Just be careful not to damage those silhouette targets. If they are made from 1/2 " armor plate, they are fine. But if they are made from thinner metal, that is not hardened and tempered, they will bend when hit repeatedly with heavy slow balls and slugs.
If you want to have targets for your BP shooters to plink at, try using swining bang plates, rather than standing metal targets. The standing target have their own weight, PLUS the friction of the base on the stand to overcome before they are knocked aside. They take much more of a beating than does a swining bang plate. The other benefit of a swinging bang plate is that you don't have to call a halt to shooting while someone goes down range and sets the targets back up. If you hit it, you get a great " gong " sound, and the plate swings. That makes scoring hits much easier.
Now if you are wanting to shoot for a group, to see how well you can hit a target at that range, you need to do that kind of shooting some time when other members are not present, so you have the range pretty much to yourself, and won't interrupt other people's shooting to go down and examine your groups. A good spotting scope comes in handy for this kind of work. Kust give the banger a new coat of paint, and then keep track of your hits by using the scope to spot them.