Afternoon shooters,
Shouldn't be hard to built. Check out the plans listed on the first reply - I haven't - and I expect theuy will guide you through.
I made one out of 1/3" diamond plate years back and used it in the basement.
The city fathers are probably still flopp'n around in their graves as this is a LIBRAL!!!!! collage town we are talking about.
I used the plate for the top/bottom with about 1/8" or less for the sides.
Took a piece of about 4" steel pipe and cut a slit down the side, wide enough for the diamond plate to extend into the pipe.
I allowed the upper plate to extend farther into the pipe then the lower, probably by an inch or so.
This trap proved to be quite clean.
A leg of some sort needs to be welded to the bottom of the pipe to keep the opening of the trap in the correct angle/position to the shooter.
If this trap had a fault, it was the fact the lead was a bit hard to empty from the pipe. Shouldn't be much of a problem to cure.
Remember, the bullet will glance off the metal plate at about the same angle it strikes.
I do not recall the angle I used for the top and bottom plate, but expect it was something less then 90 degrees.
Not an over whelming project, so build, use and enjoy!!
Keep em coming!