I've done a little bit of BP cartridge silhouette shooting and it was a hoot!!!
The smokeless guys that were spotting would say that they didn't see the shot thinking that we were way off then CLANK and over it would go. Our slugs were going half as fast as the high power and they would look away before the bullet got there. (only got 5 or 6 out of 40 but not bad for iron sights out to 500m)