Double check prices on 300NM before you move forward! It's ridiculous right now - like $6/round. I have a factory 300NM and bought
a 300WM barrel last week to cut ammo costs by 60-80%. I'd also love to know more about builder kits for the future, though!
It's the rear taper on the muzzle device. Unlike some dual taper designs, this isn't used for alignment. Instead, the collar on the suppressor uses the surface to effectively stop rotation. The suppressor has very little wiggle on the threads and seems to fully mate/align in the last 75% of a turn with absolutely no movement that I can detect. With the collar engaged, I can only unscrew the suppressor maybe 10% of a turn by hand before I lose my grip. Basically jamming the collar into the rear taper at this point which you can see in the wear marks on my muzzle.
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