We'll start with this well developed personal phenomenon the writer experienced. I have a plain old fashioned barrel with a hole pointing away from me. Even if I have a concave crown, all gas-based forces (um, pressure) are escaping in a direction
away from me. That means that fellow's "covered the shooter....spit sand for 15 minutes..." is a load of horsepucky. Unless he was shooting into a heavy wind, and that would have been equally unsmart.
The majority of muzzle breaks on hunting rifles have ports drilled at an angle directed
toward the shooter at 90 to 75 degrees from the bore. You see, in order for a break to be effective for it's original purpose (dampening recoil), the jetstream needs to pull the firearm away from you. That means the same pressure that would normally be flying away from the shooter is now directed to the side and back from the shooter, directly toward yourself (in a manner) and your friends. If this break is ported 360 degrees around it will raise dust, dirt, whatever and blast it back toward yourself and friends (I proved this myself once at the range when I first had one). The break came off and this didn't happen anymore (imagine that

)
Yes there are muzzle brakes that are designed for prone shooting, as well as dampening muzzle flip. Mag-na-port, and the big, ugly chevron shaped sucker on Barrett .50 Cals. Great, so use one.
And the BOSS and such systems where designed as a barrel weight harmonics dampener. That is why they sell a CR (non-ported) version that accomplishes the same thing. Unless of course your gunplumber/writer mentor builds lopsided brakes, with more ports on one side then the other, then I guess he could force barrels to bend to one side more than the other changing harmonics. After the bullet has left of course, as the people who get paid to research this stuff have already decided that the air forced out of the barrel ahead of the bullet has no effect on the break, but the gases behind the bullet. This means the break begins doing the work
after the bullet leaves the bore, so poo-poo on his harmonics idea.
The other one is sound. Yes breaks are louder. They have proven this already also in sound labs (managed by professionals). It also re-directs muzzle blast (same as the pressure, as that is what is causing the noise) back at you and your friends 90 to 75 degrees from the bore.
Oh, and inhale and blow the air through your mouth. Did it deafen you? No. Do the same thing through a whistle. I bet you that may have hurt. That is what happens when you force air through little holes. It gets louder. Now put 60, 000 psi through some smaller holes than the bore it is used to exiting out of. I betcha that will get louder

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Oh, and all the competition shooters the guy talked about. They use compensators on auto pistols to keep muzzle flip to a minimum so the can acquire targets at a faster rate. Like on an IPSC race gun. They don't do this to shoot itty-bitty groups, they do it to shoot .18 of a second faster on a plate set than their competitor. Go to a benchrest or F class shoot and see how many muzzle breaks you find. Very few in a winners circle.
Now don't thank me for answering as I understand, and am a little patient, if sarcastic. You see I have two little children and they ask stupid questions all the time.
Welcome to Gunnutz. One of the most important pieces of information I have learned on this sight is that I don't know everything, and neither do you. Todd Bartell does.