Originally Posted by
Rich
We made our boxes out of ply and chipboard and lined the inside with steel sheet. 3mm was hammered by the pellets into a hollow shape and the corners lifted. Now we use a 5mm plate fixed to a thick timber substrate but spaced off the timber by a few mm using rubber grommets.
Initially we made the mistake of angling the striker plate at 45 degrees, thinking the pellet would bounce downwards. But because the pellets distort they don't behave that way, and the spent pellets tended to slide down the plate and smash holes in the base of the box at the back. We found that an angle of 70 to 80 degrees works much better.