While doing some home repairs this past summer I found these in one of my walls.
I'm not sure how they got there, but I recognized them as the Speer practice ammunition.
I saw them today and thought, it's ugly, cold & raining outside, why don't I clean those up and do some indoor plinking?
I cleaned them up with some soap & warm water, then dried them with a paper towel.
This is what the inside looks like:
Basically it is a short plastic case that you seat a primer in, just as you would a real brass case, then seat the plastic bullet (no powder, primer only!) and fire away.
BTW these are still available for sale (when you can find them in stock) in 38/357, 44 & 45 ACP Speer Website
I loaded them with my RCBS priming tool using large magnum primers. They seated with very little resistance
I then inserted the bullet and pushed it until it stops.
The bullets measured .345", a bit on the small side for a .357 bore. I guess that is what makes them re-usable, but will no doubt affect the accuracy.
I loaded 5 of them into my SP101, they look funny with those larger than normal primers and the red cases
I set up a backstop using 1/2 of a cardboard box and some styrafoam, thinking to myself, this should stop a plastic bullet....
Those suckers went clean through the styrafoam, the cardboard and bounced off my door. I lost 2 of the 5.....that was fun........but short lived. Time to buy a whole box of these bad boys and build me a real bullet trapping target!