I have several AR 15s, an FAL, and an HK91. I still love my old carbine even though I don't shoot it as much as I would like. A lot of history in these old guns.
I have been using this ammo in my trapdoors.
https://www.midwayusa.com/product/605645/ultramax-cowboy-action-ammunition-45-70-government-405-grain-lead-flat-nose-box-of-20
It is low power smokeless powder. It has worked well for me. I reload the brass using 300 grain bullets with a light...