fireforming brass

In a properly cut AI chamber, close a factory round up in the chamber and squeeze the trigger. If you are usisng unfired brass and loading your forming rounds, load up some with a mid range powder charge and go fire them. Randy
 
You need at least a max charge for the original chambering to fully form an AI brass. Anything less will not fully form the shoulder angle.

Jack
 
with my 280AI I have a couple hundred bulk Remington bullets I use with standard 280 loads for fire forming... I've found the fire form loads are that accurate I use them for hunting ground hogs and such... makes burning up big bunches of powder and bullets so much more pleasureable...
 
Use a starting load or medium load of one of the faster powders for your cartridge and seat the bullets so they enter the rifleing or lands. The bolt will be hard to close but, your brass will fire form beautiful with the headspace being 0. When you open the bolt you will have a perfect A.I. cartridge case.
I've tried the K hornet, 30-06 AI, and currently use a 280 AI.
The factory stuff will form but, you will lose some due to neck splitting and they won't be 100% formed.
2 cents of trial and error and book work.
 
If your AI chamber is cut properly, you should be able to get good AI brass from factory ammo or from new hand loaded brass. A properly cut AI chamber has slightly shorter head space than a factory chamber in the same cartridge so you get a slight crush fit with factory ammo or new brass.

Some smiths have been known to cut an AI chamber in a factory barrel without setting the barrel back a thread. When that happens, you may have brass forming problems due to the chamber being too long.

Use a good, strong load if you hand load and you should be fine. It takes a good amount of pressure to fully expand the brass.

Good luck. - BCB
 
I've always used a max load to form with and Jack is right less won't form the shoulders sometimes won't even blow the case out. I take my AI rifles out varmit shooting as not to waste the load also don't be surprised if the load shoots real good. Well good luck.
 
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