I've been using a standard load of 16 grains of 2400 in several of my rifles and large caliber revolvers with good results. Reloading data is limited, but I recently worked up to 16 grains of 2400 in my .44 Mag with a 320 grain bullet cast in an LBT WLN mold. Recoil was heavy but the case and primer didn't show any signs of excessive pressure. I didn't chronograph the load, but expect it is in the 1000 to 1100 fps range.
Any thoughts on this load from others? As with any magnum load, I imagine a steady diet of these will be hard on my old S&W M29, so I will only shoot them occasionally.
My elephant killer uses a 318gr semi wad on top of 6.1 grs of Red dot. Not the magnum load you are suffering through. This load was not devoloped for power though. The NRA Hunter pistol course has Rams at 100m and I wanted to make ammo adjustments rather than sight adjustments. At 40m the chicken targets require a much different sight elevation and thence a much different load. For each of the four different distances I have a load. The Rams at 100m with this big ol bullet really dance. The same bullet with 5.0grs of Red dot will be dead on at 75m, no sight adjustment, the damm turkeys are at this distance. Both loads need a heavy crimp for good obturation. Since I seldom hunt anymore, nearly all my shooting is target practice. You are correct about your M29 suffering almost as bad as you will be after a good dose of your elephant killers. Check all the screws and have fun.