This one is a Marlin 1889 in .38-40...I don't hunt with it, but do love to plink. The peep, a Lyman IIRC, was on it when I bought it and someone had redone the stock and fore end; but the bluing and case hardening is original. She's a sweet old thing that hangs beautifully from offhand...and will toss beer cans around out to 100 if the shooter knows his business. The 2nd pic is a close up of the receiver area.
I use home cast 200 gr truncated cones designed for the .40 S&W and cast them as large as I can. The mold with straight wheel weight alloy throws them at ~0.404"...enough for that old black powder rifling to handle up to ~1200 fps. Hornady swagged flat points work as well, but at a lower pressure to keep from stripping in the rifling.
Best regards, Rod