The nipple windows in the Remington are narrow and tapered, and the cash snail capper is too wide in the nose to seat a cap. Works fine on a Colt.
My solution, as others have done is to widen the windows on the cylinder to accept the cash capper, as it is the best one to use, since it will hold a whole tin of caps. This can be done, if you are careful and skilled enough, with a Dremel tool. Best done on a mill in a machine shop, open to about 5/16 diameter at the bottom, I used a 5 degree drafted cutter, but it can be parallel, angles just look a bit better on that gun. Tried a ball end cutter to get the Ruger Old Army shaped opening but it still didn't quite pass the Cash capper near the bottom.