That aught to play havoc with grouse, whats the FPS, and max effective range of those dudes?
They're almost impossible to chronograph accurately. But, I estimate they're doing 700-800 fps, depending on how well the nitro cards seal. Some of the hotter loads may be exceeding 1,000 fps, but rotating the cylinder in the revolver is very difficult after they're fired (due to the "shoulder" pushing the case head against the rear of the frame).
The lighter loads are good for about 20 feet, max. Beyond that, the 'donut hole' in the pattern is too large. The hotter the load, the quicker the pattern opens up.
I figure 15 feet is about as far as I'll push it. These loads are only used for "targets of opportunity" while chasing Elk. Since Ruffed and Dusky Grouse usually don't flush until you're about 5 feet away, in that terrain; it makes 10-15 foot head shots pretty easy.
I would prefer
a "bird and ball" duplex load, but they aren't exactly legal for upland game. (#4-6 shot under a 44 caliber round ball)