Jim:
I do not know what experiance you have in shooting a "Replica" .58 cal WBTS Rifle Musket. They can be accurate WITH the proper load, not always the exact load they used back then.
I wrote this out a while back for a friend, and want to pass it onto you, and anyone else interested...
You have to remember that the Muskets in the WBTS were Progressively Depth rifled. The Groove diameter at the Breech end was about .015" deep, going to .005" deep down at the muzzle. A heavy Minnie ball would expand into the deep groove when the powder went off. Then it has a good "bite" on the rifling as it moved down the bore. As it moves down the bore, it gets squeezed down in the groove area and stops any "gas cutting" that destroys accuracy.
The bore diameter is the same all the way through the barrel.
On the replicas, the groove diameter is the same all the way through! (Just as the bore) A heavy Minnie may travel some distance before the skirt expands into the rifling. A lot of gas cutting is going on around the bullet before it expands, and the gasses blowing by the bullet are playing havoc with the shape and diameter. (acting like a blow torch) That is gas cutting.
The bullet needs to be real close to your bore size so that skirt expansion can take place before gas cutting comes in. The bullet needs to be 1-2 thousandths UNDER bore size to fit properly
Several bullets I’ve tied have been too small for most replicas I have fired them in. So they didn’t work for me too well.
Most of the Bullets that Lyman makes are too small (.575”) in diameter to properly fit the .579”-.581” bores of the ArmiSport Replicas being produced. Euroarms bores are a bit smaller, but still don’t always work out with the .575” size bullets. Don’t count on the Hollow “skirt” to make up for the smaller size of the Bullet!
I use a bullet that was designed by the late Tony Bagdon. His bullet is designed to shoot accurately in the non-progressive depth bores of modern replicas. This bullet casts out at .580” diameter, and I can size it down to .577” to fit my Euroarms Enfield, or use as dropped from the mold for the .581” bore of my ArmiSport 61 Springfield. This bullet is a 405gr Semi-Wadcutter design that has a thin skirt, for use with lighter loads. It is marketed under the name of Hodgdon, the re-loading components Company that helped Tony design the bullet.
The Hodgdon bullets were designed to "Obturate" (expand) quickly when the powder went off and also hold a large amount of lube to keep the fowling soft so you can load a close fitting bullet without it hanging up in a dirty barrel. The lube can act somewhat like fluid “gasket”, helping to seal up the bore around the bullet as it travels.
FFFg powder goes off "harder" than FFg powder , thereby helping to expand the skirt of the bullet fast and get a bite on the shallow grooves of the bore! Using less powder means less fowling after each shot also.
The Hodgdon bullet has shot more accurately than any other bullet I have tried! I have taken 2 other rifles that wouldn’t hit the broad side of a barn with regular Minies, and come out with 5-shot, 50yd groups that were 1-3/8” c-to-c. If you weigh, and group your bullets to equal weight, and use a consistant "LOT" of powder, not switching cans/lots, you can get great accuracy results.
I also have a Rapine Bullet Mold that casts a .580” 470gr Minie bullet that seems to work ok with the standard load of 60gr FFg powder. But it won’t print as tight of a group on paper as my Hodgdon bullet. But it emulates the standard Military load of the time.
That Hodgdon Bullet design accounted for 2 Deer last fall! I loaned my 61 Springfield to me Brother-in-Law, so he could go Deer hunting, and he got a Buck, and a Doe. Those bullets went clean thru those deer, at a distance of 45-50yds. He was using my standard load of 38.3gr of Elephant brand FFFg powder, and a velocity of about 950fps. A very ACCURATE load!
There is much more to be said about live-firing replica Rifled Muskets, but this is the basic info needed to know what your dealing with.
Kevin Dally