I have a Marlin 1894, 20" barrel in 44 mag. I've got about 150 rounds through it. It has the micro groove barrel and I've been primarily shooting hard cast bullets from Buffalo Bore ( 305 Gr LBT ). I'm getting about 2.5 " groups at a hundred yards. I'm certainly hoping to improve on that. I've tried several brands and jacketed bullets etc but it seems to pattern the same no matter what I feed it. Any ideas ? I do want to get one of the Wild West Triggers installed as the factory one is pretty miserable.

Microgroove barrels seem to handle bullets weighing 200 to 240 grains best in the accuracy department. I would guess the 300+ grain bullets do not stabalize very well. Try some 240's and see how they shoot.

Thanx for the idea. I'm going to the range tomorrow to do just that. I picked up a box of the Ultramax 240 grain RNFP. Has any one ever used this brand ?

You may want to try a lighter bullet and see if they shrink. I suspect the twist may favor lighter bullets typical of factory jacketed loads. Of course, if I can get 2.5" groups from my little iron sighted 1894P, I'm one happy camper.

I have tried a few lighter jacketed loads. I really want to use hard cast bullets. The jacketed bullets I see for the 44 mag are always HP's. They make a real mess on a whitetail. I'm useing a scope on a solid bench so I'm hoping for about a 1.5" average group. I'm not sure what you mean when you suggest checking them to see if they shrink. Do you mean weight or diameter ??? I can recover bullets when I shoot at my camp but thats out of a dirt embankment.

I was refering to bullet weight. More like the 240 grains being the "standard" .44 magnum bullet. LeadHead has a cast 250 grain Keith and a 270 grain LBT that being lighter may give better groups. As for diameter, going as large as can fit in the chamber may also help with the micro-groove barrels. Also, Speer makes a nice 240 grain jacketed that is not a HP.