I had one of the early 1894s in 357. It was a real shooter. I had a cheap 4X scope on it but it did just fine with open sights at the distances I shot with it. I killed several big Idaho mule deer with it, all within 100 yards. I loaded the Speer 180gr fn bullet with the load that is in the Speer#9 manual under Rifle data. You can't crimp in the canalure because it makes the overall length too long. I used 38 brass and it would crimp good enough to work.
Looking back, and also looking at newer data the loads from that manual may be too hot for a marlin. They were developed in a converted Win 92. There are better bullets to use now days. I would stick with a 180 gr bullet. The XTPs are good and so are the Remington 180gr sjhp. You can get the Remingtons from Midway at a really great price. My oponion is that most of the 140 gr jacketed bullets are just too lightly constructed to get good penetration. In that barrel with the micro grove rifleing, to get good accuracy at the volicities you need to shoot deer, I wouldn't use a cast bullet. They shoot good at low vloicities but not at higher volicities. However, you could try some of the really hard cast 180gr cast bullets and they may work fine. It may pay off to try some 180fr Laser Cast.
I hope my rambling helps you,
Sixgun
