To the OP,
First off the powder you are using, IMR-4227, is one of the most UNDERrated powders for the .44 Magnum. IME it does not provide the velocities of W296/H110, but provides much better accuracy. When I lived out in West Texas lots of avid IHMSA shooters swore by IMR-4227 or H4227 for the .44 Magnum because it had less recoil, still had the velocity with 240 grain bullets to take down the 200 Meter Rams, and shot groups several inches tighter at 200 meters than W296/H110.
Ok to get back on topic, google search for information and pictures on a step down crimp. This is a roll crimp in which you seat the bullet into the case to where you barely see the cannelure/crimp groove of the bullet above the case mouth, then with the seating stem screwed out you turn down the crimping/seating die applying crimp until the case mouth is stepped down to where the case mouth contacts the bottom of the cannelure. The case mouth will appear stepped down into the cannelure instead of rolled into the cannelure. Buffalo Bore .44 Magnum Ammunition uses a heavy step down crimp in just about every load cast or jacketed.
I hope this helps. Please follow all safe reloading practices.
Just my .02,
LeonCarr