The act of posting multiple times on a bulletin board in order to hit a post number target before your fellow avatars
Example 1
Poster 1 -
"Take teh bu%%er Hammy"
"Take teh bu%%er Hammy"
"Take teh bu%%er Hammy"
"Too late - 10000 is mine!"
Poster 2 - "You machine gunning tw@!"
Example 2
BB Poster 1 : "I see post 250000 is coming up on the THUS thread"
BB Poster 2 : "Aye - i'm gonna machine gun that fecker"