Possbaly true. id consider some JB weld or some sort of flange sealent i addition . IM not a jb weld kind of guy but it could not hurt. there ar lots of better plastic steel type products out hereEven if knurling allows gas to escape, carried with the gas is powder residue. Just start out shooting non-corrosive ammo, this residue will hard-fill any voids caused by knurling and seal up any leak. After that, shoot any ammo you want.
my 223 vsrmint build has a custom clamp on block an must distort when its tightned up. I have a slight barrel to block leak but it hasent sealed up in 5000 rounds an may be getting worse. the port sees over 50,000 PSI so if its noit perfect it will leak at least initaly .
I have peaned one in the past. the inside of the bottom of the GB is were I applied my diviots It did work fine. the fit dosent have to be that tight any way. not like a trunion to barrel. it just need to be tight enough to seal. i have a few builds that the block almost slid on by hand were I jsut pinned ot an never had a issue. Likely if I had frose th barrel an warmed the GB it would have slid on by hand.
If there was a way to drill the slots in the barrel slightly under size so the pins were really putting a side load on the GB it might work also. I dont know how you would drill the slots under sise a little but im sure there is a way. just thinking out loud.
wonder if there is a wy to shrink the block???? im sure it couls be hard chromed or some thing expensive to add a few thou. hell likely just some duracote oor other high temp epoxy might even work . maybe not. I wonder if the gb could be heated an some how shrunk during a temperin process or of it could be evenly squezed down to size an rebored . agin just thinking out loud.
you could always knurl it an then smooth away most of it but the bottom.
hell Id just peen it an see how it fits you can always knurl it if it dont. sorry im rambeling to much coffee .