

I loaded up 19 rounds using 24 grains of 5744 and a single sheet of 1-ply toilet paper under a 405 grain plain base cast bullet, sized to .458. I wasn't too optimistic about the accuracy since reading Mike Venturino's Shooting Buffalo Guns of the Old West. He said that it is common for the trapdoors to have oversize bores. I haven't slugged this one yet. He also mentioned that the 405 grain cast bullets were not all that great for accuracy in his gun, but the 520 grain bullets shot great. I'm ordering a 520 grain mould for this rifle.
Well it was off to the range. I set a target up at 50 yards to adjust the sights. Talk about shooting high! I stuck a second, smaller target on the bottom of the paper and adjusted the windage. Now I was ready for 100 yards. I shot the first 5 rounds .... high and a little to the left. I adjusted the windage and aimed lower for the next 5-shot group. The dadgummed rifle shoots 14" high at 100 yards, and I have the rear sights down as low as she'll go! Looks like I'm going to have to install a higher front sight. I don't know what the 1800's US army was thinking when it came to close-combat (i.e., closer than 150 yards). Maybe you aimed for the fellow's crotch. Anyway, here's the more on-center, second 5-shot group ....

The five-shot group was 4 & 5/16" at 100 yards. The bore had no leading, so far as lead deposites go, but there was a thin, grey lead wash on the walls of the bore. This tells me my .458 bullets are probably a bit undersize for the groove diameter.
Chrono results for 24 grains 5744, 1 sheet 1-ply TP & 405 FP, PB bullet: 1,278 fps, E.S. = 53 fps, S.D. = 16 fps.
I figure that black powder will bump up this soft cast, plain base bullet a bit better, so that's my next project. The 500 grain bullet mould could take a month or so.
For my final 5 rounds, I figured I'd try some offhand shooting. I have to say that the boys back in the 1800's must have had one strong trigger finger. I practically had to throw a rope around the trigger and hitch the other end to the pick-up truck just to pull the trigger. That's a bit of an exaggeration, but that durn-tootin' trigger and that massive hammer time makes for some interesting offhand shooting. I decided I will not post a photo of the results. There is a limit to how much a fellow should humiliate himself on the web, and that target was past the limit. All I'll say is that at least all five shots were on the paper, and that was about it. Obviously, I'm going to need a bit more offhand practice with this old girl.