Firearms 101
Your Complete Beginner's Guide to Firearms
Whether you're considering your first firearm purchase or just want to understand more about firearms in general, this guide is for you. No judgment, no pressure — just clear information.
Types of Firearms
Every firearm falls into one of a few broad categories. Understanding these categories is the first step to making sense of the firearms world.
Semi-Automatic Pistols
The most popular type of handgun sold today
Fires one round each time you pull the trigger, then automatically loads the next round from a detachable magazine. Think of it like a Pez dispenser — each trigger pull delivers one round and stages the next.
Good to know:
- Capacity: typically 7–17+ rounds
- Fast and easy reloading with detachable magazines
- Wide variety of sizes from micro to full-frame
- Requires learning to clear malfunctions
Revolvers
The classic “wheel gun” — simple and reliable
Uses a rotating cylinder with 5–8 chambers. Pull the trigger and the cylinder rotates to align a loaded chamber with the barrel. Easy to see if it's loaded — just look at the cylinder.
Action types:
- Single-Action (SA): Must cock hammer manually before each shot
- Double-Action (DA): Trigger cocks and releases the hammer
- DAO: Every pull is double-action; cannot manually cock
Rifles
Long guns with rifled barrels for accuracy at distance
Rifles have spiral grooves (rifling) inside the barrel that spin the bullet for accuracy. They come in several action types, each with different strengths.
Bolt-Action
Manually cycle a bolt handle between shots. Unparalleled accuracy — the precision shooter's choice.
Semi-Automatic (AR-15)
One trigger pull, one shot, auto-loads the next. “AR” stands for ArmaLite Rifle, not “Assault Rifle.” Highly modular — often called “LEGOs for adults.”
Lever-Action
Cycle a lever under the trigger guard to load the next round. Iconic design, faster than bolt-action.
Shotguns
Versatile long guns that fire shells containing multiple projectiles or a single slug
Pump-Action
Slide the forend back and forward to eject and load. Extremely reliable — works in almost any condition. The most affordable shotgun type.
Semi-Automatic
Fires and auto-loads using gas or recoil energy. Significantly reduced felt recoil compared to pump.
Break-Action
Hinges open to load 1–2 shells. The simplest firearm action that exists — excellent for learning fundamentals.
How Each Action Type Works
Understanding how your firearm cycles is key to operating it safely and troubleshooting issues. Here's what's actually happening inside.
Blowback Operation (Simple Semi-Auto)
The simplest semi-auto mechanism. When the cartridge fires, the expanding gases push the bullet forward and the slide backward. The slide's weight and a recoil spring keep it in place just long enough for the bullet to exit the barrel.
Short-Recoil Operation (Most Modern Pistols)
The barrel and slide are locked together for a short distance after firing. A cam or link then drops the barrel so it unlocks from the slide. The slide continues rearward to eject the spent case, then the recoil spring pushes it forward to chamber a new round.
Bolt-Action (Manual Rifle)
You are the engine. Lift the bolt handle, pull it back (extracting the spent case), push it forward (chambering a new round from the magazine), and lock it down. Four motions between every shot.
Gas-Operated Semi-Auto (AR-15 and Similar)
When a round fires, some of the expanding gas is tapped from the barrel through a small port and redirected to push the bolt carrier group rearward. This ejects the spent case and chambers a new round. The gas system also absorbs some recoil energy, making the rifle more comfortable to shoot.
Pump-Action (Shotgun)
You provide all the energy. Pulling the forend rearward unlocks and opens the bolt, extracting and ejecting the spent shell. Pushing it forward strips a new shell from the tubular magazine and chambers it. Because it's entirely hand-powered, pump shotguns work with virtually any ammunition and in any condition — making them legendary for reliability.
Caliber & Gauge Guide
Caliber refers to the diameter of the bullet (or bore), expressed in inches (.45) or millimeters (9mm). For shotguns, gauge is used instead — and counterintuitively, smaller gauge numbers mean larger bores.
How gauge works:A 12-gauge bore fits a lead ball weighing 1/12th of a pound. A 20-gauge fits a ball weighing 1/20th of a pound. So 12-gauge is actually larger than 20-gauge. The .410 is the exception — it's measured in inches (caliber), not gauge.
Common Handgun Calibers
| Caliber | Common Use | Recoil | Notes |
|---|---|---|---|
| .22 LR | Training, plinking, small game | Minimal | The best starting caliber. Extremely low cost, nearly zero recoil. Perfect for learning fundamentals. |
| .380 ACP | Concealed carry, self-defense | Light | Popular in compact pistols. Manageable recoil with adequate stopping power. A solid step up from .22 LR. |
| 9mm (9x19 Parabellum) | Self-defense, duty, competition | Moderate | The gold standard. Best balance of capacity, recoil, and effectiveness. Most popular handgun caliber worldwide. |
| .45 ACP | Self-defense, duty | Moderate-Heavy | Classic stopping power. Larger, slower round with more felt recoil. Iconic in the 1911 platform. |
Common Rifle Calibers
| Caliber | Common Use | Notes |
|---|---|---|
| .22 LR | Plinking, small game, training | The most popular rimfire cartridge in the world. Very low recoil and inexpensive - ideal for new shooters learning fundamentals. Not ideal for self-defense but excellent for building skills. |
| 5.56 NATO / .223 Rem | Sport shooting, home defense, varmint | The standard AR-15 caliber. Light recoil for a rifle, high velocity. 5.56 NATO is loaded to higher pressures than .223 - a 5.56 chamber can shoot .223, but not always vice versa. |
| 7.62x39mm | Sport shooting, hunting | The AK-47 cartridge. Heavier bullet than 5.56 with a noticeable arc at distance. Very common and affordable. Platforms include the AK-47 and SKS. |
| .308 Win / 7.62x51mm NATO | Hunting, precision shooting, military/police | A powerful, versatile round used in bolt-action hunting rifles and semi-auto platforms like the AR-10. Effective at long range. Significantly more recoil than 5.56. |
| .30-06 Springfield | Big game hunting, long range | A classic American hunting cartridge with over 100 years of history. Excellent for deer, elk, and bear. More recoil than .308 but superb terminal performance on large game. |
| 6.5 Creedmoor | Precision shooting, hunting | A newer cartridge that has quickly become a favorite for long-range accuracy. Flatter trajectory and less wind drift than .308 with comparable or less recoil. Excellent for deer and competition. |
| .300 Blackout | Home defense, suppressed shooting, hunting | Designed to work in AR-15 platforms with only a barrel swap. Comes in subsonic and supersonic loads - subsonic rounds are exceptionally quiet when suppressed. Popular for short-barrel builds. |
| .22-250 Rem | Varmint, predator hunting | An extremely flat-shooting, high-velocity varmint round. Excellent for coyote and prairie dog at long range. Not suitable for large game due to the small bullet diameter. |
Common Shotgun Gauges
| Gauge | Bore Diameter | Best For |
|---|---|---|
| 12 Gauge | 0.729" | Most versatile: hunting, sport, defense. Widest ammo variety but most recoil. |
| 20 Gauge | 0.615" | Recommended for beginners. Noticeably less recoil than 12-gauge while still effective for most purposes. |
| .410 Bore | 0.410" | Minimal recoil. Great for youth and very small-framed shooters. Limited ammunition variety. |
Military to Civilian History
Many of the firearms you see today have roots in military service. Understanding this history helps explain why certain designs are so popular and widely available.
| Military Designation | Era | Civilian Variant | Notes |
|---|---|---|---|
| M1911 / M1911A1 | 1911 - 1985 | 1911-pattern pistols (many manufacturers) | .45 ACP. One of the most copied designs in history. Over a century of service. |
| M1 Garand | WWII - Korea | Available through CMP | Semi-auto, .30-06. Gen. Patton called it "the greatest battle implement ever devised." |
| M16 / M4 | 1964 - present | AR-15 platform (semi-auto only) | .223/5.56 NATO. Civilian versions lack select-fire (full-auto) capability. |
| M9 (Beretta 92FS) | 1985 - 2017 | Beretta 92FS / 92X | 9mm. Served as the US military sidearm for 32 years. |
| M17 / M18 (SIG P320) | 2017 - present | SIG Sauer P320 | 9mm. Current US military sidearm. Modular striker-fired system. Noted here for historical context. |
Civilian Marksmanship Program (CMP):A federally chartered non-profit that sells surplus military firearms (M1 Garands, M1911A1 pistols) directly to qualified U.S. citizens for marksmanship training — one of the most affordable ways to acquire historic military firearms.
Essential Terminology
Walking into a gun store or taking a class is much less intimidating when you know the language. Here are 30+ terms organized by category.
Firearm Parts
- Action
- The mechanism that loads, fires, and ejects cartridges.
- Barrel
- The metal tube the bullet travels through. Internal spiral grooves (rifling) spin the bullet for accuracy.
- Bore
- The interior of the barrel.
- Chamber
- Where the cartridge sits when ready to fire.
- Slide
- The upper part of a semi-auto pistol that moves back and forth during firing.
- Frame / Receiver
- The main body of the firearm. Legally, this IS "the firearm" with the serial number.
- Magazine
- A detachable container holding cartridges that feeds them into the chamber. NOT a "clip."
- Clip
- A device used to load cartridges INTO a magazine. Using "clip" when you mean "magazine" is a very common mistake.
- Muzzle
- The front end of the barrel where the bullet exits.
- Trigger Guard
- The loop around the trigger preventing accidental contact.
- Stock / Buttstock
- The rear portion of a long gun held against the shoulder.
- Forend / Handguard
- The part of a long gun held by the support hand, forward of the action.
Action & Trigger Types
- Striker-Fired
- An internal spring-loaded striker (no external hammer) fires the round. Consistent trigger pull every shot. Examples: Glock, Walther PDP.
- Single-Action (SA)
- Trigger only releases an already-cocked hammer. Light, crisp pull. Example: 1911.
- Double-Action (DA)
- Trigger cocks AND releases the hammer. Heavier, longer pull.
- DA/SA
- First shot is DA (heavy); subsequent shots are SA (light) as the slide cocks the hammer. Example: Beretta 92.
- DAO
- Every pull is double-action. Consistent but heavy. Cannot manually cock.
- Hammer-Fired
- Uses a visible or internal hammer that strikes a firing pin. Can be SA, DA, or DA/SA.
Safety Mechanisms
- Manual Safety
- An external lever or button you engage/disengage. When on, prevents the trigger from firing.
- Grip Safety
- A lever on the backstrap that must be depressed by gripping the gun naturally. Found on 1911s.
- Trigger Safety
- A small lever within the trigger face that must be pressed as part of the pull. Found on Glocks.
- Firing Pin Block
- An internal safety that blocks the firing pin unless the trigger is pulled. Prevents discharge if dropped.
- Decocker
- A lever that safely lowers a cocked hammer without firing. Found on many DA/SA pistols.
Sighting & Accuracy
- Iron Sights
- The default aiming system: a front post and rear notch you align with your target.
- Red Dot Optic
- An electronic sight projecting a red (or green) dot on a lens for faster target acquisition.
- Scope
- A magnified optic for precision shooting at distance.
- Bore Sighting
- The initial process of roughly aligning sights with the bore. Not a substitute for range zeroing.
- Zeroing
- Adjusting sights so point of aim matches point of impact at a given distance.
- MOA (Minute of Angle)
- An angular measurement roughly equal to 1 inch at 100 yards. Used to describe accuracy.
Carry & Legal Terms
- Concealed Carry
- Carrying a firearm hidden from public view. Laws vary by state.
- Open Carry
- Carrying a firearm visible to the public. Laws vary by state.
- FFL
- Federal Firearms License. Required for businesses to sell firearms commercially.
- NICS
- National Instant Criminal Background Check System. The federal database for background checks.
- Holster
- A device to carry a firearm on the body. Types: IWB (inside waistband), OWB (outside waistband), appendix, shoulder, ankle.
Practice & Training
- Dry Fire
- Pulling the trigger on a verified-clear firearm for practice. Safe for most modern firearms and an excellent free training method.
- Limp-Wristing
- Insufficient grip firmness that can cause a semi-auto to malfunction. The slide needs a firm "wall" to recoil against.
- Short-Stroking
- Incomplete cycling of a pump-action, which can cause a failure to feed. Cycle with authority!
- Stovepipe
- A malfunction where the spent casing gets caught in the ejection port, sticking up like a stovepipe.
- Failure to Feed
- When a new round does not properly chamber. Can be caused by bad ammo, a dirty firearm, or a weak magazine spring.
- Rifling
- Spiral grooves inside the barrel that spin the bullet for stability and accuracy.
Ammunition Basics
Ammunition can seem confusing at first, but it follows a logical system. Here's everything you need to know to buy the right ammo and understand what you're shooting.
Anatomy of a Cartridge
Bullet
The projectile that exits the barrel. This is the only part that flies toward the target.
Casing (Brass)
The metal container holding everything together. Gets ejected after firing.
Powder
The propellant inside the casing. When ignited, expanding gases propel the bullet.
Primer
A small impact-sensitive charge at the base. The firing pin strikes this to ignite the powder.
Bullet Types: FMJ vs JHP
FMJ — Full Metal Jacket
- Bullet fully encased in a harder metal shell
- Passes through targets with less expansion
- Used for: Target practice, range training
- Cost:Less expensive — buy this for practice
- Think of it as:A ball bearing — round, smooth, punches through
JHP — Jacketed Hollow Point
- Has a hollow cavity in the tip that causes it to expand on impact
- Transfers more energy to the target, less over-penetration
- Used for: Self-defense, carry ammunition
- Cost:More expensive — carry this, don't practice with it daily
- Think of it as:A mushroom — it expands on impact to create a wider wound channel
What Does “Grain” Mean?
Grain (abbreviated “gr”) is a unit of weight. 7,000 grains equal 1 pound. When you see “115gr” or “147gr” on a box of 9mm ammo, that's the weight of the bullet itself.
Lighter bullets (e.g., 115gr 9mm) travel faster with a snappier recoil. Heavier bullets(e.g., 147gr 9mm) travel slower but have a smoother, pushing recoil. Both are effective — it's a matter of personal preference.
For beginners, standard-weight ammunition is perfectly fine. You'll develop preferences with experience.
How to Read an Ammo Box Label
A typical box label might read: 9mm Luger · 124gr · FMJ · 50 rounds
9mm Luger
The caliber. Must match your firearm's chamber exactly. "Luger" and "Parabellum" and "NATO" are all 9x19mm.
124gr
The bullet weight in grains. Heavier = slower but more momentum.
FMJ
The bullet type. FMJ for practice, JHP for self-defense.
50 rounds
How many cartridges are in the box.
What about +P and +P+ ammo?These are loaded to higher pressures for more velocity and energy. Only use +P or +P+ ammunition in firearms specifically rated for it — check your owner's manual. For beginners, standard pressure ammo is the way to go.
Ready to Get Hands-On Experience?
Reading is a great start — but nothing replaces hands-on learning with a patient, knowledgeable instructor. Our courses are designed for complete beginners in a welcoming, judgment-free environment.