The projectile is a heeled wadcutter style bullet made of a hard black plastic weighing approximately 14.8 grains. It is about a tenth the weight of a similarly shaped lead wadcutter bullet. This plastic bullet is designed to snap into a Speer red plastic cartridge case which has a primer pocket that is sized to accept a large pistol primer.
Powered only by a large pistol primer, both the cases and the bullets may be reused multiple times provided that you have a backstop that can catch the bullets without damaging them, something like a piece of carpet.
The bullet diameter is somewhat undersize for the bore, being only about 0.345 inches in diameter. When fired in a revolver, the bullet rides on the lands and is not appreciably engraved by the rifling.
An article from the July 1965 issue of the American Rifleman suggests that a group size of less than 1 1/2 inches at 20 feet can be expected with plastic bullets. (Olson, 34)
In the Consumer Reports article mentioned above, the Consumer Union reports that accuracy was seriously reduced after the bullets had been used more than ten times(282).
I tested the Speer plastic bullets and cases using two revolvers; a Rossi M88 in 38 Special with 3 inch barrel and a Taurus M66 in 357 Magnum with a 6 inch barrel. I have fired both revolvers extensively with standard 38 Special ammunition and both will shoot within a few inches at 25 yards when fired from the bench.
Before testing, the cylinders and bore of both revolvers were carefully cleaned of any powder residue, lead fouling or oil.
Thirty cartridges were primed with CCI 350 large pistol magnum pPrimers as per the instructions on the back of the Speer box.
Ten rounds were fired from each revolver over a chronograph to a target 25 yards distant.
Fired from the Rossi M88 38 Special revolver, the average muzzle velocity generated by the plastic rounds was 311 feet per second with a standard deviation of 17.3 feet per second.
The average muzzle velocity produced when this ammunition was fired from the longer barrelled 357 Magnum Taurus revolver was 306 feet per second with a standard deviation of 39.8 feet per second.
If the plastic bullets had been able to penetrate the cardboard backer of the target frame rather than just bouncing off, then I belive that the group size produced by either gun would have been measured in feet not inches. To make a fair test of accuracy, I did fire 5 rounds from each gun into a pellet trap at 15 feet. The group size produced by each revolver was about 5 inches. One errant shot did embed itself part way into a closed cell foam archery target that I had set up as a precautionary back stop, which clearly demonstrated that at close range these cartridges do have the potential to cause injury to either people or drywall.
It found this product's performance to be rather dissapointing and I am probably not the only one who feels that way. I know many people who have tried Speer plastic bullets, but I don't know anyone who still uses them. They might has some entertainment value for close range point shooting drills or denting empty soda cans in your garage on a rainy day.
As for my self, when I consider the cost of pistol primers today, the Speer plastic bullets seem hardly worth using.
For this sort of short range shooting, wax bullets would seem to be a cheaper and more accurate alternative.
CU (Consumers Union of U.S.) "PRACTICE BULLETS" Consumer Reports Buying Guide Issue Vol. 30 1965 p. 281-282
Olson, Ludwig "Shooting Plastic Bullets" American Rifleman July 1965 p. 34
Speer Inc. "Speer Manual For Reloading Ammunition #8" Speer Incorporated 1970 p.15