There was a short story, probably from the 1950's, about a man who goes to visit his grandfather or uncle, father etc. The man is confronted by a stranger, who tries to beat him up while walking to his grandfather's house.
Once he beats this stranger, he arrives at his grandfather's house and notices everything is different. After an argument the protagonist accidentally kills his grandfather. He then travels back in time to stop himself from killing the grandfather. He jumps out of a bush to stop himself and is subsequently beaten up and unable to prevent the killing.
I have searched all over Google. May have been originally published in "Amazing Stories" magazine.