I was shooting in a local 2 gun match w/ my AR A4 Clone. The stage was 5 different stations. Three steel reactive targets, 2 rds each. By the time a got to the 4th and 5th stations the reticle was looked canted. I have the ACOG in a Larue Mount. I checked to see if it was loose. It was nice a tight.I fired a lot of rds because I was kneeling, fogged glasses and heat distortion, so I was missing. After the barrel cooled down the canitng seemed to straighten out. I am guessing it was the heat from the barrel. The safety officer saw the cant as well. thoughts?