Thanks for the info Bob.

Just curious, what is the pressure for the 65mm 16ga? I Was under the impression that shotguns typically ran at the same pressure ranges. The 20 has a smaller base therefore less bolt thrust than the 16 but not by much.

Here is the deal.

The portion of the 20 ga tubes that are turned for sleeving is .06 thick. On the last trial, I used a 12ga chamber reamer to bore the 16ga block and turned the 20ga blanks to match.

If I simply sleeve it to the 2.5" monoblock, I will have an outside thickness of .125 which is adequate, but there is still .5 of chamber past the seam that they are joined at.

If I cut the monoblock at 3", the quick taper of the original barrels leaves me with around .100 thickness but with a .5 stub past the block.

The question is whether one is actually better than the other?

The next step is to find a proper rib. More of a raised shotgun rib than a rifle style as I plan to have it usable as either.

Thanks

Tom