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9/19/2017 7:27:10 PM
Posted: 3/28/2006 4:23:37 PM EDT
[Last Edit: 3/29/2006 12:49:09 PM EDT by cobrasks]
Above and below the weld spots on the sides of my PTR-91s
receiver is a tiny dimple .
Very small ,maybe 5/1000 deep,and 1/8 of an inch long .
Depth wise ,it's a small fraction of the thickness of the sheetmetal,
And I'm wondering if it's enough to worry about.

My bolt gap went from .0016 to .0008 in around 1200 rounds
on this rifle.
I noticed that a tiny ,barely visible gap was between where the
trunnion and receiver are ,on the inside when it was new.
Right on the spot where the rollers lie.
This gap closed up ,and the dimples appeared on the outside.
The outline of the trunnion are also noticable
from the outside.

Since the gap closed ,the bolt gap hasn't changed in 500 rounds.

I've noticed other pictures of PTR-91s and true HKs with dimples
in the same exact location.
This rifle is accurate and flawlessly dependable,but it still makes
me wonder.

I can't currently post good enough pics to show it.

Can anyone else post close up pics of the sides of their 91
where the weld joint is for the trunnion/receiver meet up ?
(A Wide forearm would hide it)
Have you had this after your wear in ?

Do any of you experienced guys think this is something to worry
about and should be sent in for repair ,or is it fairly common
and nothing to worry about ?

I've been through hell over HK clones in the last 3 years ,so if
I don't need to send this in I would rather avoid it.

Many returns to various manufacturers for repairs.
The lady at the UPS counter knows me by first name.

Thanks for any pics or responses,I think I just need to
ease my worries about any possible future problems
after what I've been through over other clones.
Link Posted: 3/28/2006 6:20:26 PM EDT
I haven't fired mine yet so I won't be of much help yet. I will keep this post in mind and follow up in a week or so after some range time. I am going to watch this curiously as it evolves.
Link Posted: 4/2/2006 9:05:25 PM EDT
Here is a couple pics of mine below. About 1000 rnds through it so far. I noticed that the headspace on mine has dropped a bit on mine as well, from 0.017 to 0.012 in. Had posted about this a couple months back, and didn't get much response about it. One person said to not worry about it until it got below 0.010.

I posted a thread about this over at the HKPro boards, asking if anyone had ever monitored the decrease in headspace on a roller-lock during break in of a new weapon. Didn't get one response, which seems to indicate to me that people generally don't bother monitoring it.

As for you original question, the space between the receiver and the trunnion will not affect headspace. The only things that can affect headspace are (1) the barrel moving in or out of the trunnion, which is prevented by the barrel pin, (2) wear on the rollers which would take 1000's of rounds to wear down, (3) wear on the locking piece which may wear a little initially but these are very hard as well and have been tested as evidenced by the dimples on the sides, and (4) wear on the backside of the trunnion where the rollers come incontact with it.

I believe it is the fourth cause that is causing most of the initial decrease in headspace. JLD may not be getting the trunnions hardened enough, or they are hardened to spec, and it is just a given that they will wear a bit initially. As the backside of the trunnion is compressed by the rollers, the steel work-hardens, such that the more is wears, the harder it gets. As a result, eventually the initially decrease in headspace will slow down and seem to stop. It never really stops though, that is why there are +2 and +4 rollers.

I would chill out and stop worrying about your rifle. Afterall, this is supposed to a an enjoyable hobby, not an aggravation. Maybe give JLD a call and see what they have to say, but otherwise, I would just buy some +2 and +4 rollers, shoot the hell out of the rifle and bump up the rollers when you get below 0.005.



Link Posted: 4/3/2006 2:49:45 PM EDT
jason_H ,

Your rifle donesn't have the dimple I'm talking about .
If it does,it's to small to see.

Mine can be seen from accross the room,and is currently half the width
of the weld.
I talked to some HK smiths I know ,and they said it's
definately wrong.
I talked to Victor at JLD and after I described to him ,he said they
would repair or replace it.
No questions asked .
Most probably replace it .

That space I originally described is NOT supppose to exist.
Those parts are supposed to be against each other.

I like how Victor will send you a new gun ,instead of making you wait .
That's far better than the customer service I've gotten from a
few other HK builders that I won,t name at this time.
Link Posted: 4/4/2006 7:08:13 PM EDT

Originally Posted By cobrasks:
jason_H ,

Your rifle donesn't have the dimple I'm talking about .
If it does,it's to small to see.

Mine can be seen from accross the room,and is currently half the width
of the weld.
I talked to some HK smiths I know ,and they said it's
definately wrong.
I talked to Victor at JLD and after I described to him ,he said they
would repair or replace it.

No questions asked .
Most probably replace it .

That space I originally described is NOT supppose to exist.
Those parts are supposed to be against each other.

I like how Victor will send you a new gun ,instead of making you wait .
That's far better than the customer service I've gotten from a
few other HK builders that I won,t name at this time.



So, did Victor seem to think this was a recurring problem or did he even
go into detail about this issue ?

There are a lot of PTR's out there doing just fine and I doubt there is
a problem, but I think this might need to have some follow through info
"if" the bolt gap becomes a big issue in the future.

JMO

Link Posted: 4/5/2006 3:28:06 AM EDT
sounds like shitty truinion welds.

send it back,, i know some get dimples in the recessed area where teh rollers ride during recoil ect. mine has those along with a bunch of others. normally cuased by the lockers being locked out early due to recoil ect. weak Locking arm spring, ect. some times youll get them if you have a TFT or FTE atthe mag well when the bolt stops pushing the rollers out...
i had pic slong time ago,, see if i can find them.
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