Airsoft Guns: 6 Things To Know Before You Buy

Getting into airsoft guns is harder than it should be, and the reason is that nothing you buy works on its own. Your gun’s velocity only means something once you know the BB weight it was measured with. Your BB weight only matters against your field’s velocity or energy limit. And how your field measures that limit may depend on the gun and power system you are using. Add eye protection and face protection, which are governed by two different standards, and you have six purchases that all reference each other. This guide explains the system so the individual decisions get easy, then points you to the detailed guides for each piece.

If you read one thing

Buy proper eye protection first, before the gun. Airsoft has its own eye protection standard written specifically for 6mm projectiles, and general safety glasses are not the same thing for player-versus-player play.

Eye injuries are the one risk in this sport where the consequences can be permanent. Everything else on this page is a preference. This part is not.

On this page

What Airsoft Actually Is
The Velocity System
Power Systems
The Two Protection Standards
What a First Setup Costs
How Field Rules Work
Where to Go Next
FAQ

How we approach this

This guide draws on published ASTM standards documentation, manufacturer specifications, field rulebooks, and consistent patterns across airsoft community discussion and independent reviews.

We haven’t chronographed or impact-tested equipment ourselves. Where a specification comes from a manufacturer, we say so. Where field practice varies, we say that too — because on nearly every question in this sport, the answer that actually governs is the one printed in your local field’s rulebook.

What Airsoft Actually Is

Airsoft guns fire 6mm plastic BBs at velocities intended for people to shoot at each other while wearing protective equipment. That last part is the whole design brief, and it is what separates airsoft from the two categories it gets confused with constantly.

Category	Projectile	Shot at people?
Airsoft	6mm plastic BB	Yes, with protective gear at designated venues
BB guns	4.5mm steel BB, also called .177	No — target shooting only
Gel blasters	Water-based gel sphere	Varies; generally lower energy

The BB gun confusion is the expensive one, because the guns look nearly identical in photos and the listings use overlapping language. Do not put 4.5mm steel BBs into an airsoft gun — the ammunition is a different size and material, and the two systems are not interchangeable. Steel BBs also cause real injury when fired at a person, which is why BB guns are target equipment rather than player-versus-player equipment.

If a listing says 4.5mm, .177 caliber, or zinc-plated, it is not airsoft. Our BB gun guide covers that side of the line, and it is worth a look if you are not certain which one you actually want.

The Velocity System

This is the part that makes airsoft feel complicated, and it is genuinely the most useful thing to understand before you spend money.

FPS is not a fixed property of a gun

Feet per second measures how fast a BB leaves the barrel. Every airsoft gun is advertised with an FPS figure, and beginners shop on that number as though it were a specification like horsepower.

It is not, because FPS depends on the weight of the BB. Kinetic energy is one half of mass times velocity squared, so at a roughly fixed energy output, a heavier projectile moves slower. The same gun reads a different number on 0.20g than it does on 0.30g.

This is why published velocity figures are traditionally quoted with 0.20g BBs unless another weight is specified — everyone needs a common reference. It is also why an FPS number without a stated BB weight tells you almost nothing.

Which is why joules enter the conversation

Joules measure kinetic energy rather than velocity alone, which lets a field account for both BB weight and speed in a single number. Two guns can both chronograph at 350 FPS and produce different energy if they are shooting different ammunition.

How a field handles this varies. Some publish FPS limits tied to a specified BB weight, which keeps everyone on the same yardstick. Others regulate in joules. Some use different chronograph procedures for different gun types, particularly gas and HPA systems where joule creep is a concern.

Joule creep, and why it matters

Gas and air-powered systems can behave differently from a simple conversion chart. A heavier BB spends longer in the barrel, which can let the system keep transferring energy to it, so the gun produces more energy on heavy BBs than the chart predicts.

The practical consequence: a gas gun that passes chronograph on a house 0.20g BB may be shooting hotter than expected on the 0.30g you actually play with. That is one reason some fields require gas and HPA users to chronograph with the BB weight they actually intend to use.

And gas guns move with the weather on top of all that

An electric gun’s spring produces roughly the same energy across a season. A gas gun’s power source is temperature-dependent by nature, because gas pressure rises with heat and falls with cold.

Green gas loses pressure noticeably as temperatures drop, which shows up as weak cycling and shortened range. CO2 holds up considerably better in the cold. Temperature can also change the output of gas-powered guns in the other direction, which matters when your setup is close to a field’s energy or velocity limit.

Put together, that is the whole velocity picture: your gun’s number depends on the BB weight, the ammunition you actually play with may not match what you chronographed on, and if you shoot gas, the weather moves the number too. Our airsoft BBs guide covers the ammunition half in detail, including what each weight does to trajectory and accuracy.

Power Systems

How a gun launches the BB determines its cost, its upkeep, its cold-weather behavior, and whether it is a toy or a piece of sporting equipment.

System	Found In	Best For	The Catch
Spring	Rifles and pistols	Backyard, bolt-action snipers	Cock before every shot
AEG	Rifles, some pistols	Field play, most players	Battery care, gearbox wear
Green gas	Mostly pistols, some rifles	Realism, gentler operation	Loses pressure in the cold
CO2	Mostly pistols	Cold weather, stronger cycling	More stress on the gun
HPA	Rifles	Experienced, performance-focused players	Tank, rig, and real money

For most first-time field players, an AEG is the default recommendation and the easiest place to start. Electric rifles are simple to run, widely supported, comparatively consistent across normal playing conditions, and backed by an enormous parts and upgrade ecosystem.

For a sidearm, the decision is CO2 versus green gas, and it comes down to climate more than anything on the spec sheet. Green gas is gentler on the gun and cheaper to run. CO2 works better when it is cold.

For beginners, spring power makes the most sense in two places: inexpensive backyard shooting, and bolt-action sniper rifles, where manual cycling is part of the design rather than a limitation.

The Two Protection Standards

Almost nobody explains this, and it is why so many people buy the wrong protective gear twice.

There are two separate ASTM standards covering two separate jobs. ASTM F2879 is the Standard Specification for Eye Protective Devices for Airsoft Sports. ASTM F3398 is the Standard Specification for Face and Ear Protective Devices for Air Soft Sports. Two documents, two different pieces of gear.

The clearest statement of why comes from inside F2879 itself: devices meeting its requirements protect the eyes and the surrounding tissue, and not necessarily any other part of the head. That is the standard telling you, in its own text, that your goggles were never designed to cover your teeth.

What this means when you shop

Eye protection and face protection are two purchases. A goggle sold against F2879 does not cover your mouth and jaw. A lower-face mask does not protect your eyes. Some full-face designs address both in one product, and some fields require both regardless of how you get there.

One practical caution: most consumer airsoft eye protection is marketed on general safety ratings and never mentions the airsoft standard at all. That does not mean a product is poorly made — it means the standard is not doing any work for you as a buyer, so your field’s rulebook has to.

A third standard shows up constantly in this conversation: ASTM F1776, which covers paintball eye, face, and head protection. Paintball gear crosses into airsoft more successfully than equipment from any other sport. Compliant paintball masks are also used for airsoft and are accepted by some fields, but a paintball-style appearance is not a certification — check the actual product and your field’s rules.

Our airsoft goggles guide covers what the eye standard says and how to verify a listing before you trust it. Our airsoft face mask guide covers the other half, including the important difference between mesh over the lower face and mesh over the eyes.

The one product worth buying before anything else

If you want one recommendation from this page rather than a category to research, make it eye protection, and make it something that names the airsoft standard rather than a general safety rating.

The Pyramex I-Force is the pick from our goggles guide for one specific reason: its listing names ASTM F2879 by edition, which almost nothing else in the consumer category does. The dual-pane lens construction also fights fogging structurally rather than relying only on a coating, and fogging is a safety problem rather than an annoyance — people lift their goggles to wipe them, and that is when eyes get hit.

Note that the airsoft standard claim is stated as applying when the strap is worn rather than the quick-release temples. That is a real specification detail rather than a weasel, and the practical instruction is simply to wear the strap. As always, confirm your field’s requirements before relying on any product.

Check the Pyramex I-Force on Amazon →

A sensible first field setup

Primary: An AEG rifle.

Eye protection: Full-seal protection accepted by your field.

Face protection: Lower-face protection if your field requires it, or if you want dental protection regardless.

BBs: Quality 0.25g as a starting point, then tune the weight to your gun.

Power: Battery and an appropriate charger.

Extras: One or two spare magazines.

Skip the pistol at first. A sidearm is useful later, but for most beginners it adds cost before it adds much capability. The same goes for plate carriers, helmets, and optics — that money does more work in a better rifle, better eye protection, and more magazines.

What a First Setup Costs

A gun by itself is not a complete purchase, and this is where beginners get surprised. Here is everything you actually need before you can play, in the order we would buy it.

The buying order

1. Eye protection. Before the gun. If the budget only stretches to one good thing right now, this is it.

2. The gun. An AEG for field play, spring for a backyard, gas pistol if a sidearm is what you want.

3. BBs. Quality 0.25g BBs are a sensible starting point for many field guns, but the useful weight depends on the gun and its hop-up. Cheap or poorly made BBs are not worth the savings.

4. Battery and charger, if you bought an AEG. Gas or CO2 if you bought a gas gun.

5. Face protection. Requirements vary by field and age; lower-face protection is commonly required for younger players and is worth wearing regardless.

6. Spare magazines. The thing everyone underestimates, particularly on gas pistols where magazines contain the gas system.

Bundle sets can make the total cost visible up front, but evaluate the accessories individually rather than assuming they are equivalent to what you would choose separately. Pay particular attention to the eye protection: verify its rating and your field’s requirements before trusting it for play.

Two costs that surprise people. Magazines are the real ongoing expense, especially for gas pistols, where a magazine holds the entire gas system rather than just BBs. And gas or CO2 is a consumable you will keep buying, in a way that an AEG battery is not.

How Field Rules Work

Everything above is background. The rules that actually govern are the ones printed by the venue where you play, and they vary more than any other aspect of this sport.

What a rulebook typically covers:

Velocity or energy limits, usually different for different gun types. Close-quarters play tends to be held tighter than outdoor. Sidearms are frequently held tighter than primaries, because there is no minimum engagement distance to pair them with. Bolt-action snipers often get a higher allowance paired with a minimum distance you have to respect.

Eye protection requirements, which commonly specify full-seal designs and may specify a named standard. Some fields prohibit mesh eye protection outright; others permit it only with rated glasses underneath.

Face protection requirements, which vary by venue and are often stricter for younger players.

Chronograph procedure — whether they measure in FPS with a specified BB weight or in joules with your own ammunition, which determines what you need to bring and what you should test at home.

Biodegradable BB requirements, increasingly common at outdoor fields.

Five minutes that saves a purchase

Read your field’s rulebook before you buy anything. It is almost always posted online, and it is specific about protection and velocity in a way it is not about anything else.

The most common expensive mistake in airsoft is buying a gun that is over the limit, or protection that gets turned away at check-in. Both are entirely preventable.

Where to Go Next

Each of these covers one piece of the system in detail.

Airsoft Rifles

Ten rifles across every power system, plus how gearbox versions affect service and upgrades. Start here if you need a primary.

Airsoft Pistols

Nine pistols across CO2, gas, and spring, and why your sidearm reads a different number in July than in November.

Airsoft Goggles

What ASTM F2879 actually says, why “ANSI Z87” is not the whole answer, and how to verify a listing.

Airsoft Face Masks

Lower-half, full-face, and mesh compared, plus what F3398 covers and why it is a separate purchase.

Airsoft BBs

Every common weight from 0.20g to 0.30g, what each does to trajectory, and how weight changes your chronograph reading.

BB Guns

The 4.5mm steel side of the line, and why the two categories are not interchangeable in either direction.

Frequently Asked Questions

What are airsoft guns?

Replica guns that fire 6mm plastic BBs, designed for player-versus-player games where everyone wears protective equipment. They are distinct from BB guns, which fire 4.5mm steel projectiles and should never be pointed at a person, and from gel blasters, which fire water-based gel spheres.

What do I need to start playing airsoft?

Eye protection that meets your field’s requirements, a gun, BBs, and a power source for the gun — a battery and charger for an electric gun, or gas and cartridges for a gas gun. Face protection requirements vary by venue and are often stricter for younger players, so check your field’s rulebook. Spare magazines come next, and they matter more than people expect.

What FPS do I need for airsoft?

There isn’t one correct FPS. Your gun needs to pass the limit for its class at the field where you play, and the field may regulate in FPS, joules, or both. Limits can differ for close-quarters guns, general-purpose rifles, sidearms, DMRs, and bolt-action snipers, sometimes with minimum engagement distances attached. Check the rulebook before buying the gun.

Why do fields measure in joules instead of FPS?

Because FPS depends on BB weight. Joules measure kinetic energy rather than velocity alone, which lets a venue account for both weight and speed in a single number. Two guns reading the same FPS can produce different energy if they are shooting different ammunition, which is why some fields regulate in joules and specify the BB used at the chronograph.

What is joule creep?

Gas and air-powered guns producing more energy with heavier BBs than a standard conversion chart predicts, because the heavier BB spends longer in the barrel and the system keeps transferring energy to it. The practical result is that a gas gun passing chronograph on a light BB may be shooting hotter on the ammunition you actually play with, which is one reason some fields chronograph gas guns with the player’s own BBs.

Is airsoft dangerous?

The one risk where consequences can be permanent is eye injury, which is why fields require eye protection for everyone in the area rather than just players. Beyond that, hits sting and can leave welts on bare skin, and face and dental injuries are possible without lower-face protection. All of these are substantially reduced by appropriate gear and field discipline.

Can I use airsoft to train for real firearms?

For some things. Licensed replicas with matching dimensions let you practice draw, presentation, grip, and manipulations inexpensively. What airsoft cannot reproduce is real recoil, muzzle blast, or trigger characteristics. Treat it as a supplement for handling repetitions rather than a substitute for live fire.

Is airsoft legal where I live?

Generally yes, but rules vary. Federal law imposes marking requirements on covered imitation firearms when manufactured, shipped, or entered into commerce, commonly through blaze-orange muzzle markings. State and local rules may go further, including on transport and where guns may be used. Verify local law before altering markings or carrying an airsoft replica in public.

How much does it cost to get into airsoft?

The gun is rarely the whole cost. Budget for eye protection, BBs, a battery and charger or gas, and at least one spare magazine on top of whatever the gun costs. Bundle sets make the total visible up front, though the accessories are worth evaluating individually rather than assuming they match what you would pick separately.

What is the difference between airsoft and BB guns?

Airsoft fires 6mm plastic at velocities designed for shooting at people wearing protective gear. BB guns fire 4.5mm steel, also called .177 caliber, which causes real injury and is intended for target shooting only. They look similar in listings and photographs and are completely different products — check the projectile size and material before buying either.

The Bottom Line

Airsoft looks complicated because the pieces reference each other. Once you see the system, the individual decisions get simple.

Your gun’s velocity means something only alongside a BB weight. Your BB weight means something only against your field’s velocity or energy limit, and the way that limit is measured varies by venue and sometimes by gun type. And your protection comes in two parts governed by two standards.

Which produces three rules that cover almost everything:

Read your field’s rulebook before you buy anything. It overrides every product claim and every number in this guide.

Buy the eye protection first. It is the cheapest thing on the list and the only one where a mistake cannot be undone.

Know what your gun does with the BBs you actually play with, and follow your field’s chronograph procedure. Especially if you shoot gas.

Everything else is preference, and the guides linked above will help you sort out which preferences are yours.

Authority reference: the standards referenced throughout our airsoft guides — ASTM F2879 for eye protection, ASTM F3398 for face and ear protection, and ASTM F1776 for paintball eye, face, and head protection — are published by ASTM International and listed in their sports and recreation standards catalog. Standards are periodically revised; check for current editions.