PTR 91 and H&K91 Owners

will1122 · October 17, 2014, 08:19 PM

These rifles do not have a mechanism to cause the bolt to stay open when the last round is fired. How bad is the peening effect to the chamber area that the bolt contacts. Does it cause early wear ? Is there some other mechanism in place to soften the impact of the bolt ?

ttarp · October 17, 2014, 09:29 PM

The rifle was designed that way, and through thousands of rounds it causes no undue wear or damage.

will1122 · October 17, 2014, 10:09 PM

Thanks

**4V50 Gary** · October 19, 2014, 06:12 AM

The G-3 family of weapons was supposed to have a tracer in their second or third to the last round. That alerted the soldier that it was time to insert a fresh magazine. HK has made modifications to some guns to have a bolt hold open device.

tirod · October 19, 2014, 09:13 AM

Considering the weight of the BCG on my HK91, having it slam forward onto a hold open would seem to be even more abusive than simply chambering and locking closed with the rollers.

**44 AMP** · October 19, 2014, 11:05 AM

Considering how long this design has been around, and its use in military service, if there WAS any problem caused by the bolt slamming shut on an empty chamber, it would be widespread common knowledge by now.

I wouldn't loose any sleep over it, personally.

ttarp · October 19, 2014, 12:41 PM

The issue with a bolt hold open on these guns is the rollers in the bolt head will try to slam outwards into their locked position (I know its roller delayed blowback and not roller locked, but you know what I mean) when the carrier stops, and this causes "roller marks" and damages the receiver. Best to just use the gun the way it was designed, if a bolt hold open is a must, this isn't the rifle for you.

Snyper · October 20, 2014, 04:30 PM

Quote:

How bad is the peening effect to the chamber area that the bolt contacts.

That only happens with rimfires, since a centerfire's pin doesn't hit anything if the chanber is empty

Sweet Shooter · October 20, 2014, 05:22 PM

Quote:

Snyper
Quote:
How bad is the peening effect to the chamber area that the bolt contacts.
That only happens with rimfires, since a centerfire's pin doesn't hit anything if the chanber is empty

He's asking about the bolt-head lugs—not the firing pin—hitting the breech-face.
He has some good answers.
-SS-

Snyper · October 21, 2014, 05:22 AM

Quote:

He's asking about the bolt-head lugs—not the firing pin

Yeah, I misunderstood the question

Peening is not really a problem though
HK's (and most clones) are some of the most durable guns made

October 17, 2014, 08:19 PM	#1
will1122 Junior Member Join Date: October 6, 2014 Posts: 7	PTR 91 and H&K91 Owners These rifles do not have a mechanism to cause the bolt to stay open when the last round is fired. How bad is the peening effect to the chamber area that the bolt contacts. Does it cause early wear ? Is there some other mechanism in place to soften the impact of the bolt ?

October 19, 2014, 06:12 AM	#4
4V50 Gary Staff Join Date: November 2, 1998 Location: Colorado Posts: 21,832	The G-3 family of weapons was supposed to have a tracer in their second or third to the last round. That alerted the soldier that it was time to insert a fresh magazine. HK has made modifications to some guns to have a bolt hold open device. __________________ Vigilantibus et non dormientibus jura subveniunt. *Molon Labe!*

October 19, 2014, 11:05 AM	#6
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,817	Considering how long this design has been around, and its use in military service, if there WAS any problem caused by the bolt slamming shut on an empty chamber, it would be widespread common knowledge by now. I wouldn't loose any sleep over it, personally. __________________ All else being equal (and it almost never is) bigger bullets tend to work better.

October 17, 2014, 09:29 PM	#2
ttarp Senior Member Join Date: January 4, 2013 Posts: 888	The rifle was designed that way, and through thousands of rounds it causes no undue wear or damage.

October 17, 2014, 10:09 PM	#3
will1122 Junior Member Join Date: October 6, 2014 Posts: 7	Thanks

October 19, 2014, 09:13 AM	#5
tirod Junior member Join Date: January 21, 2009 Posts: 1,672	Considering the weight of the BCG on my HK91, having it slam forward onto a hold open would seem to be even more abusive than simply chambering and locking closed with the rollers.

October 19, 2014, 12:41 PM	#7
ttarp Senior Member Join Date: January 4, 2013 Posts: 888	The issue with a bolt hold open on these guns is the rollers in the bolt head will try to slam outwards into their locked position (I know its roller delayed blowback and not roller locked, but you know what I mean) when the carrier stops, and this causes "roller marks" and damages the receiver. Best to just use the gun the way it was designed, if a bolt hold open is a must, this isn't the rifle for you.