I don’t have a 45-70, but I do have an old 50-70. It is a Sharps Carbine chambered for the metallic cartridge and was manufactured in the mid 1800s. It fires a 500 grain bullet. I have had it over 30 years, but never fired it.
Probably better you don’t fire it. That rifle has antique value that will only increase. Why take a chance with it?
I have an 1866 Springfield in 50-70, which may have been used at the Wagon Box Fight in 1867, in which U.S. soldiers had been using 1863 muzzleloaders & the Indians would provoke a volley then charge before the muskets could be reloaded.
Came the day when the soldiers were issued with breechloaders. The chief ordered a feint charge, the initial volley was fired, only now the command was given to fire at will and a steady fire ensued, dropping braves at an appalling rate.
Took several more charges before Big Chief realized the soldiers had more bullets than he had braves. Nice piece of history to own.