Thread: Thoughts on necks starting to split

Hey guys, anyone care to shear their opinion on necks starting to split on two times fired brass.


Rifle was cut to standard Sami spec 7mmSAUM

Loaded neck is .315 fired case is .320

22inch barrel shooting 162gr 3020fps with 61.8gr r26

Gun smith says it probably a case failure.

Cases are on the second fire and are Norma.

Nz ammo want all the brass back to send back for testing, witch will leave me with none for who knows how long. Rifle shoots pretty good so it doesn’t seem to effect accuracy

Brass too brittle

Anneal the necks properly to the shoulder junction and try a few again

And graphite powder the neck ID and projectile OD when assembling your ammo to stop galvanic corrosion from gripping the projectile, which sends a nasty shock through the neck upon projectile release

Happened to me with my 22-250 and Norma brass, 2x fired and it shat the bed. Didn't think to hit them up

Anneal every time.

NZ ammo want brass back...no worries,just send me some to use while you get the results back..thanks very muchly...job done.

+1 annealing each time. Might be able to restore unsplit brass with an anneal.

Are you using bushing dies?
If so, are you just sizing .001-.002 under .315 as any smaller will be over working and hardening your necks.
If they are standard dies then remove the expander and see how much the necks are being sized under .315 as some standard factory dies can size the brass way under what you would expect them to before the expander pulls back through.

And you could have got that speed with ADI2217

It’s far more available and temp stable than anything made by Alliant Reloader

Tried and couldn’t get that speed without pressure signs and tight bolt lift, the rifle also seemed to really like r26 and my goal was 162 at or just over 3000fps. If only I can get the brass to hold together

Originally Posted by Matt2308

Are you using bushing dies?
If so, are you just sizing .001-.002 under .315 as any smaller will be over working and hardening your necks.
If they are standard dies then remove the expander and see how much the necks are being sized under .315 as some standard factory dies can size the brass way under what you would expect them to before the expander pulls back through.

I’m using Redding comp dies. And full length. I’ll have a play tomorrow and see how much it’s working the brass with/without the expander

Originally Posted by Micky Duck

NZ ammo want brass back...no worries,just send me some to use while you get the results back..thanks very muchly...job done.

That would be ideal. But they don’t have any brass in stock

Originally Posted by Matt2308

Are you using bushing dies?
If so, are you just sizing .001-.002 under .315 as any smaller will be over working and hardening your necks.
If they are standard dies then remove the expander and see how much the necks are being sized under .315 as some standard factory dies can size the brass way under what you would expect them to before the expander pulls back through.

So I have run one through the die without the expander and it comes to 0.308

Originally Posted by dale

So I have run one through the die without the expander and it comes to 0.308

I don’t like using expander ball for that same reason it works the brass to much and need to change bushing size. I never anneal bass and get somewhere from 7 to 12 firings from 100 pieces of brass. Primer pockets give out before the necks and case wall do.

Originally Posted by dale

So I have run one through the die without the expander and it comes to 0.308

That’s a heap of extra and un-necessary sizing taking place and is certainly contributing to, if not the cause of your necks splitting.
Bushing dies with a .314 bushing would half the amount you are working your brass and extend its life considerably.

I would definitely suggest annealing every sizing with your current dies, but even this might not be enough to fix the issue.

Originally Posted by Matt2308

That’s a heap of extra and un-necessary sizing taking place and is certainly contributing to, if not the cause of your necks splitting.
Bushing dies with a .314 bushing would half the amount you are working your brass and extend its life considerably.

I would definitely suggest annealing every sizing with your current dies, but even this might not be enough to fix the issue.

Thanks for the info. Might look at new die.