300 blackout

[Benny]

I’m away from my data but I do remember the 150gr Remington PSPCL ended up at 2.220”. Being it was a flat base bullet, you can get away with it.
This was about the max length I was comfortable with of the bullet (or lack of) in the case for neck tension. The boat tail probably won’t work at this length.
I’m also doing a 150gr RN at 1.900”, same powder charge, in a 7 1/2” barrel.