I used the LBT LFN 300s in my M-94 Trapper without troubles, but I did trim my brass back to 1.240". I did this to allow the use of the Lee 340F bullet because with full length cases the ogive of this very blunt bullet hit the lands when crimped in the crimp groove.
I tested some pretty heavy loads in my M-94, and I'll not list them here - that was years ago when I was more foolish. Milder loads which worked well but are under max published loads were:
300LBT/26.0/RL7
300LBT/21.0/W296
340LEE/25.0/RL7
IME Ruger-only loads listed in the manuals, using the slower powders, work very well. Remember that just because the M-94 is a rifle doesn't mean you can go crazy with powder charges. Besides, this light little carbine kicks a lot with the heavy bullets....