What "The Monster" does to 16 mm lead balls

I must say that this slingshot is pretty darn effective. I think I found the ideal band dimension for the 16 mm lead balls I made with the Bellsofhythe 12 shot mould.

I tested it extensively today, in butterfly of course. I leaned a wooden plank into a corner of my stone wall in the garden. The ball flew right through the plank, hit one stone corner, ricochetted and hit the other side. The pics show what it looks like now (compared to the original condition).

Note that I am using lead from car wheel weights, picked them up for free. This material is much harder than the lead used for muzzle loaders, in fact if you use it in a muzzle loader it will damage the rifling in the barrel.