Thoughts?

Apr 9, 2017
82
2
8
Las Cruces, NM
#1
So I had a 22-6mm Remington built on an old M77 (tang safety) action with a Krieger barrel (8 twist). All the work was done by a smith who I had yet to have any reason not to trust the work. After the work was done, I shot the 80 grain ELD Match (48.0 grains of H1000, all same lot, set at .010" off the lands), using Hdy 6mm rem brass, for a little while. It was working great too. When I neck the brass down, the shoulders aren't touched and I use headspace gauges to set my dies. Anyways, on the 3rd firing of the brass, one of the pieces split about 1" from the base all the way around. It was a very precise, laser like cut. After, the gun is failing to hold 3" at 50 yards and bulges the cases about .016" about .25" from the base. I have a lot of ideas as to what had happened but maybe someone here can help narrow it down for me. All charges are weighed on a balance beam scale, calibrated before and after loading.

If there is any other information someone needs, please let me know. I keep very good records.
 
Likes: Downtown
Apr 9, 2017
82
2
8
Las Cruces, NM
#2
I had to back the loads way down, to at or just below, listed starting. The gun is still bulging cases and showing pressure, which it didn't do before. The cases were growing .009-.017" per firing after the incident. Before they were still growing, but around .005-.007". With the lack of any real shoulder angle on the case, perhaps this is unavoidable but .017 is ridiculous.
 

EXTREMEPREJUDICE

Online Training Member
Oct 21, 2008
1,676
45
48
SE MICHIGAN
#3
Since you have headspace gauges check your rifle. Do you have a field gauge? If it's in tolerance I would be guessing you are oversizing your fired brass. A case mic or comparator is a much better tool to use to set your dies, rather than headspace gauges..........my opinion of course.
 
Likes: Jarridmoore
May 27, 2009
21
1
3
34
#6
So brand-new brass grows 0.017" using the hornady comparator?

You say you're not touching the shoulder when re-sizing. What kind of die are you using?

How far are you bumping the shoulder back when re-sizing? It shouldn't be able to grow any more than you bump it back...

It sounds like the shoulder isn't expanding properly on the first firing. Are you leaving a false shoulder so that the bolt closes with a little pressure after necking down to .22?
 

Mordamer

Professional Know It All
May 11, 2010
548
92
28
Hooker, OK
#7
If you are "bulging" cases just above the head you need to stop firing the gun immediately. Take it back to the gunsmith and give him a chance to look it over. Take a bunch of the fired cases and virgin cases with you if you can. If this was a barrel I chambered I would certainly want to examine it myself to determine the problem. It sounds like something has stretched or changed as far as chamber dimensions. If this is the case, then the gun is unsafe to shoot until a competent gunsmith has examined it and given it his blessing.
 
Apr 9, 2017
82
2
8
Las Cruces, NM
#12
It didn't damage the firearm in a way that I could notice. The bolt opened normally, other than the feeling of not pulling a normal case out of the chamber. The rest of the case fell out by tapping the butt of the stock lightly. No damage to the bolt.
 
Apr 9, 2017
82
2
8
Las Cruces, NM
#13
The chamber was pretty black but a casting was done and was given the all clear by the smith. No damage was noted to the chamber. Then the bulging of cases started showing up. The case goes from about .463 at the base to about .475 about .250 up the case. Neck tension on my cases is between .001 and .002. Dies are clean polished and undamaged.

It's all very weird. The smith is taking care of me on it, but I want an explanation and so does he. There is a reason for all of this. We both have ideas and are just narrowing it down via process of elimination.
 
Apr 9, 2017
82
2
8
Las Cruces, NM
#21
Yes, the barrel unscrewed by hand. As far as the cause, I have heard a few things, many amount to this is why some gunsmiths will not work on this model of gun in particular (something with the way the receivers were made and not very strong, especially for a round like this). Regardless, it a paperweight now and some of the parts are now for sale.
 
Top Bottom