This also helps:
set input leftmouse debug gpf
If anyone is wondering about that axis stuff in shotygun's set input command, it's changing the mouse sensitivity scaling to 3.5 from UT's default 6.0 so basicially making your mouse sens nearly half of what it is normally without changing your mouse sens value that you see in the options GUI.
Default: GUI value 3.0 will be scaled to 18.0.
Shotygun's: GUI value 1.0 will be scaled to 10.5.
If you set your mouse DPI to a very high numbers lowering these values can make tweaking your sensitivity easier so there isn't such a big difference between GUI 0.15 and GUI 0.14 for example.
