Many moons ago I did wax bullets in modern cartridge guns. Amoung the things we did with them was build a large simple bullet trap using multiple layers of card board on either sid of a one by one set of seven foot long rails backed by a free hanging blanket. The ladies I shared the house with would do their home invader drills with their little .38 SPL revolvers, flashlights and phones and actually engage a man shaped target with the wax bullets.
More than a few rounds appeice though and it got stinky in the house and folks started to worry about lead from the primers.
Any how at the time I was doing some action style shooting with a 1911 style .45ACP and so modified som cases and single loaded the same to practice presenting and firing from the holster. I was encouraged to "take it outside." I on a few occassions during the middle of the day went out and did so, and even got to do some flashlight work around ninish one night. Then one day I was out just before sundown and the neighbors were home from work. While they said nothing to me about it they said to the 911 dispatcher that someone was shooting at a house (I was using the blank section of block wall between the bathroom and kitchen as a final back stop) with an automatic pistol. Officer friendly fortunately had the forethought to go to the front door first and the girls explained what I was doing and how and then offered to go have me lock and clear so Officer Friendly could comfortably approach me for a discussion.
Naturally I do not argue with Officer Friendly "in the field" (that is what courts are for) so all was settled happily with my promising not to frighten the neighbors and "take it inside"
I was fortunate to have an understanding Officer Friendly take the call and shudder to think what might have happened if Officer Jack-Booted Thug had made a dynamic entry into my back yard while I had .45 ACP in hand.......
Something to think about "legal" or not.
-kBob