I didn't say it wouldn't be accurate. It would probably round out in flight.
What i'm thinking is if a really tight load is squashing the ball into an oblong shape. Why wouldn't a bit looser load that doesn't squash the ball be as accurate? As long as it's tight enough to fill the grooves.
The elongated balls were now bullets and shot just fine in the 48" twist. they didn't round out, they were already round in shape, but elongated is all. Same thing happened in that .36 Sharon barrel I had that I used .375" balls in. I tried .350's and .360's but the .375's (all with a .022" denim patch) were more accurate.
I had to use the larger .457" ball in this .45 Bauska - I thought, due to the depth of the rifling at .028". That made it .504" groove to groove. This was the dark ages of education - the .70's, where I was learning the accuracy of these guns when bore and groove filling loads were used, along with appropriate powder charges. I learned that with tight loads that stood up to the pressures and speeds of heavier loads, that those heavier loads were more accurate than lighter loads with looser combinations. I learned that those loose combinations shot best with very weak loads because any more powder would destroy the patch completely. I read and re-read Ned Robert's cap-lock book, finally comprehending what was needed to shoot hard and accurately and NOT have to wipe the bore during a day's shooting.
As to my .50 Getz bl, with the narrow deep rounded rifling and wider lands, I use the .495" ball and a .022" patch. It doesn't quite go to the bottom of the grooves, but is snug enough to not allow fouling buildup, so no wiping while shooting and loading never gets hard.
I/we use tight loads so we never have to wipe the bore while we're shooting because the bore literally gets wiped, every time we shove a patched ball down.
