Clay Target Q&A
With Russell Mark, Olympic gold and silver medallist
Questions: russell@corporateshootingstars.com.au
Q I have been involved in a debate for several months with a couple of shooters about shot strings and whether they actually exist. Is it an advantage to use a really tight choked gun to get a longer shot string working for me?
Tim Jones, Qld
A This is a great question and one that will always raise much debate. It’s a topic that I have a plenty of discussion about.
Shot strings certainly exist. They are caused by the air reacting against the shot after it has left the barrel. This causes some of the shot pellets to move forward faster than others, thus causing a stringing effect. In essence, some of the shot arrives at the target before the rest.
The fact that causes arguments on shooting ranges all over the world is this: if two identical shotshells are used on two different barrels, the tighter choked barrel will produce shorter shot strings than a more open choked barrel. For years I actually thought the opposite: I always assumed the advantage of shooting tighter chokes on distance targets was the myth of the longer ‘cone-type’ effect that these chokes were giving me.
What causes shot stings on tighter chokes to be shorter is that as the wad cup is squeezed through a tighter choked barrel, the leading pellets in the shot column act as a type of windshield for the pellets in the rear of the column. The tighter choke thus keeps the shot column together for longer than a more open choke. The open choke allows the pellets to separate from each other faster; thus, fewer pellets are being protected from each other and therefore, they begin to string faster.
Now that you know all of the technical data, what should you do with it? Firstly, understand that in most cases long shot strings will act as your enemy, not your friend. Deformed or poor shot is the biggest reason for long shot strings, as they are more susceptible to air resistance. Improve your scores by improving the hardness and roundness of your shot. Anything that will benefit your shot column leaving the barrel without large percentages of erratically behaving shot will improve the patterning of your gun with any choke size.
I have to qualify the above comment, as I mentioned in most cases a long shot string will damage your effective pattern. In events such as American Skeet, where shots are taken at very close ranges and smaller No. 9 shot is used, there are plenty of compelling arguments why a longer shot string can be more effective, as the holes in the cone effect of the string are filled with the extra shot that a No. 9 provides. Also, because the shots are taken at such small distances, the patterns do not have enough time to be greatly damaged.
On topics such as this, where fact and fiction are hard to separate, I like to backup my views with some creditable sources. In the 1960s, two great books were written by Edward Lowry, one of the leading ballistics technicians who worked for Winchester Western in the US. Exterior Ballistics of Small Arms Projectiles (1965) and Interior Ballistics (1968) showed some extraordinary photographs of how shot strings behave when shot through cylinder barrels and then full-choke barrels. The high-speed photographs proved that after the shot had travelled just more than 5.5m from the barrel, the cylinder choke already had a greater tail or cone than a full-choke shot charge. This largely cleared up the debate that many had waged for over a century.
An easier book to read, which is nowhere near as technical, is Shotgunning: The Art and Science (1977) by another American, Bob Brister. Brister proves the existence of shot strings by getting his wife to tow a large trailer with very long pattern sheets attached to plyboard on the back. She drives across in front of him at 90 degrees at different speeds and distances as he shoots a stationary shotgun at a target on the leading edge of the sheet and then measures the distance horizontally from the first to the last shot pellet on the pattern sheet. Interestingly, in Brister’s book, he states there was little evidence of shot strings with high-quality No. 7.5 shot in 1.125oz target loads, but quite long strings in soft shot duck loads.