...with a 22 caliber blank cartridge loaded in the handle of this rather innocuous looking device?
Well... Tie a bit of kite string around the bumper (the white bit on the end), make some big loops on the ground with the line, insert ear plugs, stand behind and well clear of the line, pull back the spring loaded plunger on the bottom and it's bye-bye-bumper...
I used it today to launch over my house (which has a 45 degree (12/12 pitch) metal roof) a belaying line so I could get up there and clean some moss off the skylights and inspect the seals.
The bumper flew about 200' in the air before the trailing line slowed it down and dropped it in the front yard. You will get the neighbor's attention as the sound of a gun-shot rings through the neighborhood... I live on some acreage out of the city limits, so no boys in blue arrived on my doorstep. Guess I will fail the GSR test at the airport security checkpoint, eh?
I am not sure I can be very accurate with this thing to carefully place antenna lifting lines, but it certainly worked a treat for my get a line over the house to anchor to the pickup truck activity.
We of course had to turn a pack of golden retrievers loose to chase an untethered bumper which was a bit of a riot on a sunny Saturday in the northwest.