I looked around on the internet & saw several designs of pellet traps that would catch the pellets & keep hold of them until I was ready to clean them out. Most are all metal & noisy, but there were a few "silent" ones. But... they seem to run on stuff called duct seal that doesn't seem to exist in the UK. Plus, I didn't really fancy the designs described. So this is what I did...
Having marked the back piece I screwed the side pieces onto it, making their edges flush with the back of the back piece. Then I mounted the top & bottom pieces to make a "shoe box"
The small pieces were mounted flush with the bottom of the box, at the inside corner & flush with the outside.
Basically, I marked a line running all around the box about 8cm from the front. (Ideally this should have been 3cm) Then I used a saw to make a shallower box & a rectangluar frame.
The frame is going to make the holder for the target, hinged on one side & with a catch on the other to hold it shut. Like so.
I'm a bit paranoid about keeping the pellets in the trap - I'm going to be 5-6m away & I don't want stray pellets littering the house! First off I cut a mild steel backing plate & screwed it to the back of the trap. I also mounted a strip of spare steel plate at the bottom of the target holding area. This stops pellets escaping from the bottom of the trap & also provides a way to hold the A4 targets when you're closing the door.
Then, to provide a minimum safe, all over cover, I carpeted the steel plate! A good dose of glue holds it firm.
This would be a minimally acceptable trap as it stands, but after a while the carpet would wear out & it'd get noisy, so...
While duct seal may not be available in the UK Plumbers Mait is. Go to any DIY shop & get some of the Evostik stuff. It seem to come in 0.75 & 1.5 kg buckets. My trap has 2.25kg in it, but you may want more. The pellets from my pistol only sink in as far as the skirts, so my safety margin is there again!
Probably only one thing of significance: The shroud at the front, which catches stray bits of target, also acts as a shade for the light getting to the target. I've actually cut the top piece in half & now have a "letter box" slot in the roof of the trap, running from the target face half way forward. If I'd made the shroud less deep I'd have missed very little debris, but would have improved the lighting.
There are occasions when it would be nice to shoot a target set up horizontally. An extra 3cm width would have allowed me to put in another baffle, vertically, without intruding on the target area. If I'd done this I'd have mounted the hinge on it, which would allow the trap to be opened while on it's side. A vertical dam for the Plumber's Mait would also be needed.
Well maybe a couple of things...