The CompBullet is an interesting bullet made by an Italian company. The bullets, made from a solid copper alloy, have vents machined into them. According to the company, these vents reduce friction by allowing gas to lubricate the bullet as it passes through the barrel and then act as a muzzle brake as the bullet exits the barrel. They apparently also reduce smoke, increase velocity (a rocket effect as they leave the barrel) and reduce muzzle flash. In other words, they are miracle bullets.
The use of gas to lubricate firearms is not new. Many automatic firearms have fluted chambers to vent gas through the chamber and around the brass case to lubricate it during extraction. This could work for bullets as well, but would it help enough to make significant improvement in ballistics in a pistol length firearm?
As for the muzzle brake and “rocket” effect claim, the physics is beyond me. I cannot work out how gas venting out of the bullet for a brief moment in time would have any effect on recoil. Surely because the bullet is not fixed to the gun any muzzle brake effect would slow down the bullet not the recoil of the gun?
As for the claim that it reduces muzzle flash and smoke, again I don’t understand how it would make any difference. The company has photos on their website purporting to show decreased flash and smoke using the CompBullet compared to regular FMJ bullets. A single photo is meaningless, an ultra-highspeed video would be needed to make an accurate comparison.
That said, I would still like to try using one of these bullets. The company makes them in a variety of calibers and weights for pistols and .30 125gr rifle bullets.