This picture is of a 1763 shortened model 2nd land pattern Brown Bess musket. 75 caliber. I use it in Revolutionary War Re-enactments portraying a Continental Dragoon. Normally the flame isn't so big, but the previous shot had not fired and, unlike my re-enactments where we never place a solid object down the barrel, this one was rammed. So this is a double blank load, although our Re-enacting loads are generally reduced, usually around 100gr of black powder. Nothing stressful for the gun, as it is made out of modern steel.