First, a little primer about noise and rifles - There's two factors contributing to the sound or report from a firearm, there's the initial "bang" from the gunpowder, and there's the "crack" from the bullet breaking the sound barrier down range. Normal .22 high velocity ammunition that travels between 1,200 and 1,400 feet per second (FPS) breaks the sound barrier and gives you that noisy down range "crack". By using ammunition that travels under the sound barrier at roughly 1,000 feet per second (fps), you eliminate that down range "crack". This ammunition is marketed at "subsonic".
But there's a lower power .22 cartridge below subsonic. My boss clued me in on .22 CB ammunition. He explained that the .22 CB (CB stands for Conical Ball) cartridge is a .22 rimfire with little or no gunpowder that drives the bullet with nothing but the explosive charge from the cartridge primer. He explained that while you can't get the 50 to 100 yard range with standard .22 ammunition, you could zap anything in air gun range with decent accuracy, muzzle energy, and less noise than any other .22 cartridge on the market.
OK...so I'm intrigued. I wander down to the store and find several boxes made by CCI of .22 CB LR ammunition. I was pleasantly surprised to find that the cartridge was offered in Long Rifle (LR) so that I could load the rounds into my .22 magazines. The rounds look exactly like standard .22 ammunition, so keeping them separate is a must. Once I got this new ammunition home, it's was time to test!
Ruger Mark IV w/10 inch bull barrel - I assumed that the ten inch barrel would absorb enough of the sound to make this the perfect platform for the .22 CB and backyard plinking. As this was a semi-automatic, I expected that the lower charge of the .22 CB wouldn't cycle the action and I would have to cock it between shots. No big deal; I could live with that. However, I found it pretty loud; the pop was distinct and would surely turn heads. It wasn't as loud as a standard firecracker, but somewhere right below the smaller "lady-finger" firecracker. I got decent groups at 22 feet, but it's just not as quiet as I expected through the pistol.
Ruger 10/22 Target Model w/Bull Barrel - Next, I pulled out my target rifle and loaded the magazine with the .22 CB. When I released the bolt, the rounds didn't chamber as smoothly as with the pistol, but with a bit of care, I could rack the slide and chamber the rounds. It's clear that if I was in hurry, it would be problematic. I pointed the rifle at the ground and squeezed the trigger and the sound reduction was shocking. No "bang". None. The longer barrel completely absorbed the pressure and nothing escaped except the sound of the hammer dropping and the "pffffftttttt" of gas behind the bullet. This rifle is as quiet or quieter than a pellet rifle. Unbelievable. The .22 CB LR round turns your .22 rifle into a hard hitting air gun that you never have to pump!
Conclusion - If you've got a .22 rifle, the .CB LR cartridge is a *must have* ammunition option for backyard plinking and critter control. I can't stress enough how impressed I am with this round in a .22 rifle.