I had a Benelli M4, it would run all of the Flite Control loads, including the 8 pellet 1145fps load. Will the SBS run the same? Does it run the #1 Flite Control Buck? I know it isn't apples to apples because the pressure of a 12ga round is much lower, but when you cut an AR15 barrel down, you need to enlarge the port for equal function on some barrels, depending on port size, due to reduced dwell-time. I don't know if port size is a big deal or not, here, and don't really care, as long as the SBS reliably runs the above?

I ran a few hundred rounds of full power buck through it first to break it in; it'll eat anything & everything, including the FliteControl.

Generally speaking, mine will reliably run anything over 3 dram equivalent.  Light field target loads can get down as low as 2.5 dram eq and so I try to cherry pick the slightly hotter shells.

Have you played with the #1 Flite Control Buck, and hte 8-pellet reduced recoil (1145fps) Flite Control buck? How did it like that?