Well sir, like Prof said blanks are provided by the organizers at events, and they are only .45 for pistols, no .44 pistols in sanctioned events that I know of. But if you are just wanting to practice, then it is easy to make blanks in any caliber. Main thing is to drill out the primer hole. I think 3/16" but try to verify that. It helps keep the primer from backing out with the zero-recoil loads and tying up the gun. Don't use that brass for regular ammo. Fill it at least half full of any granulation of BP, amount not critical. cover with a plug of green florist foam (the squishy kind, not the styrofoamy kind) and compress it. CMSA pistol blanks don't have a wad over the powder because they are star-crimped (pretty wasteful of brass, just one use). They do have some sort of 3-in-1 or 5-in-1 or whatever blanks they provide for the rifles, since those can be .44 or .45. Might want to get your horse accustomed to gunfire if not already before firing full power loads on it.