I have read in a post the microgrove rifleing in a 44mag model 1894 will have leading issues with cast bullets. Is jacketed the only bullet to load in this rifle?

1894s have Ballard type rifling.

Not all 1894 44 mag's had Ballard rifling. I believe that the 1894S had Micro-groove rifling. There was also a 41 mag, the 1894FG I think, that had Micro-groove rifling.

Contrary to what you might have read, accuracy, and or leading, will not be an issue in a micro-groove barrel as long as you keep your velocities down to cast bullet numbers and you use the correct size bullet. You will need to use oversized bullets to attain the best accuracy along with little to no leading issues.

Don't give up on the microgroove before you try it. I have two friends who have the older Marlins with microgroove in 44. They both have had good luck with lead. I know one of them shoots softer, one in 20 or softer, and it works well, no leading and good accuracy with moderate to fairly stiff loads. I will check, but I believe the other guy just buys his lead bullets. I'm not sure of the diameter on either. Search for the title "From Ingot to Target" on the web. It gives a good overview of casting and what causes leading---too slow, too fast, too hard, too soft, lube, diameter and other factors. Give it a try, you might be surprised.
Jon.
Big Wonderful Wyoming

Ojaileveraction wrote: ↑Wed Oct 25, 2017 10:06 pm 1894s have Ballard type rifling.

Some do, some don't.

It might be interesting to slug your bore. Marlins often have slightly larger groove diameters than some other .44 firearms, so they like bullets slightly larger than the usual .429"; .431" seems to work better in them.

The two guys I know that have microgroove rifling bought theirs in the 1970's. I bought one in the late 1980's and it has Ballard style. I spoke with my friend last night and he said if you haven't slugged your barrel to do so, his is at .429 and he is shooting the coated lead bullets--commercial @ .430. He said no leading and good accuracy. The biggest issue I have with mine and I believe it would be the same as yours---mine has a very slow twist and I can't shoot Keith style bullets over 240 grains---they are too long and have to be seated to the top of the band to cycle in the action. And when I single load them I found they are not consistent. Four or five will go in a nice group and then the next round will be way off---like two feet and it will be keyholed in the target----I think it's the twist. The only heavy bullets I can get to shoot consistently are flat nosed bore riding designs. I'm betting yours will work fine with lead, it may just take some tinkering and measuring to figure it out. Good luck.

Forgot this. It's nice to have a bore scope---the new automotive bore scopes work good---to determine where the leading is forming in your barrel. The area it forms is an indicator of what is causing the leading. The "Ingot to Target" article has a good overview on this.

My two micro 44 mags shoot 240 gr cast lead, plated, and or fmj very good if I keep the speed down. For PC CLA they work well. I shoot them sometime and my scores don't change. I tried to make it work for CLA, but it was a no go at the turkeys and rams. No matter what I loaded I could not get a group on the rams. The ram group was as big as a 55 gal drum. The turkeys were not much better. Slug your barrel to see what size bullet you will need.

History of the Marlin MiroGroove
http://www.lasc.us/FryxellMarlin-MicroGroove.htm