12ga 870 express with a 28" bbl and a IC .665 choke all shots at 40yds 10" circle
#1- 3" 2oz #6's hevi             #2- 3" 2oz mag blend hevi
shot 1- 159                            152 
shot 2- 170                            195
shot 3- 167                            179
shot 4-  xxx                            176
Gun was deepcleaned  and then cleaned with bore snake every few shots, i also shot the #6's first. 
how do these numbers compare to others, and why would the numbers jump from the first shot on the mag blends, i do remember running the bore snake before i shot that shot?