Quote Originally Posted by T 20 View Post
I had to machine a small jig from some 25mm ID pipe to hold the Hawk back block in the lathe, then I drilled and tapped the central arbour 5/16 UNF in order to screw the guide into.
Sounds doable, and does not mess too much with the possibility of returning the gun to original shape. I might follow that route, thanks!

I see you extended the transfer port through the breech seal, was that necessary to get the compression high enough? I'm thinking a brass sleeve that only sleeves the port might help?