
Even if you're new to shooting, you probably know that the list of attachments that people put on their guns is seemingly endless. Some of these attachments are tremendously useful in certain situations, others are little more than novelty items, and still others lie somewhere in between. But how do you know which is which, and how do you decide which attachments you need, if any?
In this guide, we'll review some of the most common firearm attachments and their uses. We'll also offer tips on how to decide which ones are best suited to your needs and how to go about installing them.
Types and Examples of Common Firearm Attachments
An exhaustive list of every firearm attachment ever invented would fill a book (probably several books, actually). Although there are tens of thousands, a fraction of them are much more popular and common than the others, so we'll focus on those here.
Extended and Specialty Magazines

Extended magazines — those which hold more rounds than their factory standard counterparts — are among the most popular accessories for magazine-fed firearms. Nearly all kinds of shooters can benefit from increased ammunition capacity, although there are some situations in which the tradeoffs may not be worth it. For example, if you're carrying concealed and it's important to ensure that your weapon isn't visible to others, a larger (and thus more obvious) magazine may be a dealbreaker.
It's best to buy extended magazines made by the same company who manufactured the gun, if possible. Third-party extended magazines are more likely to have quality control issues, such as weaker springs that may cause feeding problems.
There are other kinds of magazine accessories too, such as dual magazine clamps meant to hold two magazines side by side for much faster reloading. You can even get weighted magazines designed to fall free quickly and easily; these are a favorite among some kinds of competitive shooters.
Optics

Pistol and rifle shooters spend billions of dollars on sights and scopes every year. There are optics for shotguns too, but they're not as popular, probably because shotguns aren't designed for pinpoint accuracy to begin with.
Sighting systems come in many varieties, including regular iron sights, offset sights (those that can be folded down when not in use), glow-in-the-dark sights, red dot sights, traditional scopes and specialty models that combine features from several of these. But no matter what kind of optic you buy, most shooters agree: don't skimp on quality. High-end optics can dramatically improve your shooting, but cheap models may not help at all, and they could even worsen your accuracy. Our guide to choosing between a reflex sight and a holographic sight should help you narrow down your choices.
Slings and Scabbards

If you plan to carry a rifle or shotgun anywhere outside your home, a sling (or perhaps a scabbard) is all but mandatory. Slings are best when you need quick access to your weapon, whereas scabbards are more comfortable for long journeys on foot. Both are great ways to keep control of your weapon when you're not holding it with both hands, which isn't always practical. Slings — especially combat slings — also make it harder for an aggressor to take your weapon away from you.
Grips, Stocks and Foregrips

On long guns, the stock is the part that rests in the pocket of your shoulder when you assume a shooting stance. On all types of guns, the grip is the part you hold with your shooting hand when you're ready to fire. The foregrip, if applicable, is gripped with the other hand to provide additional stability and recoil control.
Popular guns often have dozens of alternate stocks, grips and foregrips to choose from. Because these attachments make it easier to shoot large-caliber guns with confidence, they're especially helpful for shooters who are small or not very muscular.
Lights and Lasers

Most self-defense situations happen at night or in dark areas, so if you carry a handgun for that purpose, it's not a bad idea to also carry a light (whether separately or attached to your firearm). Brighter is better, not only so you can see your target more clearly but also because a sufficiently bright light can itself be a deterrent: it may aid you in resolving the situation without having to shoot anyone. Laser sights can be great as both training aids and as self-defense tools, and our guide on choosing a laser sight will help you find the right one for your weapon.
Barrel Attachments

Accessories that attach to the barrel of your weapon can serve many different purposes. Suppressors make gunshots quieter (although not nearly to the extent we see in movies). Flash hiders reduce or eliminate muzzle flash, making the shooter harder to locate in darkness. Muzzle brakes, so named because they reduce bullet velocity, make recoil easier to manage at the cost of reduced power and increased noise. Ported barrels (those with holes drilled or cut into them) serve a similar purpose. Shotgun chokes reduce the spread of the shot for improved accuracy and range. There are plenty of barrel attachments out there to fit a variety of needs.
Secondary Weapon Underbarrel Attachments

Depending on your needs, it may be helpful to have two different weapons in one. Bayonets are a common example, as is the well-known Masterkey underbarrel 12-gauge shotgun. Both are compatible with most AR-15 rifles. Civilians can't own 40mm explosive grenade launchers, but the 37mm variant is legal because it only launches non-destructive rounds such as flares and smoke grenades. Some secondary weapon systems (including the Masterkey) can be legally owned only with additional ATF paperwork.
Quality of Life (QOL) Improvements
For the purpose of this guide, we define "quality of life" accessories as those which are designed more for comfort and ease of use than for necessity, although they could be considered necessary in certain situations. Common examples include extended slide release levers and flared magazine wells, both of which allow handgun users to reload faster and more easily. Recoil pads are another example: they can reduce the discomfort associated with recoil in large-caliber guns.
Other Accessories
Some attachments may not fit neatly into a specific category. These include items like:
Bipods, which offer rifle shooters additional support and accuracy
Rangefinders to aid in determining the distance to your target
Shell saddles for quick access to extra ammo
Pistol grips can make weapons more compact or more comfortable to hold (usually, it's one or the other)
Hollow buttstocks and foregrips can slightly reduce weapon weight and store small items, such as cleaning kits
How to Choose Attachments for Your Weapons and Needs
It's not hard to get carried away with attachments. Customizing your weapon is fun and exciting, but if you go overboard, you'll end up with a weapon that's too bulky and awkward to use effectively. Two considerations are especially important to keep in mind: essentialism and efficiency. When choosing attachments, ask yourself two questions: "Is this attachment essential, given the role I need this weapon to play?" and "Is there a more efficient way to expand the weapon's capabilities, like by using one attachment that can serve more than one purpose?"
Of course, if you're shopping for attachments purely to make shooting more fun, then you don't have to worry about either of these considerations. Go nuts (just do it safely).
Combat Applicatoins

At the end of the day, guns are designed primarily to kill things. Even guns used exclusively for sport are still deadly weapons and must be treated as such. Guns used by policemen and soldiers are designed specifically to kill other people in open combat, and certain attachments (often referred to as tactical accessories) can make them more effective at that purpose.
Attachments commonly regarded as combat accessories include extended magazines, dual magazine clamps, lights, lasers, shell saddles and certain kinds of optics. In essence, any attachment that enables the shooter to fire more quickly and accurately, or to reload less often, could be a good fit for a combat weapon.
Depending on the shooter's needs, barrel attachments like suppressors and flash hiders may also be good choices, especially if stealth is a priority.
Personal and Home Defense

There's a lot of overlap between combat weapons and those intended for home defense or personal defense, for obvious reasons. Overall weapon size, weight and ease of use are bigger concerns for defensive weapons than they are for combat weapons. Concealability is also a prime concern for self-defense handguns.
For these reasons, we generally recommend choosing only those attachments which are truly essential and which don't make your weapon significantly heavier or bulkier. Glow-in-the-dark sights, ported barrels, flared mag wells and custom grips can all improve the gun's performance while having little or no impact on size and weight. Lights, lasers and light/laser combo units can also be good choices. Before even considering attachments, though, be sure to take a look at our list of the best guns for home defense.
Hunting

Unsurprisingly, the attachments you'll use for hunting are mostly different from those you'd use for law enforcement or personal defense. The first and most important step in choosing hunting attachments is to check with your local Game and Fish Department to see what's legal. Magazine capacity is a common concern; many states limit capacity to about five rounds, so extended magazines are probably out.
Many shotgun hunters use chokes or optics designed for short-range shooting, such as reflex sights. Rifle hunters often choose holographic sights or traditional scopes, both of which are ideal for mid to long-range shooting. You can also use quality-of-life attachments like recoil pads and shell saddles as desired.
If you're interested in hunting but you're just getting started, be sure to look at our hunter safety tips. If you're in the process of planning a trip, our guide to hunting on public land is a must-read, too.
Sport Shooting

It's hard to say much about attachments for sport shooting because they will depend almost entirely on the sport in question. Every sport and league has different rules and requirements. Some shooting clubs emphasize minimalism, requiring members to shoot with specific, unmodified firearms. Others might allow any attachment that police and military shooters might use. Our introductory guide to competitive shooting has some more helpful information for beginners.
Installing Attachments
Different types of attachments require different methods of installation. Most are simple enough that you can install them yourself with even a basic knowledge of firearms, but in some cases, you may need a gunsmith's help.
Rail Systems

Most attachments that use rail systems are quick and easy to install. There are two major types of rail systems: Weaver and Picatinny rails. Weaver rails are the older, less versatile version, and today, they're less common. The two types of rails can look almost identical; the slots on a Picatinny rail are just slightly wider than those on a Weaver rail, but the difference is difficult to see without a side-by-side comparison.
Most rail systems sold today are Picatinny rails, partly because Weaver accessories will fit on a Picatinny rail, but the reverse usually isn't true. The vast majority of Weaver and Picatinny accessories can be installed with no tools or with simple tools such as Allen wrenches.
Scope Mounts

There may be only two main kinds of rail systems, but scope mounts are a different story. Whereas some sights and scopes can be mounted on Weaver or Picatinny rails, many require a different mounting system, and there are dozens of them. Some can be used on any firearm, whereas others are manufactured to fit specific models. The best advice we can offer is to research optics very carefully before buying them. Make sure you know exactly what type of mounting system you'll need and whether that mounting system is compatible with the firearm you have in mind. Assume that the scope or mounting system isn't compatible with your firearm or rail system unless its documentation specifically states that it is.
Sling Mounts and Rings

Like scope mounts, sling mounts can attach to either a rail system or the firearm itself, usually via some sort of clamp in the latter case. The good news is that sling mounts are less likely to be firearm-specific and are typically much less confusing than scope mounts. Even so, be sure to read the documentation before buying to ensure that the mount is compatible with your specific firearm.
Barrel Attachments

Most barrel attachments require a threaded barrel, which is exactly what it sounds like. These attachments simply screw onto the threads on the exterior surface of the muzzle. There are robust first and third-party markets for threaded barrels for many popular guns. Some parts, such as ported barrels, aren't technically attachments; rather, they replace the original barrel entirely, just as a threaded barrel does.
Safety is a prime concern when you're swapping out barrels and using barrel attachments. Using the wrong parts (or installing the right parts incorrectly) could potentially cause catastrophic malfunctions when the gun is fired. If you have any doubts, consult a qualified gunsmith.
Other Installation Methods
Some firearm modifications are simply too complex or dangerous for laymen to attempt. Certain attachments come with warnings that strongly recommend gunsmith installation. But in any case, never hesitate to get professional help if you're unsure about your own ability to install new parts correctly.
Customizing your firearm to make it uniquely yours can be fun and gratifying. Whether you're an up-and-coming 3-gun competitor or simply a parent with a family to protect, there are any number of attachments to choose from that can make your firearms even more effective. As always, be sure to train well and often. Ultimately, your firearm's effectiveness depends on your skills and safety habits.
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