I've been using 23 grs with the 429421 in 44 mag for many years now. It gives 1250 in a 6 1/2" M29, 1300 in my Redhawk. It is accurate in every 44 I've tired it in, including a Marlin carbine. Primers are round, cases eject easily. Like Hammerdown said, recoil seems to be less sharp. As I've said here many times, I believe 4227 is easier on the revolvers than 296/H110. I saw enough back in the silhouette days in magnum revolvers to know it is true. It gives a little up to 296/H110 in ultimate velocity, but not enough to matter. A magnum primer isn't necessary.