The Right Shot Size and the Squared Load
A look at the exterior ballistics of shot tells the tale: it is better to increase shot size than velocity for downrange wing shooting performance. Lyman's shows the drastic difference. For example, #7-1/2 shot launched at a muzzle velocity of 1330 fps has only .9 ft. lbs. of energy at 60 yards. Take #5 shot, launch it at just 1135 fps, and at the same 60 yards it retains in excess of 200% more terminal energy, 2.1 ft. lbs. Compared in a different way, 1200 fps #5 shot has more energy at 60 yards (2.2 ft. lbs.) than #7-1/2 has at 20 yards (2.1 ft. lbs.) when launched at identical velocities.
If you want to spin doves past 50 yards with authority, #7 shot beats #8 or #9 shot every time. Same way with pheasants, #5 (or even #4 shot) kills them quicker, cleaner past 50 yards than #6 shot. Over 40 yards of dove and pheasant hunting has made this clear to me.
All of this is predicated on regular, uniform patterns. No two guns pattern identically, no two chokes pattern identically and no two shells pattern identically. If we don't take the time to pattern, we are just "winging it," literally, and have no real concept of how efficient and effective our patterns may (or may not) be.
Shot deforms shot, primarily on initial setback. Many of the loads commonly used today are tremendously over bore capacity. They might pattern well in a specific gun, but the closer we stay to the "squared" shot column, the more efficient our patterns tend to be in more guns, particularly when using soft, low antimony, small diameter shot..
Moderate, highly efficient (near optimum) loads are exemplified by the 3/4 ounce 28 gauge load, 7/8 ounce 20 gauge load, 1 ounce 16 gauge load and 1-1/8 ounce 12 gauge load. Often, adding more small, soft shot in any of these gauges does not make for longer killing range patterns, but looser "blown" patterns with less effective killing range. However, with very hard, high antimony shot this may not be the case, nor is it true with buffered loads or large diameter shot.
Only the pattern board can illuminate this for us. Squeezing 2 ounces of shot through a 12 bore might give us satisfactory wing shooting patterns, but too often the converse is true. Only trigger time on a 3x3 foot sheet of paper, or a re-paintable metal plate can show us what is going on down range. An important component of pattern quality is density and uniformity at the fringe area, as almost all shotshell component combinations have hot cores.
Harder, high antimony shot gives higher percentage patterns, as does nickel-plated shot (the nickel plating serves as a lubricant). Buffered loads certainly work, particularly with the heavier shot payloads.
The shell is the primary component to quality patterns. It isn't that back-boring, forcing cone work and similar efforts cannot work, but they can just as easily harm patterns as help and metal is hard to sand back on.
It costs manufacturers no more to cut a long forcing cone than a short one, so why would they not all have long forcing cones? The reason, of course, is that the benefits are dubious and not always easily discerned. There can be no uniformity in a chamber that accepts 2-3/4 inch, 3 inch and 3-1/2 inch shells interchangeably, yet that does not seem to bother us a great deal.
True "back-boring" lightens barrels, and was designed to pull a few ounces out of lifeless, "dead" barrels to give us better balance and handling. Factory "back-bored" barrels are not really back-bored at all; they are just larger pieces of pipe. No way can so-called "back-bored" factory barrels compete with the pattern efficiency of a larger gauge. That gives a shorter shot column for a given payload well beyond what back-boring can possibly achieve.
Shotguns are for the birds. If there is a trend in what we are doing, it would be using more shot than we should and more choke constriction than we should, a trend that should be resisted. Instead, we should be focusing on quality high antimony (hard) shot, moderate (square) shot loads, and defining personal patterning performance in our own individual guns. That's where most of us fail to put in the time, but that is where the major benefits can be quantified and used to bag more game, cleanly.
Copyright 2006, 2016 by Randy Wakeman. All rights reserved.