I have muzzle brakes on all my heavy caliber rifles. Every
functional muzzle brake I ever used resulted in lower POI's.
In the case of Ross' brake, it adds weight to the end of the gun, possibly changing the harmonics and reduces the tendency to flip. An interesting comparison would have been to also shoot without either brake in place for a control. Real brakes divert gas. That's how they reduce the
rocket effect. If a brake does not divert gas, it will not significantly reduce recoil or flip. That having been said. Fat bore rifles with fast burning powder are probably at the bottom of the list for rifle types that benefit most from a brake. So in the case of the 450b, if it works at all, that's a strong testimony to it's effectiveness.
I'm not ripping on Bushmaster for no good reason. They make a great rifle. I just resent putting accessories on guns for the sake of
eye candy. All they had to do to that
flash hider was weld a flat washer on the end with a hole ~.010 over bore and it would have made a good brake. Folks with flash hiders have been doing that for a while to turn them into a brake.
Flash Hider:
Izzy:
Brake:
You be the judge...
The closer the size of the hole on the end to the bullet's diameter, the more effective a brake will be as it lets the bullet pass without gasses leaking around it until it's clear of the hole. Those microseconds from when it enters the hole until it clears the hole is the time when the path of least resistance for the gas is sideways. That's also why brakes with multiple constriction chambers or baffles are more effective. Each transition through a choke point diverts more gas. If like in a flash hider, there is no resistance to the gas blowing past the bullet during the time when the sideways exit is available, not much gas will go sideways. Some will, but most just continues forward with the bullet. There is a lot of good reference material on this subject available online, including hyper-speed photography showing what I just said.
Hoot