I've done lots with .44 mag gas check bullets and just shot some with this Rossi Puma in .44 yesterday... My bullet is a different one but still, when I was shooting them through a S&W 29 I didn't use gas checks because I loaded down to .45 auto spec for enjoyment of shooting it. You can also use .44 special loads, just refer to them in the book. You won't enjoy white box ammo one bit, not even in a light carbine. I keep the loads down and when using revolver I didn't get leading without GC, rifle I have them a bit higher and use GC to keep them flying straight. I was loading Unique and 11 gr but couldn't get them to work right even with GC, seemed to be blowing them right through. I reduced to 5.5 of Bullseye and they work fine. This was also what I used in revolver without GC. Revolver tends to have a more aggressive rifling. I shot a Desert Eagle for some years in .44 and didn't use GC there either, no leading and positive operation even though it has a polygonal rifling... By the way, I cast mine from straight wheel weights. That's a bit softer than the mixes. Weighs a bit heavier but don't worry, no disasters pending. I size to .429 and don't see the need for powder coat expense. I use the lubes as outlined by Lyman in the manual.