Allen Engineering Mk12 SPR collar and adapter
Ops, Inc. #12 model
Perfect replacement for Ops Inc. #12, fits AES-5. This is for the Mk12 clone build, as well any other great rifle build.
Ron Allen builds these one by one by hand. He was the engineer that created the Ops Inc. collar and suppressor. Well worth the money for any precision 5.56 mm rifle build. Ron created the collar while working at Ops Inc. This is the exact same collar. If someone wants to argue otherwise, you might find something where a roll pin is .001" in a different spot, but I have not found it.
Included is the complete kit: Collar, flash hider and thread protector.