We have to have pellet traps for our range too, we are next to a creek, and there is concern about rain run off carrying lead fragments into the creek.
So, we made 18" square boxes with a metal slanted backstop that forces the pellets down into a sand base. Hanging in front of that backstop is different size swingers for different distances... 1/2" to 4" placed 15 yards to 100 yards.
With 1/8" steel backstop and 1/4" steel round disks for the swingers. These can handle around 120fpe without damage. If you want them to handle higher fpe, then you can fill in behind the steel backstop with some concrete poured in.. very solid now.. probably handle 300+fpe.
What's nice about this set up is you can see your misses if you paint the backstop white and the kill paddle red or yellow.
No strings, targets don't fall, but the scoring person watches to see if the paddle swings or not. This is for our Extreme Field Target, but you can choose any size for the distances you plan on shooting.
Wayne
