CC, I'm impressed. When I played around with very low velocity loads in the .45/70 my problem was consistency. One load would drive the bullet fast enough to make a fence post shudder at 25 yards but the next would fall to the ground a dozen feet from the muzzle and badly foul the bore.
I don't recall what powder I used, it was a very long time ago, long before chronographs were affordable. Come to think of it, I think I do recall, but if that was the powder I chose, it was a poor choice for the application, and would explain the inconsistency. I thought as long as I had a good crimp on the bullet that it should produce consistent results, but this proved incorrect. I concluded that I would have to shorten the case before the consistency would improve. I've never liked the idea of fillers between the powder charge and the bullet, so I never experimented with any. Unfortunately I didn't peruse the matter, as in those days I was of the "more is better" mind set, rather considering that less might be more.
I'm curious to know, did you increased the size of your flash holes to improve ignition in the big case? A cast bullet should be less likely to stick in the bore than a jacketed slug, but you should consider the possibility, as a longish bullet is more prone to sticking than a shorter one. However, a long bullet with a long bearing surface will produce better accuracy at low velocity because it centers in the bore better than a bullet of equal length with a short bearing surface.
Some time back, when we were having a discussion concerning sub-sonic loads, Suputin sent me a pic of a rifle muzzle with the nose of a bullet protruding from it, and underlined the importance of lube on jacketed bullets when loaded to sub-sonic velocity. Naturally, the nonexistent report from these loads means that one must be vigilant in insuring he has a clear bore before firing a subsequent round. I loaded some very slow .45 auto rounds so I could shoot in the basement when I lived down south. Actually, the soft swaged bullets were primer driven, and would exit the barrel provided they were lubed but if I reused the same bullet, after a couple of firings without re-lubing, it would stick, and that was with only a 5" barrel. Accuracy was good enough for across the basement, and penetration was similar to a wax or rubber bullet, so I went back to wax bullets to avoid "sticks."
