Weapons & Marksmanship Fundamentals Core

Shotgun Fundamentals

Lesson 24 of 60 · Module 4, lesson 3

Your objective

By the end, you'll be able to explain shotgun gauge, distinguish shot from slug, describe how choke shapes a pattern, and decide when a shotgun is the right tool.

Concept ~8 min

A dove rockets across the field, juking on the wind. You’ll never thread one rifle bullet through that — but a fistful of pellets opening into a pattern? Now you’ve got a chance. The shotgun is built for exactly this moment. Learn how it works and you’ll know when to reach for it.

Quick recall

Quick recall from Firearm Types Overview — a shotgun fires which of these?

A payload of many pellets (shot) — or a single slug Only one spin-stabilized bullet, like a rifle A front-loaded powder charge and ball

Show answer

Correct: A payload of many pellets (shot) — or a single slug — Right. Shot spreads into a pattern for moving targets up close; a slug is the shotgun's single-projectile load for deer-sized game.
Not quite: Only one spin-stabilized bullet, like a rifle — That's a rifle. A shotgun's signature load is many pellets that spread — though it CAN fire a single slug too.
Not quite: A front-loaded powder charge and ball — That's a muzzleloader. A shotgun loads a self-contained shotshell and typically fires a spreading pellet payload.

Gauge: a backwards number

A shotgun’s size is its gauge, and the system is counterintuitive: gauge is the number of equal lead balls that fit the bore you can make from one pound of lead. So a 12-gauge bore equals one of twelve lead balls per pound; a 20-gauge, one of twenty. Fewer, bigger balls means a bigger bore — so:

The smaller the gauge number, the larger the bore. A 12-gauge is bigger than a 20-gauge.

Common hunting gauges, biggest to smallest bore: 12, 16, 20, 28, then the .410. The .410 breaks the rule — it’s named for its bore diameter in inches (0.410 in.), not a gauge (NSSF — Shotgun Basics).

12-gauge — the do-everything standard: enough payload for most game, with more recoil than the 20.
20-gauge — lighter, less recoil; a great pick for new and smaller-framed hunters and for upland birds.
28-gauge / .410 — light and low-recoil, but small payloads; better for small game and experienced wingshooters than for a beginner’s all-arounder.

Deep dive Why shotshells also come in lengths (2¾, 3, 3½ in.)

Beyond gauge, shells come in lengths — 2¾, 3, and 3½ inches — measured as the hull length before it’s loaded and crimped. A longer shell holds more shot or powder (more payload, more recoil). Critically, a shell must match what the gun is chambered for: a 3-inch gun fires 2¾- or 3-inch shells, but never feed a 3-inch shell into a gun marked 2¾ inch. Check the barrel stamp.

Shot vs. slug — two completely different jobs

The same shotgun can fire two very different loads:

Shot (shotshell) — a payload of many small pellets that spread into a pattern as they fly. The spread is forgiving on small, fast, moving targets: birds on the wing, squirrels, rabbits. Bigger, fewer pellets (buckshot) hit harder for larger game up close.
Slug — a single solid projectile. A slug turns the shotgun into a short-range single-bullet gun for deer-sized game, used heavily by deer hunters, especially where rifles aren’t the chosen or legal method (NSSF — Shotgun Basics).

Schematic from a shotgun muzzle on the left: the upper path shows many small pellets fanning outward into a widening cone labeled as a shot pattern; the lower path shows one large solid slug traveling in a straight line; at right, two cones compare a tight Full-choke pattern with a wide Cylinder pattern. — Diagram (not a photo). Same gun, two loads: SHOT spreads into a pattern (top); a SLUG flies as one solid projectile (bottom). Choke (right) tightens or opens the shot pattern.

Choke: the muzzle that shapes the pattern

A choke is a constriction at the muzzle that controls how fast the shot spreads. Think of your hand: a tight fist opening slowly stays bunched; an open hand spreads fast. Tighter choke holds the pattern together for longer, denser hits at distance; more open choke spreads it wide and fast for closer targets (NSSF — Shotgun Basics).

From most open to tightest, the common chokes are:

Cylinder — no constriction; widest, shortest pattern.
Improved Cylinder — slightly tighter; close-range upland and small game.
Modified — a versatile middle ground.
Full — tightest; densest pattern at longer ranges.

More constriction is not “better” — it’s a tradeoff. A wide-open pattern is forgiving up close but thins out far away; a tight pattern reaches farther but demands more precise aim up close.

Edge case Why a slug usually wants an open choke, not a tight one

Choke is about shaping a pattern of pellets. A single slug doesn’t spread, so squeezing it through a tight Full choke can be counterproductive — standard slugs are generally shot through a Cylinder or Improved Cylinder choke, and many slug guns use a dedicated rifled barrel to spin and stabilize the slug for accuracy. Always check your gun’s and slug’s requirements; never force a load through the wrong choke.

Patterning: confirm, don’t assume

You never assume where your shot goes — you pattern the gun. Patterning means firing at a large sheet of paper at hunting distance (traditionally the pellets inside a 30-inch circle at 40 yards) and looking at the actual result: is the pattern dense and even, or full of gaps a bird could slip through? It tells you your real effective range with that gun, choke, and load — your homework before the season, not a guess in the field (NSSF — Shotgun Basics).

Choose the shotgun setup

A friend hands you their 12-gauge and asks how to set it up for two different hunts. Make the calls.

Decision

Hunt one: doves crossing fast at 20–30 yards. What load and choke?

Birdshot, with an open-ish choke (Improved Cylinder)

Right. Small fast birds up close want a spreading pattern of light shot — the open choke gives you a forgiving pattern for a juking target.

A slug, for more reach

A single slug at a small, fast, crossing bird is a near-impossible — and unsafe — shot. Birds on the wing are shot-pattern work, not slug work.

Check your understanding

Knowledge check

Which has the LARGER bore: a 12-gauge or a 20-gauge?

The 12-gauge — smaller gauge number means bigger bore The 20-gauge — bigger number means bigger bore

Show answer

Correct: The 12-gauge — smaller gauge number means bigger bore — Correct. Gauge runs backwards: fewer balls per pound (12) means a bigger bore than 20. The 12-gauge is the larger bore.
Not quite: The 20-gauge — bigger number means bigger bore — It feels logical, but gauge is backwards. The smaller number (12) is the bigger bore. The 20-gauge is smaller.

Knowledge check

You tighten from Cylinder to Full choke. What happens to your shot pattern?

It gets tighter and denser, reaching farther It spreads wider and faster Nothing — choke only matters for slugs

Show answer

Correct: It gets tighter and denser, reaching farther — Yes. More constriction holds the pattern together longer — tighter and denser at distance, but less forgiving up close.
Not quite: It spreads wider and faster — That's the opposite — the OPEN Cylinder spreads fast. Tightening to Full narrows and densifies the pattern for more reach.
Not quite: Nothing — choke only matters for slugs — Choke is mainly about shaping the PELLET pattern. A tighter choke makes the shot pattern narrower and denser; a slug usually wants a more open choke.

Take it to the woods

Pattern your shotgun before the season — it’s the single highest-value hour you’ll spend with it. The list persists; tick it at the range.

Pattern your shotgun

0/6

Chose the exact load (shot size or slug) I'll actually hunt with.
Set the choke that fits the hunt (open for close birds, tighter for reach).
Shot at a large paper sheet at my realistic hunting distance and looked at the actual pattern.
Checked the pattern for gaps and for where it actually centers.
Set an honest maximum range based on what the pattern (or slug group) shows — not a guess.
Safety Ran the whole session with the muzzle in a safe direction and finger off the trigger until on target.

Sources

NSSF (National Shooting Sports Foundation) — Shotgun Basics (gauge, shot/payload, slugs, patterning analogy). https://www.letsgoshooting.org/resources/articles/types_of_shooting/shotguns/
Hunter-Ed (IHEA-USA aligned) — Common Actions on Rifles and Shotguns. https://www.hunter-ed.com/national/studyGuide/Common-Actions-on-Rifles-and-Shotguns/201099_92829/
SCDNR — SC Hunting and Fishing Laws and Regulations (verify legal loads/methods for your game and zone). https://www.dnr.sc.gov/regulations.html

If you remember nothing else

Gauge is backwards: the SMALLER the gauge number, the BIGGER the bore. 12-gauge is bigger than 20-gauge. The .410 is the odd one out — it's a bore diameter, not a gauge.
Shot is a payload of many pellets that spread into a pattern (birds, small game). A slug is a single solid projectile for deer-sized game up close.
Choke is the constriction at the muzzle: tighter choke = tighter, longer pattern; more open choke = wider, shorter pattern.
Patterning means shooting your gun at paper to SEE your actual pattern at hunting distance — you never assume it, you confirm it.
The shotgun is the short-range tool: moving birds and small game with shot, and deer with slugs/buckshot where that's the chosen or legal method.

How ready do you feel?

How ready are you to explain gauge, shot vs. slug, and choke to a new hunter, and to decide when a shotgun is the right tool for a hunt?

Before you go — a quick look back

Distributed practice: one fast recall from an earlier lesson keeps it from fading.

Quick recall

From Firearm Types Overview — what is the key physical difference between a shotgun's barrel and a rifle's barrel, and how does that shape what each is for?

Show me the answer

Show answer

Correct: Show me the answer — A standard shotgun barrel is smooth inside (smoothbore), so its shot spreads — making it a short-range tool for moving targets. A rifle's barrel is rifled (grooved), spinning one bullet for accuracy at distance. Smooth-and-spreading vs. grooved-and-precise.

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