Shooting myths and misconceptions
Laurie Hart gives the answer to five common queries (and misunderstandings) about guns, ammunition and choke.
1: The tighter the choke the longer the shot string
The exact opposite is true. Apart from deformed pellets (of which more later) the major cause of stringing is air pressure prising the pellets away from each other after they have left the barrel. The onset of this effect is delayed by choke boring, allowing the pellets to remain closely together, as a single ballistic entity, for longer. This delay reduces the amount of flight time that the outer pellets have available in which to lose momentum and fall behind the leading pellets in the pattern. Consequently, the shot column arrives at the target with the minimum amount of stringing. This effect also explains why the average velocity of the pellets from a choke barrel is fractionally higher than from an open bored barrel.
2: A longer shot string makes it easier to hit the target
You can miss in front and the shot will still hit it. The great inequality in speed between the target (be it a game bird or a clay pigeon) and the shot charge makes this assumption invalid. It relies upon the misguided analogy of somehow casting a ‘net' of shot in front of the target into which it then flies. This is completely erroneous, as the speed at which the shot column passes the target is so much greater than the speed of the target. A more realistic analogy would be of trying to catch a thrown ball while crossing its path in a Formula One car at top speed!
Having said all this it is, nevertheless, quite possible to hit the target with tail end of the shot string if the body of the shot cloud has missed the target fractionally in front. The resulting hit is always a poor one, as the pellets towards the rear of the column are the weakest and most widely spread pellets in the pattern. That is why the makers of the best cartridges strive to ensure that their patterns produce the minimum amount of deformed pellets and, consequently, the shortest shot strings. In general, it is better to forget all about shot string and concentrate on hitting the target squarely in the middle of the pattern.
However, there is one aspect that needs to be borne in mind, which is, when shooting very high birds you are likely to lose a significant percentage of the pellets behind the bird (even with a perfectly placed pattern) due to the elongated shot string. At a static pattern test, all these pellets would, of course, appear on the pattern plate. Even though these pellets are, generally, the least effective pellets in the pattern, this factor must be taken into account when assessing long range pattern performance and emphasises the importance of retaining the highest possible pellet count on the pattern plate. Obviously, the effect is greater the more perpendicular the target. Long crossers are affected in the same way.
3: The more open the choke the bigger the pattern
Right, up to the 58” spread of the true cylinder at 40 yards, as given in the Eley Diary. While it is true that the more open the choke the bigger the spread, the actual effective pattern is very much dependant upon the range. For example, at 40 yards a full choke has a far larger effective pattern than a true cylinder. It is incorrect to assume, as many do, that a more open pattern makes it easier to hit the target at all ranges. As it is normally the very long range targets that most people have trouble hitting, they would often do better with more choke rather than less if these targets form a fair proportion of their shooting. Most accomplished Shots are well aware of the limitations of open patterns on long targets. But, if shots below 25 to 30 yards are the norm, then open borings are best.
Most Shots would do well to remember that effective patterns - that is, patterns through which an average game bird or clay pigeon is almost guaranteed to be hit with an adequate amount of pellets, are never much more than around 2 feet in diameter. When the range is extended, or the pattern too open, then wounded birds and chipped clays are the order of the day, unless the target is in the dead centre of the pattern.
It is often pointed out that, at close range, a true cylinder pattern can have a pattern of double the effective size of a full choke. It is rarely ever mentioned that at extended range the roles are reversed! Essentially, it is up to you at what distance you want your largest effective pattern. If you want it at 20 yards, use true cylinder, if you want it at 40 yards use full.
4: Shooting across, and into water enables you to see the shot string
What you actually see is the spread, magnified by the shallow angle of the shot as the pellets enter the water. The bottom pellets in the pattern enter the water first and the shot may travel another 15 or 20 yards until the uppermost pellets hit the water. This delayed entry gives the illusion that the shot column is being graphically displayed; when in fact it is merely a projection of the pattern diameter.
5: Swinging very rapidly can spread the shot across the sky
This is an oft-repeated misconception that has no factual basis whatsoever! To make any appreciable difference to the shot pattern the gun would need to be swung at extremely high speed as the shot column leaves the muzzles. A little simple mathematics demonstrates the impossibility of achieving this effect:
If we assume the average cartridge to have a muzzle velocity of between 1300 to 1500 feet per second and the shot column to be approximately one inch long, to produce even one degree of movement between the emergence of the front of the shot column and the departure of the rear (which would still only extend the pattern by around 2 feet at 40 yards), would require the muzzles to move at something in the region of 600 miles per hour. I know we have some super-human shots out there, but I think this would be beyond even them! I estimate that even the wildest, most uncontrolled swing at a target would be unlikely to exceed a speed of 20 miles per hour at the muzzle.
Would this phenomenon be desirable even if we could achieve it? The answer has to be no, as all we would have achieved is a crudely elongated and uneven pattern, more sparsely populated with pellets than the standard pattern.