Gunsmithing PTR 91 Stovepipe Jams

Necromancer71

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Minuteman
Aug 2, 2010
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I have a new PTR91 that is plagued with stovepipe jams - straight out of the box. Chamber is clean. Headspace correct. Extractor tight. This occurs at about every second or third firing and occurs with any brand ammo and all bullet weights I've tried. Empty round is partially extracted, turned vertical, but does not clear. The next live round is partially chambered and gets bent in the process. Before I return it I was wondering if there is something others have seen and might be easily remedied. Like all HK-based rifles of this type, the brass is mangled but in this case the mouth is slammed shut and may be bouncing around instead of clearing the weapon?
 
Re: PTR 91 Stovepipe Jams

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BigBoss0311</div><div class="ubbcode-body">The hkpro forum may have a little more insight to your problem. Post your question in the clone section over there.</div></div>
+1
There have been some issues I know with the barrels not having good enough (deep enough) fluting. This causes poor extraction. The case should come out of that rifle like you threw it overhand. My brass gets kicked about 20 feet in a nice little pile.
there is a video of someone taking the extractor out of the bolt head and the thing STILL extracted due to the fluting.

Edit forgot to ask
Can you post a picture of the fired brass? The flutes should be deep you can feel them real easy with your finger.
 
Re: PTR 91 Stovepipe Jams

Thanks. Great input as the brass that does make it out of the weapon are laying in in the immediate area, not in the next zip code as one would expect.
 
Re: PTR 91 Stovepipe Jams

M14 G3 FNFAL and there clones are battle rifles, and should all work 100% out of the box, get your money back or send it back for warrenty work
 
Re: PTR 91 Stovepipe Jams

Any HK 91 or 93 or clone of will spit the brass out farther than anything I have ever shot. If it don't it's broke and I would agree with 427Cobra on sending it back or get your money back immediatly.
smile.gif

Search youtube for a video and you will be able to see how far to expect them to fling the brass
 
Re: PTR 91 Stovepipe Jams

I know you said your headspace was ok, but buy some +1 or +2 rollers for the bolt. They're cheap and easy to switch in and out. Try the +1's first them the +2's rollers. I had the same problems with my Portugese HK91 based rifle and the oversized rollers fixed it.
 
Re: PTR 91 Stovepipe Jams

I would check the ejector / trigger group height if its not ejecting. It sounds like your ejector might be low and not clearing the fired case.
 
Re: PTR 91 Stovepipe Jams

A recent ejection problem at work with an MP5 was remedied by replacing the extractor... no tweaking, just swapping it out. There is quite a bit of unique geometry goin on in the HKs... be careful what you modify and be sure to check your bolt gap.
 
Re: PTR 91 Stovepipe Jams

This is a new rifle right? Don't put + rollers in it.
Here is a vid that shows how well an HK will extract EVEN without an extractor. An extractor just may cure the problem as JNixon said but you should have them fix it as you could have other issues.
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Here is how it works
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bolt gap should be anywhere between .004 to .020 unless it has been ground or the trunnion is not set correctly. Check out the first video.
All in all you need to send it in or get them to give you a different rifle. DON'T MESS WITH IT...
 
Re: PTR 91 Stovepipe Jams

Have you used South African or other Ammo which uses Burdine Primer. The company warns against the use of this ammo. Have you cleaned the gun and if you have used this primer, make sure your flutes are clean of the tar this primer creates.
 
Re: PTR 91 Stovepipe Jams

The primer has nothing to do with the tar. It's the sealant commonly used at the case mouths on military ammo. Winchester white boxes marked 7.62 is listed by PTR as an identified ammo causing this problem and it's boxer primed not berdan.