In a Uberti or Miroku 1873 semi wads will work flawlessly if seated properly to work or the brass elevator has been altered a bit to accommodate shorter AOL rounds. Marlins are a bit more finicy to feed SWC rounds. If the meplat of the slug is of the large size they feeh very well but if they are of the "small meplat" model resembling a crayogragh crayon point they will require a double clutch or two.
back to the 1873's, look at the front of the brass elevator and you will see a slope cut into it. With a shell of the same length as you use laying in the trough, if the tip of that bullet protrudes out past the lip of that slope then you are good to go with that bullet & lenght. if the lip of the slope is open for the next round to come back onto it, it will not allow the elevator to lift as it has too and your jammed. That elevator slope is easilly altered for any bullet lenght you desire to use within rreason by putting in a milling machine and increasing the slope back...another tip now, shorten your magazine spring when you have it apart, those springs are usually 8 inches longer than they need be from the factory ( I always set any mag spring to be 4 fingers width sticking out of the tube0 thats all you need to push the last round onto the elevator.
using an 1873, it doesnt matter what contour/ogive the bullet has, either RNFP or SWC big or small because when the elevator lifts the shell up to in front of the bolt, it is a straight feed into the chamber. It just needs a slight bullet nose slope for final alignment with the chamber.
The Marlin or any other Winchester model or derivitive are a different breed of cat that have an angled lifter to feed cartridges so the bullet nose does make a difference when making the angled corner to aligne with the bore.
