Can someone tell me why the 30-30 AI has a .350 neck length? Would there be fireforming issues w/ a .308 neck like the 7-30 Waters? I want to get into handloading and my first caliber will be an improved 30-30 as I want to have my Marlin 336 rechambered. Any info/suggestions would be appreciated.

Because that is the way the designer wanted it...



Blow out the case body, slap a 40-degree shoulder on it, and shorten the neck...

But the 30-30 headspaces on the rim. The 30-30AI neck length, at .350, is considerably shorter than the 30-30, but I guess I'd like to have an even shorter neck of .308 or so to maximize case capacity. Is it because the web stretches too far if the shoulder is pushed too far forward? I've read that some people use 7-30 Waters brass necked up to .308 to fireform, but I'd rather use 30-30 brass for safety and to use factory ammo. I'm new at this, forgive me.

The whole idea of the Ackley improved line is that the headspacing data line stays the same so that you can always fire factory ammo in it. Sure, the velocity with factory ammo will be lower and point of impact may be different, but the gun will safely fire. If you move the neck up like in the 7x30 you can't fire form with factory ammo anymore.

regards,
graycg

PS- the 30-30 improved is well worth the change, it really puts the 30-30 into the 300 savage league safely.