The original NARPA design for a pellet trap is excellent and easy to make and includes a strip light to illuminate the target.
I still have one that I made in 1976 and it is still going strong and does the job perfectly.
I made another four when we started RMTC and they have only just given way to our new electronic target changers, but until then they were inconstant use and have withstood some considerable battering!
We still use them for 6 yard MPL shooting - there is nothing better !
You can probably find the plans online, but if not I have a set I can copy for you.
Buying a stamped metal one is easier and maybe even cheaper!
Bob
Rossendale Target Shooting Club. Every Tuesday and Thursday evening 7 - 10pm.