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PTR91 still getting heavy recoil

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I have a PTR91-GIR that I’ve had, new since 2018. The rifle probably has roughly 1200-1400 rounds through it. After initial break in it has run good overall. However, when I was cleaning it earlier this year, I noticed very subtle roller deformations at the rear of the receiver. At that time, bolt gap was reading .008”. I contacted PTR and they recommended sending it back which I did. Once I got it back, I checked bolt gap before firing and it read .012”. They also mentioned the dents in the receiver rails were fine and nothing to be concerned about. Now the dents are getting worse after 150 rounds with visible bulging on the outside of the receiver. Bolt gap is now .010”(.011” will go but with decent resistance).
Is there something I’m missing here? If I understand correctly, a tighter gap will tame recoil a bit. Additionally, this is still within spec. The LP is stamped 45° and the buffer is a B. Springfield new unit. Could a tired recoil spring be the culprit? I’m not entirely sure how to test a recoil spring. One last point, this rifle has been getting light strikes again from not going into battery. Seems to happen once every 2-3 mags. When it does happen, I’ll charge the rifle to attempt to clear the malfunction and the bullet will strip and remain lodged in the chamber almost every time which is really annoying not to mention dangerous. If it’s not going into battery maybe this could be indicative of a tired recoil spring however, it’s still a bear to charge. Always has been. So much so it takes a violent jerk to get it going and is impossible to do prone.
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22 years ago I bought a CENTURY built G3 clone and it has a very tame recoil, compared to that of a pre-89 HK91that a buddy of mine had.

it all was due to the muzzle brake CENTURY installed on it. when the AW ban ended, everybody was itching to remove the brake to put a FH on it..............not me :)

now, I don't think that recoil could be issue with roller dent on your receiver, use the board search feature, I'm 100 percent sure that roller dents was disused before
 

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The buffer I have is a Bill Springfield unit. That was one of the first things I changed. Is PTR still using their trunnions or RCM’s?
I don't trust the Bill Springfield stuff. It is very possible that it is causing the issue. The bolt needs time to slow down from the recoil spring before it hits the hard "brake" of the buffer. I would swap out the buffers and see if you continue to get any dents.
 

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Discussion Starter · #6 ·
I don't trust the Bill Springfield stuff. It is very possible that it is causing the issue. The bolt needs time to slow down from the recoil spring before it hits the hard "brake" of the buffer. I would swap out the buffers and see if you continue to get any dents.
Is there something specific about Bill Springfield’s stuff I should be concerned about? I’ve gotten a few of his trigger jobs and he’s always been responsive and the triggers work well albeit unconventional.

I have some surplus buffers laying around, I’ll swap one in. Kinda thinking the recoil spring might be toast as well considering it’s also a surplus part.
 

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(SNIP)
I have some surplus buffers laying around, I’ll swap one in. Kinda thinking the recoil spring might be toast as well considering it’s also a surplus part.
It does sound like that could be the issue.

I would also replace the extractor spring.

My PTR91 has the Bill Springfield buffer spring and plunger, and it hasn't been a problem.
 

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Is there something specific about Bill Springfield’s stuff I should be concerned about? I’ve gotten a few of his trigger jobs and he’s always been responsive and the triggers work well albeit unconventional.

I have some surplus buffers laying around, I’ll swap one in. Kinda thinking the recoil spring might be toast as well considering it’s also a surplus part.
There's no way that I can picture where the BS buffer, or even the PCS buffer, or finally any of the four types of factory HK buffer can cause the issues you are having. Seeing as how the rifle is still under warranty I'd send it back to PTR again. Once you muck with it they are off the hook and you don't want to be responsible for replacing something like a trunnion. Tell them your concerns, show them your pics, and ask them nicely to take another look at the rifle.
 

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I don't trust the Bill Springfield stuff. It is very possible that it is causing the issue. The bolt needs time to slow down from the recoil spring before it hits the hard "brake" of the buffer. I would swap out the buffers and see if you continue to get any dents.
The first I've heard of this . Bill has many thousands of these out in the field for 10 years or more. I had one in my HK91 that made a big difference.
 

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I don't trust the Bill Springfield stuff. It is very possible that it is causing the issue. The bolt needs time to slow down from the recoil spring before it hits the hard "brake" of the buffer. I would swap out the buffers and see if you continue to get any dents.
Compared to the stock set-up, the longer plunger and longer spring travel and lighter spring rate would seem like an improvement over the original, as far as absorbing recoil efficiently goes.

The original design, with the copper between the coils, never seemed like a great idea to me.

There is some conflicting information about exactly what the copper pieces are designed to do.
 

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Compared to the stock set-up, the longer plunger and longer spring travel and lighter spring rate would seem like an improvement over the original, as far as absorbing recoil efficiently goes.

The original design, with the copper between the coils, never seemed like a great idea to me.

There is some conflicting information about exactly what the copper pieces are designed to do.
There is a reason the German heavy buffers (and I believe the Parabellum one also) for G3 and 91 are "two stage". The aftermarket ones made by Bill Springfield and HKPARTS are single stage. I realized looking back at photos that my PTR got roller dents after I installed BS's retractable stock buffer on my gun, even though I did it 100% to the instructions provided on his site.
I won't use anything other than the Choate buffer and H&K buffers now. It's not worth the risk. Simply increasing spring strength and having a longer plunger is not the solution. It is essentially the same as the bolt slamming into the back of the plate, it's probably going to make the rollers pop out.

When I got my BS buffer it looked like he had hit the front of the piston with a belt sander. Had an uneven face. Might be that he sent me a busted one, too.

The original buffer has the copper pieces for additional braking but mostly for the rifled grenades. Your miles may vary.
 

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There is some conflicting information about exactly what the copper pieces are designed to do.
The only conflicting information is people dont know how they work.

They wedge the in the buffer when the spring collapses causing more friction=stronger buffer.

AFA the BS buffer I would toss it. In my early HK years tried using it. Mistake.
 

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They also mentioned the dents in the receiver rails were fine and nothing to be concerned about. Now the dents are getting worse after 150 rounds with visible bulging on the outside of the receiver. Bolt gap is now .010”(.011” will go but with decent resistance).
Is there something I’m missing here?
You mean ptr sent out another junk rifle-impossible. Most HK guys know denting is not a good sign and can destroy a receiver.

1 sh!tcan that buffer, I would get a 21e stock/buffer or at least a german buffer.
2. get a german recoil spring and new locking lever spring. I would even go as far as using a 21e LL spring. LL spring help to slow the gun down (take energy form the bolt movement.
3. new extractor spring
4. Maybe even get a new LL, PTR is not know for great parts, I would check it for wear.
5. If that doesn't work get a new LP


If ptrs monkeys say the denting is fine I would not send anything back to them.
 

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You mean ptr sent out another junk rifle-impossible. Most HK guys know denting is not a good sign and can destroy a receiver.

1 sh!tcan that buffer, I would get a 21e stock/buffer or at least a german buffer.
2. get a german recoil spring and new locking lever spring. I would even go as far as using a 21e LL spring. LL spring help to slow the gun down (take energy form the bolt movement.
3. new extractor spring
4. Maybe even get a new LL, PTR is not know for great parts, I would check it for wear.
5. If that doesn't work get a new LP


If ptrs monkeys say the denting is fine I would not send anything back to them.
100% concur with everything you wrote...problem is: you start doing that and you easily bolt on more $$ than that PTR cost in the first place...and now you are in shooter grade HK91 territory. HK parts are crazy expensive...especially anything German and 21e
 

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If ptrs monkeys say the denting is fine I would not send anything back to them.
I understand your concern and generally agree. I recommend return to PTR in this case for multiple reasons. 1) They built it. 2) It's not a German rifle so there's no need to over protect it. 3) It's their warranty, they will honor it given a chance. 3) If they honor the warranty and work on the gun and it fails, it's on them. They'll be on the hook for making it right, legally.
The owner has no responsibility to protect the rifle from PTR or repair the rifle as long as it has manufacturers warranty, only to request warranty be performed.
I agree, if the gun was German and PTR was a repair center I'd protect it, also, and look for someone who knew the rifles intimately better than PTR seems to. But this isn't a German gun and the owner should not be out a dime if it fails under the warranty repair of PTR.
 
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You mean ptr sent out another junk rifle-impossible. Most HK guys know denting is not a good sign and can destroy a receiver.

1 sh!tcan that buffer, I would get a 21e stock/buffer or at least a german buffer.
2. get a german recoil spring and new locking lever spring. I would even go as far as using a 21e LL spring. LL spring help to slow the gun down (take energy form the bolt movement.
3. new extractor spring
4. Maybe even get a new LL, PTR is not know for great parts, I would check it for wear.
5. If that doesn't work get a new LP


If ptrs monkeys say the denting is fine I would not send anything back to them.
This ^

I would replace that buffer before your receiver is destroyed.

I have a PTR91 but mine is older (7+ years). Almost all original HK parts. IMHO not to bash PTR but they have done some questionable things over the years.

For example - the buffer has a bolt on the rear end that is supposed to be screwed into a sleeve in the stock. PTR completely removed the sleeve in the stock and said thats its not needed along with with the bolt in the rear. Really?
Without the sleeve the buffer is free floating n the middle of the stock with no support around it.

Than why did HK put it there in the first place? Does PTR know more than HK? I doubt it.

I have found that people say they know HK roller locked guns but in reality dont. There are a few HK gunsmiths on this forum that know their stuff. You might want to talk to them before you head down the rabbit hole.

One thing is for sure, the denting is not normal.
 

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This ^

I would replace that buffer before your receiver is destroyed.

I have a PTR91 but mine is older (7+ years). Almost all original HK parts. IMHO not to bash PTR but they have done some questionable things over the years.

For example - the buffer has a bolt on the rear end that is supposed to be screwed into a sleeve in the stock. PTR completely removed the sleeve in the stock and said thats its not needed along with with the bolt in the rear. Really?
Without the sleeve the buffer is free floating n the middle of the stock with no support around it.

Than why did HK put it there in the first place? Does PTR know more than HK? I doubt it.

I have found that people say they know HK roller locked guns but in reality dont. There are a few HK gunsmiths on this forum that know their stuff. You might want to talk to them before you head down the rabbit hole.

One thing is for sure, the denting is not normal.
I've wondered since I first found out years ago why PTR omitted the bolt in the middle of the buffer when they designed their stock. Always bugged me. Probably a money saving move but not the best idea, methinks.
 
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