I was in the Army at the time out in Canada we were living in tents in a very big forest .
I was on guard duty at the time there was six of us in the guard tent at the time.
It was my turn to go out and walk round the time about midnight and very very dark.
The Guard sgt said"Come on Matcham your turn out you go and take your rifle with you.
So out I went ,I was walking along the path when I saw a person standing by a tree ,thinking to my self whats the hell is he doing out at this time of the night ,so I went up behind him hit him in the back with my rifle.and Said "WHat are you doing ,he turned on me ,it was not a person but a very big wild Grizzly bear ,!I turned and run back along the path with him running after me as I run pass the Guard tent I shouted "Bear behind me"! next thing I heard was alot of shouting and the bear had run into the side of the tent there were men running all over the place but I did not stop. And got away I had a rifle but no rounds in it.

Very true story.