Need help from Mauser Guru's

24 February 2015, 23:22

Tapper2

I found a Yugo Mauser that had been made into a .243 Win. I bought it for the action. I never fired it as a .243. (never fire a donor rifle) I made it into a .284 Win. The first time I fired it (factory ammo) the bolt was very difficult to lift. My first thought was receiver lug set back. It shown some signs of set back, so I trued the receiver lugs and the rear lug. It had no positive effect, the bolt still stuck after firing, smooth as silk before. What am I missing?

24 February 2015, 23:24

ramrod340

cocking ramp?

24 February 2015, 23:43

Toomany Tools

May want to check headspace again. And I'm curious: How did you "true the receiver lugs"?

25 February 2015, 02:57

Tapper2

quote:
Originally posted by Toomany Tools:
May want to check headspace again. And I'm curious: How did you "true the receiver lugs"?

I checked, the headspace is dead on.

What I did was locate the receiver in a four jaw and machined the receiver cam faces as well as the end of the receiver just to be sure they are parallel. I only took 2 or 3 thousands and they all cleaned up. It probably isn't the cocking cam as it is tight before the cam is engaged. True, I may have removed the case, however, that wouldn't show up in just one firing. I don't think it is a true Yugo as it looks to new and no marking. It is the right size. however.........Tom

25 February 2015, 03:55

dpcd

Check the firing pin internal interlock; I have had those that interfered with the bolt and needed their cams filed/angled a bit.
That is why I would remove the FP assy to try to isolate the problem.

25 February 2015, 06:00

Toomany Tools

Excess headspace sure as hell will make the bolt harder to open. The case stretches beyond its ability to recover, binding the bolt.

25 February 2015, 07:54

Aaron Little

Dry fire the gun and see if it duplicates the problem. If not...bring out the wallet.

25 February 2015, 09:12

eagle27

quote:
Originally posted by Tapper2:
I found a Yugo Mauser that had been made into a .243 Win. I bought it for the action. I never fired it as a .243. (never fire a donor rifle) I made it into a .284 Win. The first time I fired it (factory ammo) the bolt was very difficult to lift. My first thought was receiver lug set back. It shown some signs of set back, so I trued the receiver lugs and the rear lug. It had no positive effect, the bolt still stuck after firing, smooth as silk before. What am I missing?

Smooth as silk before what?

What happens if you dry fire? If smooth to open then nothing to do with the act of cocking. What happens when chambering a live round but not firing and then lifting the bolt, if smooth as silk then that eliminates an extractor nose problem. If the bolt is hard to lift only after firing a cartridge then has to be headspace/setback related. Not likely to be a cartridge pressure issue with factory ammo. What does a fired primer look like? Excessively flattened, backed out, flow into firing pin hole in bolt?

25 February 2015, 09:38

Tapper2

quote:
Originally posted by eagle27:
[QUOTE]Originally posted by Tapper2:
Smooth as silk before what?

What happens if you dry fire? If smooth to open then nothing to do with the act of cocking. What happens when chambering a live round but not firing and then lifting the bolt, if smooth as silk then that eliminates an extractor nose problem. If the bolt is hard to lift only after firing a cartridge then has to be headspace/setback related. Not likely to be a cartridge pressure issue with factory ammo. What does a fired primer look like? Excessively flattened, backed out, flow into firing pin hole in bolt?

It only happens after being fired. A dummy round doesn't do it after dry firing. The fired case, once it is removed, looks normal, no primer cratering or excessive flattening.

25 February 2015, 09:41

Tapper2

quote:
Originally posted by dpcd:
Check the firing pin internal interlock; I have had those that interfered with the bolt and needed their cams filed/angled a bit.
That is why I would remove the FP assy to try to isolate the problem.

I will give this a try and let you know what I find.

25 February 2015, 21:05

larrys

I've only seen it happen one time, but when you squared the receiver and cam faces, did you square the bolt face to these as well? I had a mauser that did the same thing and I finally had to square the bolt face. Highly unlikely, but it hapened to me. When the round goes into the chamber, it is just held there by the bolt. When it is fired, it then expands on to the bolt face as well as chamber. If the bolt face is not square to the chamber, then the round is sort of "cockeyed" after firing. Not much, but just enough to make extraction somewhat harder.

Like I said, probably a very remote possibility, but it happened to me.

26 February 2015, 01:28

Bobster

A rough chamber could do it. Makes it difficult to begin primary extraction. What do fired cases look like compared to unfired? Any scratches or hazing?

26 February 2015, 05:40

Tapper2

quote:
Originally posted by larrys:
I've only seen it happen one time, but when you squared the receiver and cam faces, did you square the bolt face to these as well? I had a mauser that did the same thing and I finally had to square the bolt face. Highly unlikely, but it hapened to me. When the round goes into the chamber, it is just held there by the bolt. When it is fired, it then expands on to the bolt face as well as chamber. If the bolt face is not square to the chamber, then the round is sort of "cockeyed" after firing. Not much, but just enough to make extraction somewhat harder.

Like I said, probably a very remote possibility, but it happened to me.

Larry, That is a possibility. I didn't check that, but I will now and report back....Tom

26 February 2015, 05:43

Tapper2

quote:
Originally posted by Bobster:
A rough chamber could do it. Makes it difficult to begin primary extraction. What do fired cases look like compared to unfired? Any scratches or hazing?

Bobster, I just check fired rounds and no frosting or scratches. I scoped the chamber and it looks good.

26 February 2015, 06:04

Bobster

Primary extraction in Mausers is initiated by the bolt root contacting the sloped edge of the rear bridge. Is yours contacting properly?

26 February 2015, 23:55

custombolt

Is it possible that a couple thousandths of case expansion could cause a drag on the extractor tip? Your .284's base of the case is wider than the .243 by about .030". May as well check extractor tip for excess flex (Duane Wiebe recommends .005" flex). A case darkened with a black magic marker will "tell the truth" after you fire one off and extract it. Raw brass doesn't show everything and a good magnifying glass can blow away a lot of smoke. Good luck.