There is a big difference between case head expansion and case Web expansion.

It is generaly held that .001" HEAD expansion indicates absolute max loads, however your ballistics are quite low for that action.

Chamber size has a great deal of effect on the size cases expand.

"26.0 grains of AR-2205 = 1566 & 1565" You've listed this as the maximum listed load - was that for your rifle action or for a standard Model 94 in .45 Colt?

I'm assuming it was for the M92.

I had a lot of fun shooting 300gr. cast bullets with a case full of black powder. Of course, special care must be made in cleaning cases and the barrel including the chamber. Seems to me, they were running between 800 and 900fps IIRC.