The use of muzzle brakes is debatable. Some people will swear by them, while others will let rip of a swear word or two. Still, there’s no doubt that a good brake can reduce recoil up to 45%. Remarkably, the best brakes, when installed professionally, seem to have no adverse effect on accuracy.
Experimenting with Muzzle Brakes
Accuracy will suffer if the exit hole is too small. In other words, if it is 0.005 inches over the bullet diameter, then accuracy will suffer. On the other hand, accuracy will suffer if the exit hole is over 0.25 inches deep. It is the depth of the exit hole that creates a tube that the bullet must pass through on its way to the target. Should the depth of the exit hole be too small, then the metal around the hole will erode very quickly. Even though there is not all that much heat and pressure (5000 psi) present at the muzzle, it will fail if there if the metal is too thin or the hole is too small. This is the case as the air tries to pass the bullet, which upsets the flight.
The best accuracy and effectiveness of the brake was obtained with a 0.02-inch bullet diameter. No measurable reduction in recoil between 0.005 inches and 0.020 inches could be detected. In fact, a measurable change in recoil took place at 0.040 inches over the bullet diameter. The minute the exit hole went over 0.040 inches, the brake began to lose its effectiveness quite quickly.
The Role Holes Play
The most effective braking was achieved with a 1-inch diameter at the exit hole consisting of a ¾-inch exit hole on each side, which took place just in front of the muzzle. Remarkably, the bullet passes through a cone of 35 degrees before it exits the brake. This is what we call an Incredible reduction of recoil. Some would call it loud and ugly. However, it’s very nice to make use of the muzzle brake as you don’t need a spin fixture or a dividing head. With regards to the individual holes, it makes no difference to the diameter or the amount as long as they are big enough, and there are plenty of scope to bleed off all the gas that is trapped in the brake.
One guy who experimented, build brakes that consist of 1/8 inch Holes and 3/16 inch holes, and they both worked identically. He even tried drilling holes completely randomly which made it look like hell, and he did it in straight patterns and helix patterns. There was no difference with regards to the accuracy or the reduction. Now he uses a left to right Helix consisting of 3/16 inch holes that are 0.010 inches apart at a 2-degree offset. The brake itself ends at 2 ¾-inches with a ½-inch half thread depth to accommodate an overall extension of the barrel of 2 ¼ inches.
Funny enough, the Helix keeps the brake tight, and it doesn’t need to be indexed at any stage. This will line up with a barrel if the brake gets indexed. However, after it’s been removed a few times, the holes will shift a few degrees which will look less professional.
When aluminum is used for the brakes you will experience no difference at all. Somehow, the aluminum hardens after repeated firing.
What happens when holes are made on top?
In doing some tests, not having holes all around the brakes would affect the accuracy quite a bit. In some ways, it does something to the bullet as the air gets pushed ahead of the bullet thereby creating and unequal turbulence in the bullet box. Our guy did some tests and tried drilling a few holes in the brakes only on the top and from there he completed a few holes at the bottom as well and every time the accuracy improved.
Why Muzzle Brakes Work Best When You Use High-Pressure Cartridges
In a lot of ways, the higher the pressure of a particular round is, the more effective the brake. The 220 Swift, which is considered the king of reduction, was used to check the accuracy of this theory. Fitted with a decent brake, the Swift only moved a ½ inch to the rear and resulted in a zero muzzle rise.