I get to review some pretty cool stuff. But the coolest thing this isn't some unobtainable custom rifle topped with a scope that costs more than your car. It is a simple little device that makes you say, "Why didn't I think of that?"
Enter JKM Pellet Conversion Cartridges. Essentially, what JKM did was take spent cartridges, ream out the primer pocket to accept a 209 primer and inserted an O-ring to keep it in place. They also indented the neck to hold a pellet. At the time of the test, they offered Pellet firing cartridges for .221 fireball, .222, .223 .22-250, .225 and .220 swift.
The process is simple: Snap in a 209 primer with thumb pressure, insert a pellet, chamber the cartridge in your gun and get to shooting. I got the .22-250 as I wanted to practice with my predator rifle indoors this winter from various field shooting positions. I expected marginal accuracy, but what I found blew my away. At 10 yards, I was able to hold all the pellets into about a nickel size group. The noise is about like an air rifle, allowing you to shoot it indoors, and you can shoot into an old phone book or pellet trap. Done a few times a week, you will be amazed at how much your field position shooting improves in one winter.
As a side note, I ran some of the pellets through a chronograph just to see how fast they were going. With ultra heavy 28-grain hunting pellets (standard .22 pellets are around 14 grains) I was getting an average of 400 FPS -- more than enough to shoot small game like rabbits and squirrels around hunting camp at close range!