All of the talk I've seen recently on PP shooting sort of got the fires lit and I've started playing with one of my .45-70 PP rifles that hasn't seen action in a while.
The rifle is a C. Sharps 1874 with Dan T.'s bore diameter PP chamber. I have two rifles with these chambers and they both shoot pretty well.
I brought one of them up to the silhouette range the other day to compare a couple of loads, and have done some short range ( 200m ) shooting.
At the ram line I shot two loads 20 rounds each, same powder charge, just different bullets and paper. One used the BACO 443530E bullet with 0.002" paper dry patched, and the other used the BACO 446535M bullet dry patched with Seth Cole 55W. Both bullets come out at basically the same weight when cast in Rotometals 16:1. The 443530E bullet needed about a minute less elevation at 500m, but seemed a touch less accurate than the 446535M. I might order the E bullet in a .446" diameter and give that a try too.
One other observation is that I stretched cases with the smaller diameter bullet using the 0.002" paper. I suspect that this was mostly due to me annealing the case necks to be a little softer than what I normally do for PP bullets. I decided to try this as it's working very well in my GG rifles. I might stop that as I don't think case stretching is much good for accuracy
In recent 300 yard testing, the 443530E bullet shot the best the rifle has ever done at that distance, and with accuracy as good as any of my Shiloh GG bullet shooters.
Another thing I've been playing with is fouling management, which I think is the real key to making this stuff work. I'm using a wiping mixture that is almost all water, with just a touch of Ballistol in it which seems to be an improvement over the 10% mix I used to use.
One of the things that I think has made these rifles shoot more consistently for me is to run my dry patched bullets through a Lee .450" push through sizer before putting them into the case.
Chris.