Does anyone have a picture of the breech end of the barrel? I've been wondering what machining is necessary to get a poly barrel to fit? Does it have a transfer port? Or, can it be rotated to index the barrel?
Retrofit quite a few .... No thimble, requires a transfer port with a counter bore, 4 set screw flats all correctly clocked to keep the transfer port in correct position within receiver.
Barrels O.D. needs to be sized for receiver, leade cut into the bore accurately sized to get bolts end to go in & probes o-ring to seal.
If a machinist no problem .... drill press & files LOL ... nope
If barrel is machined right and spinning it once into receiver does not create any muzzle run out .. no reason to index.
If you machine the barrel to fit receiver and do a trial fit ... rotate it finding run out, then set any run out to clock high at 12:00 and then cut in transfer and flat your good to go.