Making sense of choke

David Crofts

It seems that as a whole, shotgun shooters seem overly preoccupied with choke – ‘which choke is best for this clay target and that clay target?’ and ‘which choke is best for shooting long-range ducks?’ are just a couple of the questions that arise on a regular basis. When given a shotgun to examine just wait and see how long it takes for the examiner to enquire as to how the gun is choked or if it’s a multi-choke, what chokes come with it and I don’t believe you’ll be waiting for more than a minute or two before the question is asked.

The most important thing to realise about shotguns is not how the gun is choked in the last two or three inches of the barrel/s but whether the gun ‘fits’ and is balanced to suit your shooting style or technique, though we’re not dealing with fit or balance in this article.

Choke was discovered at roughly the same time by W.R. Pape ‘the inventor of choke’, a gunmaker from Newcastle-upon-Tyne in England and Fred Kimble, a North American who worked as a market gunner during the mid-1860s. However, it’s generally accepted that W.W. Greener developed and perfected choke boring during the early 1870s which led to ‘The Field Trial of 1875 – Cylinder v Choke bore guns’. After the trial, shooters of the day accepted wholeheartedly the superiority of the choke bore guns.

Choke is generally measured in thousands of an inch, sometimes called points, so 40 thou’ of choke could also be described as 40 points of choke (be aware some European gunmakers do use the metric system). It’s generally accepted pattern percentages from the various degrees of choking are as follows*: Cylinder (40 per cent  pattern at 40 yards) no choke; Skeet (50 per cent pattern at 40 yards) – 5 thou’ of choke; Improved Cylinder (55 per cent pattern at 40 yards) – 10 thou’ of choke; Modified (60 per cent  pattern at 40 yards) –  20 thou’ of choke; Improved Modified (65 per cent pattern at 40 yards) – 30 thou’ of choke; Full Choke (70 per cent pattern at 40 yards) 40 thou’ of choke.

* There are numerous variations to the above (regarding choke descriptions, dimensions and performance) due to the many shotgun and aftermarket choke manufacturers. Writer Tom Roster recently noted “shotgun and screw-in choke manufacturers have confused this issue almost beyond understanding by not agreeing to universal choke-dimension standards but then applying consistent names to chokes anyway such as Full, Modified and Improved Cylinder or ¾, ½ and ¼, implying universality”.

Yet just because a barrel is choked to a particular constriction it doesn’t follow the constriction concerned will pattern to the expected percentage associated with it. For example I’ve seen a barrel with an Improved Cylinder boring of 10 thou’ (expected to throw a pattern of 55 per cent within a 30” circle at 40 yards) actually produce patterns on the pattern plate between 50 per cent and 70 per cent by changing nothing more than the type of cartridge being used.

This clearly demonstrates that just because a barrel is choked to a particular constriction there’s a good chance it won’t provide the performance expected by the user and the only way to be sure of this is to pattern your gun on a pattern plate with the cartridge you intend to use. Ask yourself this: How many people with whom you shoot actually pattern their gun or guns with the cartridges they use?

In the sporting press these days it appears there’s a lean towards using a more tightly choked gun for general sporting clay targets and shooting game though I personally believe most shooters actually impede themselves by ‘over-choking’ when shooting sporting clays and gamebirds. This belief was noted by Bruce Bowlen, a former Director of the Orvis Wingshooting Schools: “My experience as an instructor has led me to believe most shooters tend to use too much choke than too little. This is directly related to most folk’s tendency to over-estimate range.”

There’s a case for using Cylinder for shots up to 30 yards. Cylinder is an enigma in that it consistently throws the most even patterns of all the various degrees of choke available and this evenness of pattern is supported by the following two statements: “In the thousands of patterns tested by George G. Oberfell and Charles E. Thompson for their Mysteries of Shotgun Patterns, the point is made repeatedly that the pure-Cylinder choke throws the most even patterns of all,” (Bob Brister). “The Cylinder had a considerable advantage in one way as its pattern was larger and more evenly spread,” (Sir Ralph Payne-Gallwey).

The concept of choke as we know it today arose from the early days in development of the breech-loader when cartridge performance was woefully poor compared with the cartridges available today. The effect of rolled turnover crimps with overshot card wads and propellants of the time (black powder and early smokeless powders such as Schultz) could be vicious on the soft lead pellets as they were forced up the barrel with the wadding then available. You may be surprised to learn most shots are actually taken between 20 and 35 metres from the muzzle, so if most shots at game and targets are taken from 20-35 metres, which is the ‘best’ choke for use within this zone?

Jack O’Connor stated “a gun which will deliver 50 per cent patterns at 40 yards is an exceedingly useful instrument and will do for about 90 per cent of all shooting”. Bob Brister went into a little more detail than O’Connor by saying: “So what we have here is one choke that’s quite deadly for a distance of about 18 yards (from 20 yards to 38 yards with most hunting loads in a 12 gauge) and another (Full) that shines for 10 yards or so with the same ordinary load. Moreover in the Improved Cylinder’s favour, the 18 yards or so where it is best happen to be the very ones where most hunters can, and do, take their game.”

I’m not saying there’s no place for tighter chokes in shooting – it’s ‘common sense’ that if shooting edge-on clay targets (as in the trap disciplines or the longer range FITASC-type sporting targets well above 40m in range) or long-range gamebirds at 40 to 50m – you’ll need tighter chokes to give you the patterns required for efficient kills in shooting targets and game at those distances.

Brister adds: “The Full Choke’s reign of superiority is considerably shorter in useful yards than the Improved Cylinder’s. Between 40 and 50 yards, where the Full Choke shines, even the best of patterns begin to undergo a number of ills inherent to the smoothbore.” So for genuine longer-range shooting the tighter choking does become more advantageous, yet there’s an old saying about choke that “it lengthens your reach but may lighten your bag.” So unless you’re an exceptional shot like Michael Diamond or George Digweed, you may well hinder yourself in most shooting situations by using too much choke.

To break this down to basics, if your clay targets or game are taken at 25m or less (the exception here being trap or trap-type targets) use Cylinder, Skeet or Improved Cylinder chokes. At up to 35m use Improved Cylinder, Light Modified and Modified. If your shots are taken from 35 to 45 metres or more, tighter choke constrictions from Modified through to Full/Extra Full constrictions will be required. After more than 40 years of shooting clay targets and winged/small game with a shotgun I generally lean towards the more open choke borings, dependent upon quarry/target presentation and distance.

No doubt there are plenty of shooters who completely disagree with my ramblings but after a good day’s shooting there’s nothing like having a few drinks with your mates and a debate on what was hit, what was missed and the reasons why – including what’s the best ‘choke’! And if you’re unhappy or have any doubts over your gun/choke and cartridge combination, head to the pattern plate and if satisfied with how they’re performing, leave the pattern plate well alone.

Please note if you conduct your own patterning tests, wear safety glasses at all times when shooting at a steel plate and never, under any circumstances, fire shotshells loaded with steel shot at a steel pattern plate as dangerous ricochets may result.

  • References – Bruce Bowlen: The Orvis Wingshooting Handbook (1985); Bob Brister: Shotgunning, the Art and the Science (1976); W.W. Greener: The gun and its development 9th Edition (1910); Michael McIntosh: Shotguns and Shooting (1995); Jack O’Connor: The Shotgun Book (1965); Oberfell and Thompson: The Mysteries of Shotgun Patterns (1957); Sir Ralph Payne-Gallwey: High Pheasants in Theory and Practice (1913); Tom Roster: Shooting Sportsman Magazine (November/December 2017).
All News