The Op isn't interested in the backstop or variations thereof.
His Q is how do forum members pick up the bouncers from the grass......these happen when you hit a metal target so the spent pellet doesnt hit the rear of the catcher.
In reality this will be a bugga. I wouldnt bother personally.
If its an issue, prevention is better than cure so get a tarp you can roll out when shooting like an apron and then roll it up at the end hopefully catching the stray spent pellets that do bounce out
If you want to collect spent lead from the grass then that seems like a proper drag. Good luck
In a battle of wits I refuse to engage with an unarmed person.
To one shot one kill, you need to seek the S. Kill only comes from Skill