I've used their "cowboy" ammo in the old timey western boxes. No problems at all with the .38 Special. The 45-70 ammo left unburnt powder in the action of my Springfield Model 1888. I think this was because the ammo was underpowered and the case necks weren't expanding enough in the chamber. But since I specifically bought the "cowboy" ammo because it is loaded to lower pressure, I didn't complain.