I had a slip over the sight flash hider that had brake holes and never seemed to add to the noise level. I’d just delete it if I thought it did. 7.62x39 doesn’t exactly have what I’d call recoil tho and I’d rate the noise level below that of 5.56. Have you considered just removing the brake altogether?
Ah, gotcha. In that case, if there’s a linear type of brake in .30 cal like the Levang linear brakes I use on some of my 5.56 stuff I have to say I like. I saw a study done a few years ago where they measured recoil/muzzle flip etc in several brakes and the linear style brakes were middle of the road, but everything goes out the front so they are easiest on the shooter (and likely anyone else nearby).The barrel was cut and threaded to help with accuracy not for recoil. Also had some trigger work done. Both helped.