Thread: 223 mag box length

All factory mag boxes will allow a SAAMI COAL of 2.250" or 59mm +/-.

If you want to run heavies and your chambering allows for it (long throat / freebore) then you get additional performance by seating said heavies out a little further.

Tikka's are renowned for long throats and the mags can be elongated using a Dremel and some sandpaper.

If you are going to run a shorter barrel, I think this will negate the additional performance you are expecting.

My last howa mini with a 16" barrel ran the 77 SMK belmont OFC load at 2550 fps.

My current 223 is 18" with a can and I'm expecting 2600 fps 'ish'.