[Para Bellum]

I agree with most of the above, but still:
a skilled oponent can block and turn a knife attack. Try blocking and returning bullets...

recently in my area a plainclothes LEO was assaulted and stabbed into the somach when he left a train. he pulled his 5shot .38Spl snubby and fired all rounds into the BG. The BG died the LEO survived.
When ambulance and uniformed police arrived the attacked LEO was sitting on the ground, still clinching to his snubby repeatedly pulling the tirgger click-click-click until the paramedics took it from his hands...
IMHO fighting a knife with a knife is much harder than fighting a knife with a gun (at any distance).