AR guy - brakes that reduce upward motion are compensators. The concept behind them is that the gasses following the bullet leaving the barrel are re-directed upwards and that compensates the physical upward motion of the barrel by pushing it back downwards. Elementary physics.
Flash hiders are specific in that those same gasses are vented in multiple directions to reduce the muzzle flash from those burning gasses leaving the barrel.
Both devices are brakes because they redirect the gasses and that does have an effect on the velocity for the bullet that leaves the barrel. With the degree of velocity change comes a degree of less recoil. With me so far?
So, I can see the reason for a compensator on a fully automatic AR or any fully automatic rifle - help keep the barrel down and on target. The actual physics that cause the barrel to rise is the the spin on the bullet (i.e. the twist rate) - change the rifling to the other direction and the barrel would go down not up. I think that the concept of rifling a barrel must have been invented in the northern hemisphere by right handed people.
Flash hiders are useful in that when you fire at an enemy in the dark, they don't see the muzzle flash to shoot back at you - that is the concept.
Granted, both devices do 'look cool' but they have very different functions.
Everything you said was great but this... I'm not so sure about. I believe there are a few guns out there that have rifling in the opposite direction. Just has to do with the manufacturer's method of machining the barrel.
As for muzzle rise, that's because the barrel is on a different plane than the grip and stock/ forearm. The leverage of it pushing back, and then rising because of the grip/weight being underneath. Since an AR has the barrel inline with the stock, recoil mostly goes straight back. A more traditional rifle with the stock having a bend and comb in it gives it a rotating force on the grip part, making the muzzle rise
Spot on Alb.
Will, your very own .303 brit enfield has left hand pitch rifling, so do 1911 .45s.
All of them flip muzzle up. because its simply the path of least resistance. The recoil force of the bullet being accelerated generally pushes straight back against the muzzle as the bullet exits. The shape of the stock and its relative position to the bore effect how the shooter perceives recoil forces.
Muzzle brakes work by catching the expelled gasses and acting as a stop for them which, since the brake is attached to the rifle and the gasses are moving away from the rifle, when they hit the brake the energy of the gasses moving away is transferred at precisely the same moment the recoil forces are shoving the rifle toward the shooter and they cancel each other out. This is why higher pressure rounds generally get more out of the same brake as a lower pressure round. Take a .45/70 firing a 300 gr bullet at 2000 fps. the recoil generated is unpleasant even from a brake because the expelled gasses aren't sufficient enough to drastically reduce the recoil force. take the same style brake and put it on a .338 lapua that propels a 300 gr bullet at 2800 fps. recoil is much more manageable because the higher pressure gasses cancel out much more of the recoil force when they hit the brake.
Compensators work by propelling expelled gasses in a specific direction to counter muzzle flip, which again, all guns have. They are best noticed thru rapid fire or full auto fire, as its easier to keep the gun on target.
