Not really looked into this type of shooting indepth yet.

Quick suggestion, if you can't make a turning device, use a board that is taller than you to stand behind the firing line. Break cover aim & shoot, then go back behind board. If possible set targets at different positions. Or have one target & a assistant to reposition target. So when you break cover you need to find the target then fire. Different timings could be set.

Regards
Paddy.