lever action rifle, or m1 garand or even an m14. All are semi automatic with the exception of the lever action. Precision is my choice, as unlike in video games two or less shots to vital organs (head, torso) could put someone/thing down for good. Automatic weapons would be a waste of ammo, unless you put it into a burst or semi-auto fire mode. The only problem using an infantry rifle on semi-automatic is that it lacks the accuracy and power that a designated rifle would use. I would completely avoid sub-machine guns. My pistol choice would be a M1911 PDP.
My fursona has a special ability that allows him to be very agile, so i would use that ability. His agility allows him to move quickly, quietly, and allows him to avoid bullets to some extent, but not completely. Also, he wields a s&w .500 double action, along with a short katana.