Listen to any shotgunners, especially clay breakers, and the conversation will invariably turn to chokes, with most of what you hear being stunningly inaccurate. So it’s no wonder most give up trying to understand what they do, or become so bound with it that they spend most of their time chopping and changing, often blaming their choice for bad shooting. However, calibre doesn’t matter since what happens is the same irrespective of bore size. Equally fixed or multi puts you at no disadvantage or advantage either.
It all starts the instant the shot exits the cartridge and passes through the rear forcing cone; this conical section funnels it into the bore; industry standard diameter being .729”. As individual pellets jostle for position the shot column starts to elongate as it moves. The next obstacle is the forward forcing cone that feeds it down into the chokes and from there on towards the target.
The shot then develops into a three – dimensional airborne cone with width, depth and length. The slower pellets or those at the front decelerate due to wind resistance and diminishing energy, whilst those at the back accelerate through them. Where the choke comes into play is in controlling how early on in its flight the diameter or spread comes into play. The wider the choke the earlier maximum, effective pattern forms! Cylinder allows this to form within a few feet of the muzzle, whereas a Full restriction will hold together for up to 40-yards before maximum, efficient spread occurs.
Prove it to yourself
To prove this, use the patterning plate. At a distance of around 30-40 yards using the same cartridges, work your way from one extreme of choke to the other and the various spread widths will become apparent. To describe this imagine 30 people walking side-by-side towards a gate.
Opened wide they should be able to pass through into the next field five or so abreast before reforming their line or spreading out. However at a stile where they have to go one by one by forming a queue, Once again they’ll be able to spread out but this time much farther out into the field. Basically the former is a description of Improved Cylinder, the latter Full choke which is reasonable enough for our purposes.
Choke types include fixed (which are machined into the muzzle at factory) and multis. The latter are removable to allow you to fit what you want and come in a number of options flush – fit (level with the muzzle), or extended (projecting ½ - 1” beyond) with Rhino, Comp-N-Choke, Trulock and Browning’s Diamond Titanium being prime examples.
The most common multi-chokes supplied with any new gun, or those bought aftermarket are outlined in the table below along with the measurement. Dependant on where they were manufactured determines how they are described. Here I’ve itemized British and American categories, the US names now the norm since multi-chokes were their invention!
It’s also possible to add a negative choke that’s technically wider than Cylinder. Similarly, at the opposite end of the scale there’s Extra Full, one of my own personal choices on Double – Rise whilst the slightly in between restrictions of 3/8th and 5/8th, often referred to as a slack and tight half, are becoming increasingly popular with many modern DTL shooters. But all control the spread of shot over varying distances.
For close targets such as Skeet, the choke of that name, Improved Cylinder or ¼ are ideal. For general sporting purposes ¼ and ½ will serve as well as any, whilst ½ and ¾ or ¾ and Full tend to be the traditional for DTL although many of the top boys who still prefer fixed chokes frequently have them eased or opened up to 5/8 and ¾. However, Universal Trench (UT), Automatic Ball Trap (ABT), Double – Rise and Olympic Trap (OT), require ¾ and Full or even Extra Full to ensure the tightness of the pattern is held as long as possible.
Its worth pointing out at that if you have flush-fit chokes, changing to extended ones can make the gun feel different due to the extra weight and its distribution. Steel chokes will promote muzzle heaviness, whereas Titanium will shift the weight back towards you. This needs to be born in mind on a firearm that’s all about instinct and balance…
For those who shoot traditional game guns with fixed chokes, the restrictions tend to be ¼ in the right or bottom barrel and ¾ in the left or top, the order of wide then tight originating from the days of walked – up shooting. Given that driven birds present themselves in the exact opposite way of a fast departing grouse, many shooters either flick the barrel selector and shoot the gun the ‘opposite’ way round or pull the rear trigger first on a double trigger gun! It’s possible to have fixed shotguns converted to multi-chokes, a procedure perfected by Nigel Teague.
An American invention for single – barreled shotguns is the poly choke. This consists of a slotted tube (fingers) and screw collar, the idea being you wind in the collar and it compresses the fingers to create an adjustable restriction. It will go from Cylinder to XX Full but is not as accurate as individually machined tubes. Plus it will add about three inches to the muzzle, but certainly an option for pumps and autos; TruGlo’s ported version is one of the best available.
Down to you
No matter which chokes you fit it’s still down to you. There’s a train of thought that states if you’ve got fixed chokes it removes the decision making process from the shooting equation. Plus cartridge selection can also have a bearing on choke performance, with certain combinations producing more defined patterns than others.
Do also remember that fibrewad loads spread faster or develop their pattern earlier than plaswads once again the choke playing its part. To counteract this some gun manufacturers actually produce barrels specifically suited to whichever wad type you’re using at the time. Here the bores are matched to produce the best obturation (gas seal) so keeping the majority of the gasses behind the load.
Also interesting is choke/cartridge performance. Cartridge-A through a ¼ choke will result in the expected pattern, whilst cartridge-B through the same choke at the same distance will give a ½ choke effect. This can even happen with identical guns fitted with indistinguishable chokes, proof positive that the effort of patterning your gun, chokes and cartridges pays dividends. Alternatively and if you can afford it, you can have your gun and chokes tuned or regulated. Here a gunsmith adjusts every part of the shooting equation namely barrels, restrictions and your chosen ammunition to work in complete harmony even down to the most precise pattern at a set distance.
Two anomalies on chokes are heavy shot sizes such as AAA, BB and buckshot normally used for foxing. Testing shows that too much choke causes the pattern to literally blow apart; here it’s better to go for less restriction which improves it no end. Secondly, steel or non-toxic shot has the effect of tightening the restriction - 1/2 with lead is near Full for steel due to shot size variation and abrasion.
It’s always regarded that the best chokes for your shotgun are those from the manufacturer. The alternative is to opt for one of the aftermarket specialists such as Comp-N-Choke, Rhino or Teague Precision who all produce a variety to fit the well known makes and models. Alternatively, and if you think the outlay is worth it, go to Nigel Teague who can do anything you want.
Also remember; to ensure you order chokes of the correct thread pitch and position or you’ll damage your barrels. Screw in the wrong one and not only will you get it stuck, you’ll also require the services of a gunsmith to remove it and repair the muzzle. For example, not all Browning chokes fit all Browning shotguns, so make sure you know what you are buying!
Also I’d recommend that you keep both choke and bore threads lightly oiled as without this sort of maintenance it’s possible they could stick or even rust in place. Likewise keep the tubes tight as if you shoot with a loose choke it can cause all manner of problems and damage. Manufactures will include a fitting key as standard equipment.
My advice therefore is fit the chokes you think most appropriate or, if they’re fixed, stick with what you’ve got. Then pattern a selection of cartridges, decide on the best and stick with them if at all possible. Whatever you decide, don’t become bound up with chokes to a degree it ruins your shooting and remember; ½ and ½ in both barrels of your sporter will take care of nearly every target you’ll see…
|True Cylinder / Cylinder||0|
|Improved Cylinder / Skeet||5|
|Quarter / Improved Cylinder||10|
|Half / Modified||20|
|Three – Quarter / Improved Modified||30|
|Full / Full||40|
All Prices Are Guides Due to the Changes in US & European Exchange Rates