Hard to diagnose without an "eyeballs on"...

GROUPS: Depends on bullet weight, composition, etc. No big deal.

GRIP: You can't be shy with a .44 mag. It must be a firm hold, but not a "death grip". Allow the curl at the top of the butt frame to seat into the web between thumb and forefinger in the most natural position. (With my medium-sized hands, I have to lock the tip of my thumb about half-way over the tip of my middle finger for a nice, positive grip. I'm not a fan of the "thumbs pointing forward" grip that seems to be en vogue, nowadays, as it gives me less contact and control.) I like to get the first joint of my trigger finger hooked right into the edge of the trigger for good contact and control.

ARM EXTENSION AND ANGLE: Especially with heavy magnums, I like ---and teach--- that a slightly-bent-at-the-elbow arm position ---with both one and two hand firing--- will help manage recoil better than a full, horizontally straight, arm extension. I allow some of the recoil to push the barrel upward a bit, instead of taking all of the force directly back in a straight line. Hand, wrist and arm, ideally, should align vertically as straight as possible to the shoulder. But that is not really physically possible, and we all have to make adjustments accordingly.

STANCE: Relax. Tightening up like a guitar string will cause erratic groups, bad habits and will fatigue you. Shoulders forward a bit... lean slightly to target, putting your reactive weight where it will do the most good. A slight bend at the waist, a medium-wide stance (whatever works best for you) with knees flexed. Settle in like a batter in the box at home plate, but do not go rigid. Move your feet to a comfortable position. Bring the gun up to get your sight picture and make adjustments that fit you. Practice dry until you think you have it, then start pulling the trigger fluidly and see what happens.

I shoot my M29 8 3/8" DX regularly and it is an absolute sweetheart to shoot with the Pachmayrs that came with the full kit, and I am not a Mongo-sized guy.

Have fun. I hope this gives you a little help.