I killed 29 squirrels last season with an old 870 12 gauge with low brass #6.Ive killed 9 this season with a stoeger 2000 12 gauge with high brass #6.I love a shotgun for shots under 35 yards,but where i hunt,the shots can be 60 yards,so i take the 17 HMR most of the time.I recommend u use #6 rather than #7 1/2,(with a 12 ga.)b/c u put so much shot in the meat,and it aint fun to chomp down on 1 of um!!!!!I like a full choke,but pattern with different choke/shell combination so u git the best pattern.Pattern at the longest range u plan to shoot,with me its 40 yards.good luck