I was recently drilling out a .22LR barrel to use to test .25 nail gun blanks (they are the same diameter as .22 mag). Before I drilled the barrel though, I took a lead ingot and drilled it out with the drill bit that I thought would be the best fit just to see how tight / sloppy the blank would fit in the hole.
This kind of got me to thinking though... I wondered what would happen if you too a large caliber bullet and drilled a hole in it just large enough for the .22 or .25 nail gun blank and then set it in there with a drop of glue to keep it from falling out during handling. I'm sure it would work if you shot a metal target, but other than perhaps providing a flash to see where you hit, I don't think it would serve much purpose since the bullet is going to splatter anyway. But what about on "soft" targets? Would hitting ballistic gel still cause it to fire and if so, I have to wonder what the wound channel would look like. I'm thinking it would be a bit more shallow and perhaps with a few fragments going wherever.
Anyone ever tried this?