Well, yes, but length is not the only factor. The cartridge has to "turn the corner" to get into the chamber, and while length is one factor, so is the chamber-mouth diameter relative to the cartridge neck or seated-bullet diameter. The .577/.450 slips in easily because the relatively slim neck has plenty of lateral movement in the wide chamber-mouth.

An extreme bottle-neck case can be much longer than a slim straight-wall case, and still fit.

Clear as mud?