Got my Fireball working

[bybon]

I bought this barrel a number of years ago and had trouble getting it to run reliably going supersonic. I thought it was time to see if I could begin again and make this caliber run. As far as I can remember, It is a M1S upper. I bought it over six years ago.

Last week I tried a number of different bullets ranging from 110 gr RN to 180 gr. All worked well, even the 110 gr carbine bullet (mostly). Most of my cases had been cut to an OAL of 1.400. I did have some 221 Fireball cases I had converted over to handle to 300.

With that as background, here is my question. I checked the barrel's chamber and it has been cut to an OAL of 1.445. Is there a need for me to cut the existing 1.400 cases down to 1.355? Thanks

[rsilvers]

Not if you just want to shoot your ammo in your gun.

By the way, 1.355 seems to be an oft-quoted 'trim length' but that is not the same as a max length.

300 AAC BLACKOUT has a max length of 1.368.

[bybon]

Thank you rsilvers. Only one rifle at this time.
On a side note, I have enjoyed your info regarding your new cartridge. I trust things will go well for you and it. Again, thanks.

[snipecatcher]

My chamber is 1.4xx too, so I thought I'd leave some of my brass long to make less of a jump. The first one I tried to form was crushed in my Redding die, as it is a crimp die and set up for a shorter length. I just keep them at 1.35 now.
-Dan

[rsilvers]

By the way, Rem factory 300 BLK brass is generally 1.36