I picked up a 54 cal Hawken, thinking it had a 1:48 twist barrel. I also purchased a RCBS North-South Skirmish minnie mold, (adjustable weight) because I would rather use the conicals because they are a bit heavier for hunting Elk. (that, is the background)
I started off using 70 grains of FFF, with a PRB, and @ 100 yds, all was good.. used the minnie, and it was all over the place. Not even on the paper. I did see where one of the minnies hit the target support board,.. sideways.. left a nice profile in the board. I checked the twist rate and found the barrel was a 1:66..
So, I started looking at spin rate for stabilization, and ended up increasing the charge to 95 grains, which gave me nice paper punch type holes @ 50 yards.. accuracy is still not as good as PRB.
Fouronesix gave me this advice on the Lets Talk About Twist thread:
"That gun should shoot the minie you have but the 95 gr FFF seems way too hot. Near pure lead and about a 50-55 gr load of BP should work. Another thing overlooked by bare conical/minie shooters is the potential for leading in the bore. Make sure there is no leading in the bore.
If it shoots PRB accurately then the barrel/bore should be good. I've noticed the definition of accuracy by different shooters is different. That rifle should be able to shoot PRB into 1-1 1/2" at 50 yards from a good rest, good sights and good technique with the right load. If it does that then the barrel/bore is good. If you are using battlefield techniques and methods with the minie it may not shoot no matter the load. Those old "conventional wisdom" methods called for a minie that was quite a bit smaller than bore diameter--- using the undersized minie for ease and speed of loading a badly fouled bore on the battlefield-- accuracy was not the priority. I've found over and over and over! that if the minie is of good design and cast without voids of near pure lead and is sized no smaller than bore diameter it will shoot well in the 54 and 58 calls with twists ranging from 1:48 to 1:78+. It may require cleaning/swabbing more often, but when the outcome calls for accuracy not speed loading, that is what usually works. "
The minnie cast, is from near pure lead, measure .540, and provide slight resistance on a clean bore when loading. With 95 grains, the first shot, goes somewhere.. doesn't hit paper @ 50 yards, subsequent shots, are on paper, and cut nice clean paper punch type holes, no tearing.. PRB, with the same 95 grains, gives very good accuracy, @ 50 yds.
So, I will be trying the 50 -55 grain load, and will report back. I do appreciate the advice of the more seasoned black powder shooters here.