Brent,

It uses a threaded barrel and a threaded pin to lock the barrel in place. The pin screws into the indent in the barrel. The threaded pin is on the left side of the action and turns almost 360 degrees to its stop.

[Linked Image from i.imgur.com]

[Linked Image from i.imgur.com]

Locked position [Linked Image from i.imgur.com]

Unlocked position [Linked Image from i.imgur.com]

Ken