Hello Gentlemen, Rob here from North Alabama. I going to chime in on this issue. I have only been wing shooting since 1982 so I am not a know it all. I do have alot of experience pattern testing mainly the different types of non toxic shot. Steel, tungsten iron, Hevi Shot, ITX, Tungsten Matrix, Alot of Bismuth/Tin which I make and finally TSS. I have sent Thousands of rounds down range at pattern boards since I was a teenager. I respectfully disagree with the esteemed gentleman from England. Yes shotguns shoot shot strings which is well known. However since a pattern board is 2D and the shot string is 3D some assume patterning is not worth while. Knowing your guns pattern is important because it can give you very valuable clues as to the over all density and especially the core density of your pattern as it responds to the different variables you introduce into your guns barrel or barrels. Namely, powder type, manufacturer and size, shot load size and material makeup, the various different types of wadding used and OP wads and OS wads. All in my experience can definitely effect patterns and shot strings. Core density is very important when shooting past 30 yards. Core density is the innermost 20 inches of your pattern from your POA or some say POI. If most of your shooting is done 30 yards and in then you want a nice even spread of pellets within your 30 inch circle and core density is really not important. However shooting past 30 yards requires good core density especially on large game birds like waterfowl (especially divers). One above poster mentions pellet strikes and overall averages within a 30 inch pattern circle which can relate directly to a loads performance level at a given range. I believe he is referencing the Olin Winchester tests that were carried out decades ago but have proven their worth in giving hunters a benchmark to go by here in the US. Mr. Ed Lowry has a shot program that is outstanding and uses the Energy Density formula which recommends for large waterfowl and pheasant sized game a ED of 235 ft-lbs/in2 within a 30 inch pattern at a given range. I have found this to be fairly accurate. This was a test that USFW did where they shot 4400 Mallard ducks at (controlled conditions) with steel shot, copper shot And lead shot. The internet link I have is dead now. The problem with this report however is it is for only 3 types of shot and lead is not used for waterfowling anymore. I do believe it is still s decent benchmark on the energy density regardless of shot type. Also as to patterning since I hunt squirrels which are stationary targets I find it worthwhile that I also have a good core density for these types of targets. In the end to each his own and I hope that everyone has good luck doing their own thing. I also might add that the program can be used for Muzzleloading shotguns and not just breech loaders. It does help to know the MV (muzzle velocity) or there abouts. I hope this helps gentlemen and I wish you all good shooting.
Peace
