My mistake. I did not mean bullet lube.
I bought 45=70 .459 from laser-cast.
I measured the barrel out at .449. That probably won't help accuracy but will it harm the barrel ?
I don't know the alloy.
I have had the trailboss for about 3 years. I haven't loaded since I haven't been to SASS since I am working weekends. I have since found out the Trailboss is impossible to find. I may switch powers for my next batch .
I now realize that there is a small dock on the back of the breech block that seems to be there to cover the linkage for the lever and the disk falls out of place and jams. Is that disk really necessary?
It sounds like you measured the bore diameter. Bullets are sized to be very slightly larger diameter than the groove diameter. Your bullets are probably close to perfect for your barrel, which will be about .458" groove diameter. Commercial bullets are often overly hard for the older cartridges. That'll probably be the only drawback to worry about. Trying to load down to keep recoil tolerable combined with harder cast bullets often hurts accuracy and encourages leading. If the rifle seems not very accurate with your first loads, look around for softer bullets.
TrailBoss is going to work ok, 3 years old or not. There are quite a few new powders that do well in 45-70s. One modern one that is made for the old cartridges is A5744. It's very good at giving uniform velocities and is as economical as any. Most powders are going to meter far more uniformly than TB, and are sold in pound cans that have more than 9oz in them.
Sorry, I don't have a '74 Sharps so don't know what the disk that's jamming your action is, but for sure there shouldn't be anything that can do that in a falling block action simply because it's dry of lube.