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rmw1
03-12-2008, 10:47 AM
Good Morning,
I am posting this for a friend, it has us, and few others, perplexed, and I figured someone on this forum may have experienced this issue or have some suggestion as to what is happening.

He has a Rem 700 BDL Varmint 24" HB in .22-.250. Background, all cases (mixed headstamp) have been fired in this gun, all cases are in good shape and clean, all cases are trimmed to minimum OAL, loads are 34.0 gr. IMR 4895 with 52 gr. Sierra Matchking Moly-Coated. Ater firing, the inside neck diameter is approximately .222", actually smaller than the bullet diameter. To try and overcome this problem he has tried the following: 1) Neck reamed cases to .225" and sized with Lee Collet Die, results still .222" after firing, 2) Repeated the steps above, results still the same, neck thickness has went from .013" to .008". The cases do not show signs of excessive pressure, and chamber normally.

Any help would be appreciated.

Thanks
Dick

karls42
03-12-2008, 01:12 PM
Hard, overworked brass. It springs back to the original neck sized diameter after firing.

Larry Elliott
03-12-2008, 02:36 PM
I've seen necks do that with loads that were fairly mild as I think 34 gr 4895 is with a 52 gr bullet. Hard necks can contribute to the problem. When the charge is increased to closer to a max load a bullet will pretty easily enter the neck of a fired case.

If extraction is normal and there are no other signs of high pressures it's not a problem. You're unlikely to have necks that are too thick for a factory chamber.

Dennis Sorensen
03-12-2008, 03:25 PM
The previous posts covered it...

In order for brass to expand and stay expanded requires that the brass expands beyond it's elastic ability... two things can prevent this from happening... one is fairly hard brass and the other is neck clearance... your brass can be perfectly correct and your chamber can be as well and this can still occur and is common and normal; every reloader will experience it to some extent, sometime...

Mixing up various makes of brass is not a good procedure though. You should treat each one as a different load until proven differently.

BJS6
03-12-2008, 04:31 PM
Sometimes just the end of the neck can spring back, kind of curl over, which makes the end of the neck to small to easily slide a bullet in.

Also how are you measuring the 0.222, it is hard to measure the inside of the neck easily.

If you actually try and seat a bullet properly will it seat with normal seating force or is it quite loose by comparison to a sized case ?

I'd get some fresh brass and see what happens, I'd also give up on the neck reaming, that will help nothing at all.

Just Mike
03-12-2008, 10:14 PM
My first thoughts were how are you measuring the inside diam of the cases. And is your measuring insturment accurate?

Just my WAG.

Yukon Kid
03-13-2008, 02:11 PM
Make a cast of your chamber to just make sure you are dealing with an unaltered chamber !!!!

rmw1
03-14-2008, 12:00 PM
Good Morning,
Thanks for all of the good advice. Went with the pressure idea first. Jacked the pressure up with standard jacketed bullets, problem went away.
Thanks
Dick