I have the tungsten hammer in my M3 and M4 from the get go with no issues. I do not run my airguns maxed out The M3 is a .22 shooting the 31.2 grain NSA at 1000 fps and the M4 is a .25 shooting the NSA 34.9 grain @1013 fps. My Dynamic 600mm .22 shoots the NSA 28.5gr @ 987 fps. I haven't had any issues with the Tungsten hammers. The hammers are the current weight not the heavier early Tungsten hammers.