What Are Shotgun Chokes?

Picking the right shotgun choke can seem confusing, but a basic understanding can dramatically improve your bag. Choosing the correct choke depends on several factors – we’re going to break down the basics.

A shotgun choke alters the pattern of shot by constricting it as it leaves the barrel. The most suitable choke depends on the application, yet the use of chokes is not exclusive to any one discipline.

Although today it is most common for guns to support interchangeable chokes (known as multichoke), some shotguns are permanently choked through modifications made directly to the barrel (fixed choke).

Why should you use a shotgun choke?

A shotgun choke modifies how shot leaves the barrel, and therefore how it travels through the air. By picking the right choke, you can increase your chances of hitting a target.

For a close proximity target a wider spread of shot is ideal, whereas at distance a tighter shot pattern is preferable. Close, moving targets require a more rapid response. Furthermore, as the shot doesn’t travel far before reaching the target it is unable to spread out – meaning greater accuracy is required. When shooting close, fast-moving targets you should aim to spread out your shot as much as possible. This is often achieved using a true cylinder choke. A true cylinder choke is the least restrictive of all chokes, and causes shot to behave as though the barrel is not choked. Whilst it may seem excessive to use a choke in this circumstance, shot must not be fired over threads (which would be the case if no choke was used).

At longer distances shot is prone to spread out too much, which can hamper its killing ability. What’s more, in disciplines such as practical shotgun, a broad shot pattern can mean that penalty targets are hit, or that not enough shot hits the intended target to topple it. Where greater precision is required, a restrictive choke is needed. This makes the shot behave less like a bubble, and more like a string.

Generally speaking, greater accuracy is achieved by using the least restrictive choke available, whereas high precision necessitates a tighter choke.

Shotgun choke sizes

Chokes are differentiated by the restriction they provide. A true cylinder is the most open shotgun choke, whereas a full choke has the tightest shot pattern. It is important to note that the names given to restrictions vary geographically – we’ve included a conversion chart below.

Choke size (UK)Choke size (US)% of shot in 30” circle at 40 yds
True cylinderCylinder40%
Improved cylinderSkeet50%
QuarterImproved cylinder55%
HalfModified60%
Three-quartersImproved modified65%
FullFull70%

Whilst choke sizes give relatively consistent results, cartridges can have a notable impact on patterning. Another thing to note is that to produce a similar outcome between calibres, chokes vary in thickness – for example, a half choke on a 12 bore provides 0.020” of restriction, whereas on a .410 the restriction is 0.012”.

US Choke size12 (inches)20 (inches)28 (inches).410 (inches)
Cylinder.000.000.000.000
Skeet.005.005.005.005
Improved cylinder.010.009.009.008
Light modified.015.012.012.010
Modified.020.015.015.012
Full.035.024.024.018
Extra full.040.027.027.020
Diffusion.005 & rifled.005 & rifledN/AN/A
The amount of restriction each size of choke provides

Identifying shotgun chokes

Identifying a choke is different depending on who produced it. Some chokes use notches on their face to indicate their size, whereas others use codes, stars, or even colour bands.

ChokeNotches/starsAlpha codeSerrationsColour bands
Cylinder///// (five)CYL5Blue
Skeetn/aSKn/aRed
Improved cylinder//// (four)IC4Yellow
Modified/// (three)M3Green
Improved modified// (two)IM2Black
Full/ (one)F1Gray

Different types of shotgun choke

Each major gun brand offers several different chokes, each an improvement on its predecessor. In almost all cases chokes are not interchangeable, even within brands – you must use the correct choke type for your barrel.

Beretta chokes

Beretta has gone through four choke iterations, beginning with Mobil-choke. The Mobil-choke was released in the 1980s, and continues to be used on their Field 680 models. By 2000 Beretta had begun to introduce back-boring to their barrels, and needed a choke that could provide proper constriction.

A trend towards heavier shot, and movement away from lead and towards steel necessitated a new generation of chokes that could handle increased forces. This began in 2003 with the Optima-Choke Plus, which was iterated on in 2008 with the release of the Optima-Choke HP – designed to handle even greater forces. Today, all new choked Beretta shotguns use the Optima-Choke HP.

Choke nameBarrel markingRelease dateCalibre(s)
Mobil-ChokeNone~198512, 20, 28, .410 bore
Optima-ChokeOB200012 bore
Optima-Choke Plus3 ½”200312 bore
Optima-Choke HPOB HP200812, 20, 28 bore

Browning & Miroku Chokes

Much like Beretta chokes, Browning chokes have evolved over 30 years to handle increased forces. Browning chokes are also used on Miroku shotguns.

Choke nameBarrel markingRelease dateCalibre(s)
Invector“Invector” or “Standard Invector”Unknown10, 12, 16, 20, 28, .410 bore
Invector Plus“Invector-Plus” or “Invector+”Unknown12, 20 bore
Invector DS“Invector-DS”Unknown12, 16, 20 bore

What’s the difference between extended and flush chokes?

The biggest difference between extended and flush shotgun chokes is aesthetic. Whilst extended chokes essentially extend your barrel by an inch, the real-world benefits of this are minimal.

Which choke is best for practical shotgun?

Whilst it’s easy to focus on the differences between clay pigeon shooting and practical shotgun, similar cartridges are used for both disciplines, so the same basic considerations apply when considering the most appropriate choke.

The most important considerations are distance and pellet count; you want to be able to put enough shot on a target to topple it, and avoid any nearby penalty targets. However, you don’t want to constrict your shot too much as this will require unrealistic precision (particularly at close range). 

Whilst choking your gun might feel like a challenge in and of itself, it’s important to remember that when a course is assessed by a calibrator, all targets must be found to be accessible using standard match ammunition in a cylinder-choked gun, with a barrel no greater in length than 65cm. This is important, as although choking your gun correctly can make things much easier in the heat of the moment, it is not strictly vital that you recognise the benefits of choking to be competitive in practical shotgun.

If you opt to use chokes, make sure that you’re familiar with how your ammunition responds to choking. Choking is not consistent across ammunition – for example, plastic wadded cartridges tend to shoot tighter than a fibre cartridge. If you take shooting seriously you should test your chokes and ammunition using cardboard to assess the way shot behaves at different distances under the given choke and cartridge combination.

Which is the best choke for shooting clays?

The best choke depends on what you’re shooting. For example, compared to Trap, Sporting clays are much closer (typically no further than 30 yards away). In these close-quarter situations it is wise to opt for minimal choking so that the shot has spread out to an appropriate degree by the time it reaches the target. If a too restrictive choke is used, the shot will not have spread out sufficiently.

When shooting Trap, on average targets are around 60 yards away. In these longer distance scenarios tighter choking is ideal, as it helps to hold the shot together (where it would otherwise be prone to spread out to an undesirable degree).

If in doubt, you can opt for a combination of chokes; it is common for shotguns to sport a half and quarter chokes. If you are completely lost, choose less restrictive chokes.

Distance (yds)Distance (m)Choke
40-5035-45Full (full)
35-4030-35Half (modified)
30-3525-30Quarter (improved cylinder)
25-3020-25Improved cylinder (skeet)
Recommended choking

Which is the best choke for shooting game?

Variety amongst the way game is shot means there is no one-size-fits-all answer to this question. However, generally speaking the same distance-related factors outlined under “which is the best choke for sporting clays” apply.

For driven game, such as pheasants it is recommended that three-quarter, half, modified, or full choke is used. For partridge, opt for something more restrictive, such as an improved cylinder (skeet) choke. In all cases, test your choking using your preferred cartridge, and cardboard to assess shot pattern.

If you are unsure about the correct chokes to use, it is best to choose a combination of quarter and half chokes, altering only your cartridges to achieve different spreads.

Can you use a choke with buckshot?

Owing to the way that buckshot is arranged inside of a shotgun cartridge, unlike birdshot, it is not readily rearranged. Therefore, whilst using an appropriate choke with buckshot will reduce the spread of shot, it will not have a drastic effect on patterning.

Although it is safe to use some choking with buckshot, it is not recommended to over restrict your shot, as this will alter the shape of your shot – negatively impacting accuracy – and result in damage to your choke over the longer term.

Before shooting buckshot through chokes, check the guidelines provided by your ammunition manufacturer. This is often available on the packing, otherwise, reach out to them by phone.

Can you use a choke with a shotgun slug?

Unlike when shooting birdshot or buckshot, when using chokes with a shotgun slug there’s less to constrict, and therefore the use of chokes has notably less effect. However, many like to use chokes with shotgun slugs to realise a little more accuracy.

The size of choke to use with a slug varies depending on the specific type of ammunition. However, it is commonly said that an improved cylinder (or skeet) choke is the most appropriate, and it is ill-advised to restrict the slug any further.

Always refer to the documentation supplied with your ammunition before using anything other than a true-cylinder (or cylinder) choke with a shotgun slug. Alternatively, contact the manufacturer directly.

What is backboring?

Backboring is the process of increasing the internal diameter of a barrel with the intention of reducing friction and recoil. Although back boring can be carried out retrospectively, it is now common in new guns.

There is no evidence to suggest that back-boring has a dramatic effect on performance. Whilst reducing friction has benefits, a greater internal bore diameter means that the seal formed between a wad and the barrel is less effective, and therefore energy is lost. Furthermore, recoil is affected by numerous factors, including cartridge and gun, so any reduction in recoil is hard to confirm.

Some shooters find high-quality plastic wads to be effective at minimising the energy lost through poor sealing in a back-bored barrel.

How to fit and remove a shotgun choke

The way a choke is fitted and removed varies depending on its style. Whilst all chokes rely on threads to fix inside of a barrel, some are installed by hand, whereas others require a key.

When fitting a choke, it is crucial that it is firmly secured. If the choke is not properly seated then it may be ripped from your barrel – in the best case damaging your barrel’s threading, and in the worst resulting in serious injury. Never leave a choke loose with the intention of coming back to it later.

Extended chokes are usually designed to be fitted by hand. This is apparent by a lack of notches on the barrel end of the choke, and made possible by it’s extension outside of the barrel.

Shotgun chokes in barrel

Flush chokes require a key to be installed and removed. The key used varies depending on the choke manufacturer – choke keys are not universal. Choke keys are widely available, and can be found at all gun shops or online.

Beretta choke key

Where to buy shotgun chokes

Shotgun chokes are widely available and can be found at any gun shop throughout the world. In many countries chokes are not restricted items, and therefore can be bought and sold online without special provisions.

Providing proper inspection is carried out (including a search for cracks, deformities, etc.), buying second-hand chokes online is a great way to save money. They can be bought readily on sites such as eBay and Facebook Marketplace.

Miscellaneous

Which shotgun choke is the most open?

A true cylinder (or cylinder) choke is the most open shotgun choke, and mimics a barrel without chokes. A true cylinder choke provides the most lead dispersion of all common choke types.

Which shotgun choke has the tightest shot pattern?

A full choke offers the most restriction of all common choke types, and provides the tightest shot pattern.

Are shotgun chokes interchangeable?

Shotgun chokes differ between brands. Whilst Browning and Miroku share the same choke types, Beretta use their own chokes. Because of this, although some shotgun chokes are interchangeable, this is not guaranteed across all brands.

Leave a Reply

Your email address will not be published.