I found this description of the modifications done to the "Fremont" Halls. I can't figure out how a .530(groove depth?) ball sitting in a .590 chamber could center itself to enter the .52 cal bore? For that matter, even in a .564 chamber. Does anybody know how this worked? Was it intended to shoot a .58 minie out of a .52 bore? I know some sources say that the bore was freshed out to .58 but apparently that's not the case.

Thanks,

Duane


With the opening of the American Civil War, the US Government quickly came to the realization that this was going to be a longer war than originally anticipated, and more small arms were going to be needed than originally thought. Seeing the opportunity to make a quick dollar, numerous arms dealers and speculators jumped into this market and procured arms (from whatever sources were available) to resell them to the US Government, and in some cases to the various state governments as well. In June of 1861, Arthur Eastman of Manchester, NH offered for sale 5,000 altered Hall M-1843 Carbines. He proposed to have their .52 caliber bores rifled with 6 grooves, and to have their chambers enlarged to accept .58 ammunition. The barrels of the guns were not enlarged to .58 caliber (as the description of these carbines in Flayderman’s leads one to believe), only the chamber of the breechblock was enlarged, from a nominal .564 to a nominal .590. The theory was that the larger chamber feeding into a substantially smaller barrel would help reduce the gas leak problem that had hampered the Hall design since the very beginning of production.