1861 Springfield Project

This rifled musket bore was so corroded, I could only get a .577 diameter Minié ball about 5" into the bore. After many attempts to remove and neutralize the rust, I finally ran a 6-bar reamer set at .577" diameter through the bore to the breech plug threads. It's ugly and there is no rifling the last 8" at the muzzle. I have yet to get the nipple removed, I ran a 1/32" drill through it. The nipple is so eroded that it's hard to get a musket cap to stay in place. My 1st attempt to shoot it was a FTF. I pulled the bolster screw, worked a 1\16" drill bit around in there and dropped in a pinch of powder. Then I got a hangfire. I cleaned the bolster with a pipe cleaner, reloaded with the musket tipped to trickle powder into the bolster and it fired as it should. The following shot was also good but I can't say it hit where I aimed. It has about a 12 Lb. pull.
So, anyway, I took it out today and put 7 shots through it. I'm no marksman but I should have been able to put them on a 1 1/2 by 2 Ft. box at 50 Yards. I followed up with 3 rounds out of my Model 92 .357 Magnum and they all hit decently close to center. One Minié ball Keyholed 4" from center.
I have a new barrel in production at Whitacre's Machine Shop. I wish I could find someone who could reline this barrel to the original specs. I could have it re-bored to .600 or .620 but nobody makes a casting mold that size for Minié balls