A 4" N-Frame 625 S&W will not fit in the box without grips on it, even if it is a Mountain Gun.
A L-frame 4", 686, etc. will fit in the box with round butt grips only and require scratching out a little groove in the box wall to clear the front sight.
Of course, revolvers do not have to fit in the box but I find this information interesting as an anecdote.