this? If so, why? Should I go back to the small rollers? This is very strange, and if anyone knows how to fix this, please let me know. Thank you all so much, and have a great Thanksgiving!!

V/r

Earl
 
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#2 ·
Steel cased ammo doesn't always play well with fluted chambers. From one batch to another the cases can be different harnesses which can cause issues. Before tearing the rifle down and switching out more parts try running some brass cassed stuff through it and see if the problem continues or goes away.
 
#3 ·
Tula in my experience has always been lightly loaded, that combined with the higher bolt gap is probably your problem. If you just have a ton of Tula to get rid of you might put the old rollers back in, but if it were me I'd just switch ammo. Happy Thanksgiving.
 
#4 ·
Did it have under sized rollers to start with? If standard 8mm rollers were in there +2 rollers should not have brought up your gap that much. Anyway what was the gap when you bought the gun? I would want to figure out why there has been a significant drop in only 700 rounds if it was mine. I know that's not what you asked, just saying.
 
#8 ·
This. However I've been underwhelmed by Tulammo in the 7.62 x 39.. squibs, mostly. Never seen 7.62 NATO version locally, only online. In this caliber I stick with quality mil surp or handloads
 
#7 ·
Your bolt is not going into battery because there is no more bolt gap to lock rollers behind the trunion bumps. Its bouncing out on forward chambering. Be careful! If it goes off half in battery, you will feel and hear the difference. CALL Jeff asap
 
#9 ·
Okay guys, I thought I better clarify:

I never checked bolt gap until round 400 or so. Yes, I know that's bad.

When I checked it, it was right at .005" and it's held there for another 300 rounds. After doing some reading, it appears that's pretty tight. Thinking I would get better performance, I ordered some +4 rollers, not +2. I just checked, sorry!!

So, that brought it up to roughly .015 which I thought was supposedly a really good bolt gap. But, when I went to shoot the Tulammo that was working well before, I started to have terrible malfunctions. The rounds would only chamber during an "HK slap", upon firing and cycling, the bolt simply would not lock up all the way and was about 1/8" open. The hammer would still fall though, and would occasionally leave a very light mark on the primer.

At a firsthand glance, it appears that maybe this Tulammo doesn't have enough power to fully lock up. It ejects and feeds from the magazine just fine, but the bolt just won't lock up in the trunnion all the way.

I have no idea what is causing this, and it's a huge bummer for me. :( I've sank so much money into this gun... and it doesn't work now!
 
#17 ·
Try a different brand of ammo, (winchester or federal). Also, switch back to your old rollers and see if the problem goes away.
You can field strip the gun, hold the gun vertically, muzzle facing down, and drop the bolt carrier into the receiver. It should lock up into battery under it's own inertia.
 
#19 ·
In my experience the only major ammo failures I have ever had was with Tulammo. So I don't use it and when people post online about having gun issues and shoot Tulammo, the first thing I say is take the ammo out of the equation, clean the weapon and then shoot some proper brass cased ammo and see where you are. These days brass 7.62 NATO is cheap enough between 42 and 50 cents a round.

If your bolt gap disappears after replacing the rollers you could also have a cracked or soft bolt head. I had one out of the batch of "soft" bolt heads that PTR made in 2013 and it turned out it was cracked when my gap disappeared. Once replaced so far so good.
 
#20 ·
Thanks gang. I'll clean the gun real well and feed him so good Winchester shells.

If it don't work, I'll go back to the old rollers. Truth be told, I'll be scratching my head if it doesn't work with the quality brass stuff. Since my gap is .015, it should work no? Maybe it's just the weak junky Tula stuff I've got.
 
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