Barrel back ID - powerlyte?

[mercpb]

Another edition of "not really worried about value just don't know what it is..."

Barrel back, stainless, autococker thread. Has aggressive step mill in the back suggesting it takes powerlyte-style inserts.

Really feels like powerlyte I just cant find a match.
comically, spyder barrels fit the front threads.... it came to me with a spyder barrel for a "tip"

[Ecapnation]

No, this is the stock defiant one barrel that uses otp inserts

[scottieb]

I never realized the front of the old Defiant barrels were Spyder threaded. That's neat.

[Reflex0283]

The original Defiant is autococker threaded

[mercpb]

Yes the back is AC
The FRONT is spyder threaded (not perfectly where you can use a spyder barrel as a tip but, you can screw one on)