Re: shooting movers
Water balloon holding top of tire, kill it, tire rolls down an out of the angled frame. Use 12" tires, if you can find them if not then 13",... bigger than those, your fooling your self.
Many ways to skin a cat,... 1 moa dinger with auto latch works also. Big piece of cardboard, between you an side kick, you at ready, your side kick shoots the trip when he/she wants,...you have to be "shooter up" longer than normal to add reality.