I recently tested my 870 Wingmaster 12 gauge to check the shot pattern. Using Federal 1 ounce 7 1/2 2 3/4 shells, I stepped off 40 yards and fired. The barrel is an improved cylinder and according to the chart on the target, this choke and load combination should deliver 45% of the 350 pellets in the 30" circle. I counted 223 pellets in the circle which is 63%. I fired a second time and counted 220 pellets. Am I to assume that I have an above average shotgun? Do more than 2 shots need to be fire to get a true indication of how well a shotgun patterns?