I have seen them affect accuracy on some guns. Especially if the machining is not good. Basically if the brake is machined off, it can cause turbulance on the bullet or can cause inconsistent recoil so when the bullet exits the muzzle it might be closer to one side of the brake than the other, causing pressure differences. I have especially seen this on a traditions inline.
They can be difficult to clean. Added hassle and collect bunch of solvents. I have seen rust from this.
Lastly, makes the gun insanely long for pratical carry. I got friends that swear, they won't take abuse from a rifle and loves them. I figure if I can't shoot it without, I have no business with the gun. There are alot of alternitives. Good recoil pad works wonders. Also you can get a shoulder pad for the range. In the field you won't notice the kick that much or I don't at least.
I have a BAR with the BOSS muzzle brake on it, and I love it. However, it does make it insanely loud compared to a non-ported rifle of the same caliber. Wear some type of ear protection if you value your hearing, especially if you hunt out of box type stands.
i have been hunting for the past 14 years without a muzzle break and unfortunately when i took a hearing test a few months ago it was discovered that even
without a muzzle break on my 30.06 it had depleeted my hearing almost 25%.
my dr. told me that hunting rifle going off will infact damage your ears.beacuse the noise is almost 200 decibles when 40 decibles will start to damage ears. i am getting a muzzlebreak on my new rifle and i do intend on buying some game ears so
the noise of my break wont make my ears ring.
I have been wearing hearing aids since age 38. Nothing gets one's attention, concerning hearing loss like needing hearing aids just to carry on normal business in one's life. That said, no one should engage in shooting without wearing the best hearing protection available. I wear foam ear plugs and ear muffs when I shoot.
The real value in using a muzzle brake is that using one lessens the chance of getting the crescent cut in one's eyebrow, caused by rapidly mounting and shooting the rifle, without having same seated tightly into the shoulder. I can handle firing magnum rifles without a muzzle brake, but I prefer the brake for effect of damping down that sharp recoil.