JJ wrote:FJ540 wrote:1.368 is Max length for the blackout Larry.
But 1.37 would be consistent with a 300/221 chamber as they are chambered to 1.40 IIRC
Given the longer leade, and the fact the round headspaces on the shoulder - without actually casting the chamber (something I'd like to do), it's hard to say what is really too long. Some guys are finding they're sticking rounds if their brass is too long though. It acts like a roll crimp when the bolt slams shut. While that might not be overtly dangerous, it's certainly not ideal.
JJ is correct though - .002 isn't likely to matter. What I was getting at was the fact your brass will grow the first time you shoot it, and then it'll be doubly as over length. Larry has told me he's working on the blackout spec, so that's why I pointed that out. Hornady has a new load section in the updated manual which covers both whisper and blackout, and they fail to call out the spec for the blackout.