Group Buy 300 Blackout. (completed)

[Tack Driver]

Barrel Cost.

1/8 twist $110
1/7 twist $100

These are the same barrels (M4 profile 16") as the uppers. No stainless option.

Who makes the barrels, respond from White River Armory is:
As for the barrels, we have a national company make them for us to our specifications.

Help me out here. Humor me.

Carbine gas?
Fixed A2 FSB? F marked? Sans post, detent, spring?
Barrel nut? Handguard retainer?