Failures in fireforming

I was recently forming 7-30 Waters from 30-30 using the COW method. Why might I be getting these failures? Are the other 80 cases ok? They look ok on the outside.

Brass was once fired Winchester. All were double annealed…pre/post fl sizing to set false shoulder.

The brass was fired in a chamber having excessive clearance, and then if sized way back down (before your firing), it work hardened.
Brass only stretches just so far.

But if it was just the chamber why would they have done it in different spots??? Not trying to argue just want to understand.

Wow

I will really like to know what is going on here

I would venture the saying 'some brass is made to reuse....some isnt'...

Look at the 4th from top...it looks like it nearly created another fissure hole at the head...

The brass was fired in a 30-30 Win of unknown origin or chamber. I'm guessing range rental somewhere.

Then I bought it when new 30-30 was unobtanium. I annealed neck and shoulder pretty good, FL sized to create a false shoulder and then annealed again. Then fireformed with 5.5gr of titegroup and COW.

Maybe I could of got 99% of the forming done at 4 gr, but I normally bump it up until I get a perfect shoulder.

I don't think the 4th down had an issue at the base, but maybe.

I guess I'm wondering what to do with the other 80. I'm going to try load development. If they keep doing this, I with toss in the trash and start over. I have the barrel coming back in a couple days and I really want to develop a load, but the brass will need to go 3 more load cycles at minimum to get through hunting season.

victor3ranger said:

I will really like to know what is going on here

Click to expand...

Me too!

Looks to be brittle brass, my 30-30 is plagued with excessive headspace, so I get 2 firings and the third sizing always ends up in head separations. I guess the tolerances in 1906 weren't the best…
Have seen this quite a bit from old hardened brass, had an entire lot of Winchester 44-40 brass crack upon firing like yours and it etched the chamber…

Cheers.

Ive had a few split and always winchester. I used to hs my old 30-30 off the shoulder and brass lasted a lot longer. I sold it and the guy made a 7 waters out of it