Depending on how short you load the Russian, it can be done two ways. If longer 240 grainers are used, sometimes steepening the bevel on the lower front edge of the carrier will work. The other way is to use the set screw method that Terry Schultz (Major?) writes about. A set screw is tapped in from the side, protruding slightly into the bottom channel of the carrier. A small portion of the bolt face is removed to clear the screw. The screw stops the short round from going all the way in.
This was developed by re-enactors to load short blanks in there Henry rifles. I have one of Terry's blocks and it feeds crimped 45, 44-40 and 38-40 brass into my 45 Colt Henry. It will cycle 45 Schofields with 200 grain bullets with the original lifter, but needs the modified for Schofields with 180s.