I am about to take delivery of a Marlin 45-70 stainless guide gun and am wondering if it is possible to shoot black powder loads from it? I have already worked out a hunting load for this gun but would like to shoot black powder for fun if possible. Is there specific cleaning issues after using black powder? Any help would be appreciated.

I wouldn't do it. BP is so messy and so corrosive that you'll be forever cleaning your levergun & probably damaging it internally to boot. If you wanna burn BP in a 45-70, I'd recommend a gun with the fewest nooks, crannies, crevices and moving parts.......Trapdoor, Rolling block, Sharps. I loaded some BP loads with Goex and shot them out of my Trapdoor Springfield when I first got it. Leaves a miserable residue in the gun and the empty brass. When cleaning, a small drop of solvent with BP residue ran down the stock and streaked the 130 year patina of the finish (solvent alone won't do it). Now I shoot IMR-3031 and don't miss the BP. Maybe I should have tried Pyrodex or some other BP substitute. I suggest you do the same.

Please don't double post.