Felix, I use a full size LBT WLNGC and the Lee 310 gr. in my Marlin and it feeds perfect. I have never had a hang up. I have a round nose with a small flat meplat I designed for silhouette that is just a few thousandths longer and it hangs up. I shortened 50 cases just enough for them to feed these boolits.
I repaired a Ruger semi auto some time back for a friend and wanted to see what it would do with LBT's. Had to shoot it single shot. I compained to Ruger about the short magazine but they never change anything.

If anyone is contemplating cast boolits for the 44 lever action for sure, or maybe the simi-auto too, Ruger carbine(s), you should be extremely careful of overall cartridge length. The design should be as close to the jacketed varieties as possible, with a nose resembling a smooth, rounded (cowboy) boolit, with a meplat of sufficient size as to cut the boolit length down for realizing a shorter nose, in keeping the crimp groove as close as possible to the base of the curving ogive. In other words, a deeper seating boolit. I had Veral Smith do a carbon copy of the Speer 240 jacketed, but with a shank longer to make for 250 grains, including two lube grooves. IN OTHER WORDS, a Keith won't work in the Ruger carbines. You need a LFN or WFN round nose style. ... felix