Military

"Holey" bullets claimed to go faster

"Holey" bullets claimed to go ...
CompBullets are claimed to go faster than regular bullets, due to vents that have been machined into their sides
CompBullets are claimed to go faster than regular bullets, due to vents that have been machined into their sides
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CompBullets are claimed to go faster than regular bullets, due to vents that have been machined into their sides
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CompBullets are claimed to go faster than regular bullets, due to vents that have been machined into their sides
CompBullets are claimed to go faster than regular bullets, due to vents that have been machined into their sides
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CompBullets are claimed to go faster than regular bullets, due to vents that have been machined into their sides

Competition shooters like their bullets to fly as fast (and thus straight) as possible, and they try to keep recoil to a minimum. Italian ammunition-maker CompBullet produces a series of bullets of the same name, which are claimed to both go faster than normal ammo, and produce less recoil. The secret? The bullets have go-faster holes in them.

Available in several calibers, the copper alloy bullets have a main cavity in the base, with multiple "vents" machined into their sides. These reportedly serve several purposes.

First of all, when the gun is fired, the vents supposedly allow the propellant gases to go through the sides of the bullet, providing lubrication between it and the inside of the gun's barrel.

CompBullets are claimed to go faster than regular bullets, due to vents that have been machined into their sides
CompBullets are claimed to go faster than regular bullets, due to vents that have been machined into their sides

As the bullet exits the gun, the gases symmetrically shoot sideways out of the vents. This - so we're told - creates a "muzzle brake" effect. A muzzle brake is a device fitted to the end of a gun's barrel, that redirects the gases as they leave the gun, to offset the recoil effect. The vents in the CompBullets apparently serve the same purpose.

At the same time, the gases shooting out of the vents are also said to create a rocket-like effect, increasing the bullet's velocity. All of you physicists are welcome to weigh in on this one, but it's hard to say if gases exiting the sides of a bullet would really cause it to travel any faster than gases that were limited to pushing on it from behind.

Additionally, CompBullets are claimed to produce less muzzle flash and less smoke. If nothing else, all those holes probably make them lighter than regular bullets, to boot.

Source: The Firearm Blog

66 comments
Wombat56
Initially I thought this might e related to vacuum drag in artillery shells. While those big shells use a slow burning powder charge to generate a large amount of gas, I\'ve thought they may also channel air from the front of the shell to the rear. http://en.wikipedia.org/wiki/Base_bleed
Ethan Brush
Found a few more holes in this theory. First, a lighter bullet is actually a bad thing when it comes to actually shooting something because it loses energy quicker. Second, there is no way the flow of gases would be symmetrical exiting those holes as a \"muzzle brake\". Any bit of extra or less gas coming out of one of those holes would dramatically throw the bullet off of its path. And this is supposed to be a competition shooter? Third hole in the theory: with match grade ammunition and lightweight, supposedly faster, bullet there would absolutely not be enough time for the bullet to be its own muzzle break. If what they said about the reduced friction is true then a 7.62x51mm version of this would travel 2500-2750 feet per second. Way too fast, especially considering the bullet is only in the spot to do that for roughly a quarter inch. Once in the air though, there is a chance that the holes could augment the boat-tailing effect. Or it could kill it completely by making vortexes in the holes, creating drag. Still nice to see innovation in the firearms world, hope they keep it up.
Facebook User
That statement of, "At the same time, the gases shooting out of the vents are also said to create a rocketlike effect, increasing the bullet's velocity." makes absolutely no sense. The only time powder gases are pushing on the base of the bullet is when it's in the bore where we would find the holes blocked. Once the bullet exits the muzzle then a low pressure area is created at the tail of the bullet but there are no gases to create your rocketlike effect. You shouldn't need a physicist to tell you that. In free-flight, there is the possibility that the low pressure area at the base will cause the small side holes to suck away the drag producing boundary layer air as well as serve as a base bleed to further reduce drag but I'd have to see proof of that.
Matt Nirenberg
Ethan Brush please keep the following in mind: A heavier projectile has greater surface area and therefore is more likely to be affected by a crosswind (windage) which would put it off target. Remember this is NOT about killing something its about putting holes in paper therefore loss of energy due to being lighter is not a problem - paper is not that strong. Flow of gases exiting a cartridge is symmetrical providing the holes are CNC machined to be exact and providing the firearm is NOT damaged, this is a simple principle of pipe design and flow - relearn your physics, your thermodynamics and fluid mechanics. The hole in the base of the projectile is centered with the main axis of the projectile therefore the flow of gases WILL be symetrical. Since when was 2500-2750 feet per second way to fast for a projectile. 2700fps is a very common speed for centrefire ammunition. Most competition shooters aim to get as high a velocity as possible as it flattens the trajectory which in turn increases accuracy. John Simpson please understand this: Whilst in the firearm the holes in the projectile will NOT always be against the inside walls of the barrel, you forget that firearms have a thing know as rifling which is cut into the barrel so that the lands of the rifling are the only thing that touch the projectile, therefore there is space for the gases to escape in the barrel which will allow a muzzlebreak affect as the angle of the holes woulde vent the gas back towards the casing in the chamber of the firearm thus reducing the felt recoil. Overall you guys commenting on this article have NO IDEA of exactly what happens inside a firearm. Feel free to check what I\'ve written here and provide sources that contradict the well know facts of Ballistics and Firearms Design.
Bill Bennett
since you can only shoot someone legally in the state I live in that is 7 meters away that has a weapon, I will stick with the 0.41\" flying ashtrays in my gun, only 15 rounds on hand, nice looking bullet, since I only do gun for self protection, worthless for me, hmm perhaps rechamber for 9mm hollow points, 21 rounds with one in the pipe in one mag, hmm, thanks thinking about my carry weapon, and yes I carry non lethal stuff, mace, a green laser and a contact taser , hmm and a knife, just to walk the dog here in Oregon
Alexander Mawson
\"uuh those...those are speed holes\"
TogetherinParis
F = MV. Lower mass means higher velocity. These bullets are probably against the Geneva Convention.
Clint Ferreira
Is it possible the holes act like dimples on a golf ball? I recall an episode of myth busters when they covered a car I clay and there was a measurable difference in drag reduction. I don\'t know the physics, but it may work. I also remember going some cylinder porting on a high performance engine. I was told th make the ports very smooth, but not to polish them. I always wondered if this was true that a polished intake port would cause diminished performance. These were wet ports, so there could been an issue with keeping the fuel suspended and atomized too.
Abu Hmeid
Dents on the surface of the bullet like the ones on a golf ball might reduce the drag
Paul Hutchinson
I did an experiment on this at school... TogetherinParis is almost right... essentially air is less viscous than a bullet... holes mean trapped turbulent flow.. meaning bullet has less drag and goes faster... If it\'s working the same way that my crude experiment with viscous oils and plasticine.