Quote Originally Posted by chanrobi View Post
Will these take standard remington barrels or proprietary to the shotgun?
From Hunting Gear Guy:


Rem 870 parts that fit the Ternion:
Extension tubes
Bolt
Trigger groups
The Ternion pump, bolt, bolt carrier went into the Rem 870 as a group, didn’t go the other way.
Magpul 870 stock (and other 870 stocks, I presume)
Rem 870 parts that didn’t fit the Ternion:
Barrels. The lug is in a different spot further up the mag tube. BUT, you can use the extension sleeve from the T870-1 to make 870 barrels work.
Bolt carriers are slightly different designs so the 870 bolt carrier won’t fit on the Ternion pump arms
The pump connecting arms of the rem 870 jammed up in the receiver of the Ternion