If one wants to read the best discussion of Shotstringing ever put into print I recommend a copy of "The Modern Shotgun" by Sir Gerald Burrard. This is Major League work, Brister's is High School in comparsion, I have both & have read & studied both, this is not hearsay.
To sum up Burrard's recommendation was "Unless" you were shooting at birds beyond 40yds, flying faster than 40 MPH & at 90° to shot line, "Ignore" shotstring. "IF" you requirements exceeded these limits, then shoot for a 10% increase in your minimum pattern requirements for the bird in question. Thus if you would have ordinarily figured a need for a 100 pellet hit in the 30" circle, shoot for 110 & forget it (This on your stationary target).
He shot at a large metal plate attached to the side of a vehicle in such a way as to protect the driver, much smarter. It was also found the forward & central portion (The most effective portion) of the "Swarm" of shot was least affected by stringing, this being mostly from the deformed & lagging pellets & those from the outer limits of the pattern. He also found virtually no diference in shotstringing between the conventional British game load of 1 1/16oz & a heavier 1¼oz load, though these obviously had a differt length of column in the bore. Using these two charge wts in the 12ga for comparsion a 20 ga would have virtually identical column lengths using 3/4 & 7/8 oz respectifully.
The main thing brought to light by Brister was that modern plastic wads, super hard shot, & buffer mat'l could eliminate a lot of the deformed shot effectively bringing them into the main pattern.
One item on buffering, Brister spoike quite highly of ordinary Flour as a buffering agent. This was later shown by Don Zutz that under some conditions flour could cake & adhere to the case walls resulting in decidedly "Dangerous" chamber pressures. Do not be tempted to try this for the purpose of enhancing patterns.
