As you know I'm a newbie caster, Sal, but my research tells me smokeless powder loads need less lube than black powder. Old moulds were designed for BP loads. New moulds are mostly designed with smokeless powder in mind and have shallower lube grooves. I'm sticking with the old BP style moulds and SPG for now and I'm not doing the 44 mag...yet. I think you'll be fine with this mould but may need a bit harder lube, one designed for higher pressure/velocity. FWIW SPG worked well in my 45-70 for loads up to 1500fps so far, maybe even higher.
Hey, you've got the moulds and cast the boolits, Sal. Give it a try! Let us know how it works. Richard Lee has forgotten more about moulds, boolits and reloading than most of us will ever know.
Life Member NRA, TSRA
Smokeless powder is a passing fad! -Steve Garbe
I hate rude behavior in a man. I won't tolerate it. -Woodrow F. Call Lonesome Dove
My favorite recipes start out with a handful of used wheelweights.