So, I still have several plow disks laying around, and needed another project. How about a gong to be rung at 500 yards with a rifle! Should be a hoot, and very simple to build.
Started with the frame. Cut my pieces of 1/2 inch black pipe to the length I wanted, then welded pipe fittings onto the ends in order to make a frame. Basically, I did both ends at a time. I set one on the floor at each end of the pipe, then laid the pipe on top of them and tack welded them. By doing so, it gave me a pretty good assurance that both ends were parallel. So, I completed one set before doing the off-set set.
The offset angle is just whatever happened when I laid the pipe on the second set of pipe fittings and let the first set rest on the ground. No real science to this.
Closed up the hole on the front of the disk with a piece of scrap 1/4 inch steel plate.
Finally, welded bolts to the back side of the disk, then pushed them through holes I drilled into a piece of belting material folded in half (Very very tough stuff). So, it gave me a nice loop at the top for hanging on the frame.
Now to learn my bullet trajectory chart well enough to start hitting it! It should provide a nice clang as a confirmation of impact.