Why Shot String Does Not Matter
Often when attempting to extol the virtues of a gauge or shell, the notion that shotstring is somehow of tangible importance is often touted. Perhaps it is cited because most folks cannot easily measure shotstring. Performance claims that cannot be verified are some of the easiest to make.
A complete database of shotgun patterns will likely never be generated. It has been estimated that it would take 18 billion patterning tests, equating to 8 million man hours of work: and this estimate did not include a shot-stringing study. The December, 1927, American Rifleman gave summaries from L. C. Weldin (ballistics engineer, Hercules Powder) that showed pattern percentages from 19-95 percent with the same load and choke based on 4,000 patterns.
In the October, 1946 American Rifleman a difference of 20% between minimum and maximum pattern percentages was tabulated. Oberfell & Thompson (1957) pulled that in to about 10% variation, assuming same brand of shell and same gun. That remains as close a generalization as can be stated to the present day.
Despite the automatic vagaries of any statement about shot string, Major Gerald Burrard explained it well, and discounted it after his tests. Though a several foot long shot string exists, as the shot cloud is moving ten times (or faster) than any game the shot cloud can only string a matter of inches: a 5 inch shift of pattern center at 40 yards was documented with a 40 mph moving target at right angles. Oberfell and Thompson (The Mysteries of Shotgun Patterns) found the same, finding that it was no more important than the accuracy of the hold of the shotgun itself, and with the 10% variation from shell to shell became even less worthy of concern. This is for direct crossing shots. It is naturally of no concern for outgoing or incoming targets.
Bob Brister (Shotgunning, Art & Science) gave some treatment to the matter, being able to shoot at his wife driving the family car towing a long paper target. However, his tests were outdoors, ignoring actual shotshell patterning deviations. Finally, and most recently, E. D. Lowry revisited the subject in detail, and set the matter to rest for good, concluding that Major Burrard was right all along.
ShotString remains more fable than of tangible value, joining back-boring and gauge selection within reasonable limits as being at all meaningful. Yes, a shotstring has at least the potential to move your shot cloud's center by up to 4 or 5 inches or so at 40 yards. To get excited about that, limited only to faster crossing shots, would require us to somehow ignore that gravity often nets us over 3 inches of drop at 40 yards, and the pattern from your next shell can easily show a 5% loss of efficiency.
Maybe we would like to forget that shotshell shot is the infamously ballistically hideous roundball, with just a 10 mph cross-wind moving our killing pattern far more than any imagined shotstring ever possibly could? Nothing yet approaches the tangible value of load selection by personal patterning; that is shot with no strings attached.
Copyright 2006 by Randy Wakeman. All rights reserved.