Lesson learned?

[Wayne Smith]

I have my 25 Krag AI barrel and am forming brass for it. I am getting about a 50% failure rate even with annealed cases. I noticed that the neck length criteria for each cartridge is 1 caliber - thus .308" for the 30 US and .257" for the 25 Krag. I had been sizing the necks the full length, or .308". The next bunch I'll size the necks down .257" and see if I have the same failure rate.

[country gent]

Size the necks and shoulder back just enough to allow chambering of the round. Ideally you want to feel a little resistance as the bolt cams over closing. this holds the case in alighnment and position on the first firing.

On cases where the shoulder is moved forward this results in a false shoulder in the right spot to hold case snug and in position. Most of the AI cases had the shoulder neck the same but the shoulder was steeper resulting in a different shoulder datum location. Some even go so far as to neck up a caliber size and neck back down to gain more false shoulder area.

[17nut]

Or you could simply apply an O-ring in front of the rim at first firing.
That will hold the case firmly back against the boltface at firing/forming.

[EDG]

It is better to stop against the shoulder in the chamber.
Using Krag brass in a .303 Brit sometimes separates the case with the first fire forming shot.

[Wayne Smith]

I lost all of mine to shoulder/neck splits, not base splits.

[EDG]

You might try annealing your cases or using new or fresh once fired brass. I have made hundreds of 6.5X53R cases from new or once fired and annealed .303 cases and never lost one to fireforming.

I lost all of mine to shoulder/neck splits, not base splits.

[Wayne Smith]

These are supposed to be once fired! I have 50 new as well. The last series were annealed - neck and shoulder in my lead pot. I'm pretty sure that the combination of pushing the shoulder so far forward is the problem - when I neck size the rest 1 caliber length I think I'll have the problem solved.

[rr2241tx]

Adequately annealed brass should blow out to the AI chamber with little or no case failures. 50% failures suggests that your annealing is insufficient. Work hardening the .050 of neck that is to become the new shoulder certainly isn't helping so raising your neck sizing die will help some but won't substitute for better control of your annealing.

[Soundguy]

Or you could simply apply an O-ring in front of the rim at first firing.
That will hold the case firmly back against the boltface at firing/forming.

neat idea. when you do yours, do you use a small bullseye or unique charge and then a filler and a wax plug, or something totally different?

thanks