I have been loading the 44 Rem mag since May of 09 for my SW 29 and recently picked up a Marlin 1894 in 44mag. Im currently loading 6 grains of trailboss for my pistol loads. I havent had time to test velocity or accuracy shooting these loades out of my rifle. What can i expect? I have found some 44 rem loading data for rifle but the powder suggestions dont match the powders i currently have (trailboss, Autocomp, 2400) any suggestions?

Ken Waters pet loads list 21g of 2400 w/ a Horn 240g JHP as being near max and a "good load" in both revolver and carbine. 1407 fps for revolver/ 1702 fps in 20 inch carbine.

Watch using Ken old loads The powders he used then and the ones I use now tend to run on the hot side. reduce a grain or two and work back up/

I use 19-20grns H110 for my RSBH "7 1/2 and in my "16 Winch. Trapper under 300grn Cast Core/Nosler JHP w/ magnaum primers for really good accuracy and terminal performance. Sorry you can't ask the pigs, lol. From 350lbs to 85 lbs at 100yds. Just depends on what your guns like. For instance, mt RSBH loves 300grn Hornady XTP's, rifle doesn't. Settled on the Cast cores. For low loads I use 8.0 grns of Unique w/ 240grn Laser cast for fun and accurate shooting. Been reloading the 44 since 1987, just my 2 cents.

If you load your cartridges to perform in your pistol with what powder you have you will be ok as far as pressures in the rifle.
It might surprise you and like the charges.

6.0gr of Trail Boss with a heavey jacketed bullet could lodge in a long rifle barrel if velocity is 750 fps or lower. Alliant 2400 works well in a 44 mag.