As a relative newb to AR10's/variants, until now I had no experience with brakes. Once I started digging into them, it became pretty apparent that GOOD muzzle brakes could make a large difference in recoil.

With lightening my GII up by about a pound (barrel recontour), obviously felt recoil is going to increase. Even before the barrel recontour, the recoil was significant IMO (worse than a buddies 30-06 IMO, partially due to no buttpad I'm guessing), enough that keeping the scope on target after the round was fired was impossible.

I ended up with the M4-72 brake, because at the time, that was being shown as the most effective available.

I can tell you that without doubt, the brake made a massive difference. I won't go so far as to say recoil is at 5.56 levels, but shooting 130gr up to 190gr ABLR's with fairly stout loads, the recoil is significantly less. I can't put my finger on an exact, but I would definitely agree with testing that I saw indicating ~50% less recoil.

Yes, concussion and sound are also up significantly, but I would say to anyone that doesn't run a brake, and has no reason not to, try one. Especially one of the ones seen in various tests to be very effective.

I've tried quite a large number of different brakes, in a variety of calibers, gas guns and precision bolt guns.....and I agree that the M4-72 is one of the most effective.   The thing that bothered me specifically about the M4-72 however, when combined with a 16" carbine barrel, was the amount of gas directed back at the shooter.   The recoil reduction was great, breathing a snout full of gas on every trigger press...not so much.   Tried the M4-72 on an 18" barrel, and it became a non-issue as the extra 2-inches helped the angle of the gas expelled to bypass the shooter.

My current favorite brake is the AREA 419 HELLFIRE self timing brake.    The design allows for the easiest timing, as well as tool-less on & off for cleaning.   Certainly most .223 shooters don't spend much time removing their brakes for cleaning....mostly because the higher exit pressures from a .223 barrel tend to blow the crud right out of the brake.....not so much with other calibers and/or precision rifles.....but also because it's a royal PITA to have to re-time a brake after it's been removed for cleaning.   This problem is eliminated with the design of the HELLFIRE.

Both the Hellfire and the M4-72 are not inexpensive, but you do get what you pay for.  However, for a budget build, it's truly hard to beat a DPMS Miculek brake, which while it does not have a self-timing feature like the HELLFIRE, and is not quite as effective in recoil reduction as the M4-72, the Miculek brake is only $39.   At that price point, it's hard to argue with the amount of performance you get vs. the $$ spent.  In fact, you would be hard pressed to find similar performance from any other brake at even twice that price.

Talk to joshv06 in the ee. I bought a lot 308 tank style comp from his company. It is made by Guntec.. Recoil is gone.

Recoil is gone and so am I when someone shows up at the range beside me with one installed.

I've got a fairly cheap strike industries j-comp v2 on my 308, primarily because I had a v1 on my 223 and liked it.

The recoil reduction is significant. With the stock birdcage, I had internal bleeding marks on my shoulder after like 20-30 rounds. After installing the j-comp. I shot 50 rounds, and not a mark on my shoulder.

Great thing about the j-comp is that it doesn't throw fireballs, and concussion is actually quite tamed. Don't let the cheap price fool you, it's a stolen design that probably had a government procurement r&d budget behind it.