Shotgun Barrel Length - Barrel Length Comparison

I wanted to compare the spread between 4 different shotgun barrel lengths and 3 common loads. Loads used: Winchester - 2 3/4 - #8 Federal - 2 3/4 - #4 Rio - 2 3/4 - 00 Barrel lenths: 14 inch - cylinder 20 inch - cylinder 30 inch - full 36 inch - modified