Have authorization from ATF to make up a single shot or bolt action rifle in .58 U S Musket. I plan to use smokeless powder to achieve velocity of around 950-1000 ft/sec, the same as 1861 Springfield Civil War era. Bullets were 500-530 gr minies. I need a barrel with correct bore and OK with smokeless. Not sure what action I will use-- possibly T/C. Who makes over-50 cal barrels for smokeless powder? There are two different case lengths-- a 1.2" and one that is slightly longer-- 1.4 or 1.5" Rim is about .72 and base about .60. This ctg began life as a rimfire and is now available in boxer priming. Springfield converted some 1861 & 63s to the .58 Musket, but soon replaced it with rifles in .50/70. So, the .58 U S Musket ctg had a very brief lifespan.