5 drams being 150 per the 'new' 30 gr. chart, and 136.5gr. for 5 drams for the regulatory load.

Bob - I'd go for 145gr. to 150gr.3F MAX. just to attempt to get the barrels shooting paralel. The pressures 'should' be no greater than for the higher energy powders in use at the time the gun was regulated. On the other hand, Swiss will develope some 15% higher speeds, but at increased pressure as well, roughly 15%.

By the time you match the velocity using GOEX, you've matched the pressure as well - kind of. If room in the case, you might match the regulatory speed at lower pressures using 2f GOEX, than 3F. That may take 7 drams, just to make enough steam to regulate & it will kick harder than a lighter load of 3F.

I am surprised that 150gr. of 2f shot so far apart, as that load should have kicked as much or more than the lighter 3F load, and therefore reduced the crossing. If room, I'd go for slightly more 2f to attempt to get the barrels to uncross.