Someone gave me a clamp on brake for the M44 that locks on behind the sight. While it *seemed* to have some effect, it quickly destroyed the hinge of the clamp, rendering it junk.
Seems to be made out of pot metal of some sort. I'd not waste a dime on one, personally, and since I'm now shooting lighter cast loads accumulated recoil from a long bench session is no longer an issue. I only use the aftermarket rubber recoil pad to increase the length of pull.