The 265 gr FTX (#4305) is intended to be used in .444 Marlin, while the 225 gr FTX (#44105) is intended for .44 Mag.
Either can be loaded in either cartridge, but check out the COAL, cylinder length, and crimp groove location before loading any. The FTXs have long noses, and many cartridge won't work with them without trimming the brass extra short. (In .444 Marlin, for example, the brass must be trimmed from 2.225" to 2.065" [0.160"!] in order to use the crimp groove and prevent feeding problems caused by the case mount hanging out past the ogive.)
Hornady changed the jacket of the 265 FTX about four years back, after getting too many complaints of it being too prone to fragmentation and losing the jacket. It's pretty much a tipped "Interlock" now.
Terminal performance is now about the same as the original 444 "Interlock": the 265 FP (#4300).
I still won't touch it, though. Friends don't let friends load short brass.
The 225 FTX? Not a chance. Way too 'soft' and fragile for my tastes.