I use Trail Boss in everything I shoot from .38spl thru 45 Long Colt and 45 ACP, including 45/70 Gov't. Great powder. Because of its shape you can not double charge a 38 or 45LC case. It overflows.trail boss rocks! You can use it in just about any rifle round and pistol. Doesn't work in 9mm, but just about anything larger it works fine!