Halo fits well as mentioned. Empire sport shot requires tape to snug up, as does a Revy. I don't own anything else.
OPBN, thank you for the close up photos!
Another question to anyone: On these feednecks, any troubles fitting modern hoppers? I know they
Pretty much. There is no "collar". It is a slotted feedtube with a clamp milled/cast directly onto/into the feedneck that is welded to the body.