Shot String And Waterfowl Hunting Ballistics
January 07, 2011
Tighter chokes throw longer clouds of pellets.
Shot string is a critical component in waterfowl hunting ballistics. More openly choked steel generally has a short string, which requires the shooter to be much more precise to hit the bird.
Ballistic greats, such as Bob Brister, whom I was lucky enough to spend time with and learn from, have studied the effects of shot string. Larry Nailon, choke builder and ballistics researcher, also contributed to my learning curve. Brister and Nailon positively confirmed that shot string exists in varied levels, and lacking that effect, hitting much of anything moving through the air would be quite difficult.
Recently, a few readers took me to task for suggesting hunters could learn from simply watching shot strings lay down on mud flats, snow or sheet water stands. I had been simply giving some reference to downrange performance by various loads and chokes as I saw them. I'm not a scientist, and my research for the past 45 years has been lacking a slide rule and white coat. I know laboratory-generated ballistics research people who do a good, if not outstanding, job but who have never fired at a clay bird or warm target in their lives. Some don't even like shooting guns. In my camp, however, the friends I hunt with shoot thousands of shotshells at clays, spend countless hours over decoy spreads and kill large numbers of game birds each year. As such, these guys have become observable learning tools for me in the field, or as is often stated, "the school of hard knocks and loose feathers."
Once, a guy called me to ask where my laboratory was located. I answered that it is in the back of my pickup truck with the chronograph equipment, target boards, range finders, roll paper and cases of different loads. It's called field setups and intuitive thinking, and it is a process even the slide-rule boys are getting the hang of more and more every day.
When you hunt year-round professionally, work over problems on a shooting range between hunts and record time on a word processor, you tend to develop a third eye in terms of seeing what could be referred to as the ballistic obvious. Shot string is one area of the obvious to me. Here is my take on the subject.
Mechanics of Shot String
Even 30 years ago, we observed that flat pellets come into a pattern board late and quite far off the mark. Using different-colored paint on pellets, we could see that rear pellets in the payload were hitting more toward the target center core, while most of the fliers were pellets that had started out in the front of the pack.
Why did this happen?
Well, drafting like a racecar was always thought to be the culprit, and modern high-speed photography has generally confirmed it. I use the term "generally" because shotshell science changes year by year.
When shot deforms, it tends to string out. That's why full chokes distort the payload and throw longer shot strings. With soft shot such as bismuth or lead, the situation is compounded because flat-sided shot become fliers and leave the pattern early during the run downrange. String length becomes longer, and some pellets are slowing down faster than others. This is a simplified explanation, but it helps shooters understand what is going on beyond the muzzle.
Recently, I had a discussion about shot string with a company that is doing choke research and testing for me. Mike See, inventor of PatternMaster chokes, came up with a very basic ballistics observation. See was at a three-gun shooting event in which shotguns loaded with fine lead shot had to be used on a steel silhouette target. Guns shooting more open chokes, which delivered faster expanding patterns because of compression, were not knocking down the steel targets well. When PatternMaster (stud-controlled) choke tubes were used, the core pattern became denser and ran a shot string, as stud-designed and ring chokes will. The steel targets dropped like quick silver.
According to See, the tubes saved the day and won that element of the three-gun event. What happened was basic field science come to life. A lot of shot hitting steel very fast in a short time did the trick -- just like slapping a big mallard, ringed-neck pheasant or goose would on a fall morning.
When long, drawn-out shot strings slammed into the steel plate, the effect took place over a longer timeline, so the mass of shot didn't have the net advantage of working as a team, but only as incoming individual elements that alone retained very little energy.
When you shoot enough patterns at a hard board, you develop a sense of what that load is doing by the sound duration of shot slapping the board downrange. A clatter or a solid whack against the board can be the difference between a sick, slow-moving shot string and a hard-hitting cloud of shot getting the job done.
Moving to the clays course, a working lesson about shot string was revealed during a shooting school put on by Vicky and Gil Ash. When I attended, I was told to forget about leading the bird, but instead watch the clay target keenly and even work at observing the leading edge. Simply mount the gun correctly and keep it ahead of the bird. Shot string would take care of itself in terms of the remaining elements of a clean, well-exacted shot on that moving target. This was so evident that at one point in the class, a shooter was asked to shoot crossing left to right clays at a 15-yard station. After pounding a dozen straight, Gil Ash told the shooter that when he gave the command to close both eyes, but just keep swinging the barrel and break the bird. He broke the bird with perfection, turning it completely to black dust.
Short Shot Strings
Hunting with my pals this spring gave additional clear evidence as to the net effect of shot string, or in this case, the lack of it. Black Cloud ammunition was under test by Tyson Keller, Martin Husby and me over 300 snow goose motion decoys. The morning shoot had gone well, with a 1.5 round average per shotshell to bird-on-the-ground kill ratio. The Black Cloud No. 2s were devastating. Every goose I checked was hit hard and often by the ultratight, sabot-controlled payload.
Keller is an expert sporting clays shooter who was selected to the five-man state team from South Dakota and has shot over 100,000 targets in seven years. As a warm bird gunner, he is one of the best I have ever seen. Husby is a fine shooter, too.
Late in the day, large flocks of birds dropped from high altitude, which required different leads and shooting tactics. All of a sudden, all three of us went stone cold. At one point, four in-your-face geese left the spread untouched.
Coupled with a very long day in the field and reduction in timing due to fatigue, we were
just falling off the mark. Lacking assistance from long shot strings, the results were showing up as missed birds. While Black Cloud loads are deadly to say the least, they are also not as forgiving when it comes to relying on a 10-yard string of pellets to get the job done.
Shot string is not only a factor in terms of load and choke quality, it is also the major element in your pattern that helps you hit birds overhead. If you discount shot string, you are setting aside one of the very best tools you have to hunt waterfowl or upland game.