Presumably, you've picked up Speer plastic cases and bullets.
This makes fine practice ammo for short-range. Of course, it's not intended to be used for defense.
Primer residue builds up quickly in the barrel. Keep a cleaning rod with bronze bore brush handy. About every dozen rounds or so, run the brush up and down the barrel to remove the primer crud.
There is no need for solvent; just use the brush dry.
A cardboard box filled with wadded newspaper will stop the plastic bullets. Kind of a pain to find them in the wadded paper, though.
Years ago I used a box about 2-1/2 X 2-1/2 feet. The base faced me, onto which I pinned a target.
Inside the box were carpet scraps, hung from dowels that pierced the top of the box. The bottom of the box (normally, one of its sides) was removed and scraps of heavy cardboard were used, with duct tape, to create a funnel-shaped floor.
Under this funnel I put a shoebox.
It was great!
With each shot, the plastic bullet entered the box, hit the carpet, lost all energy, then fell down. It ran down the sloped side of the floor and plopped into the shoebox.
After a box or two off shooting, I pulled out the box and there were all my plastic bullets. No searching through crumpled newspaper.
Yes, you can reuse the bullets. I was shooting a Ruger Blackhawk .45 Long Colt and loading plastic bullets in brass cases. Some bullets were used up to a dozen or 15 times before they got so beat-up they were unusable.
When I went into the Air Force, my parents threw away that target box and I never rebuilt one.
But it's a good design.
One more thing ... NEVER
have real ammo anywhere near your shooting bench. Keep it in another room, well away from your plastic ammo when you're shooting. This will keep you from shooting a hole in the wall, and possibly hurting someone in the bullet's path.
I knew a guy in Denver years ago who practiced in his garage, against a box filled with newspaper. Why he kept live ammo beside the plastic ammo is anyone's guess.
One day, of course, he put a .38-caliber hole in the back of his garage. It crossed the alley, went through another garage, and put a hole in the passenger door of a Buick parked inside.
His neighbor, remarkably enough, didn't press charges. Nor was he sued. But he dismantled his garage range and moved it to his downstairs, where an errant bullet would meet a concrete wall and yards of soil beyond that.
Can't be too careful, ya know.