66 calibers, gauges, and the stories behind them.

The smallest common centerfire — historically important and fun to collect, but modern micro .380s do its job far better.

Technically sound but fighting the market's gravity — capacity gains are modest, ammo choices thin, and 9mm's shadow is long.

A pleasant-shooting antique of a cartridge — the classic European pocket-auto round that .380 pocket pistols effectively retired.

A clever idea that shoots harder and louder than its size suggests — the extra round is real, but ammo can be hard to find and never cheap.

Serious blast and muzzle flash from short barrels, but from a lever carbine it turns into a soft-shooting brush gun — the most versatile revolver chambering ever made.

Loud, flashy, and expensive to feed — a genuinely capable cartridge that lost the institutional argument to cheap, improved 9mm.

Cartridge, Caliber .38, Ball, M41 (US aircrew issue)

Gentle from a full-size revolver and still the snub-nose standard — a century-old design that modern +P hollow points keep relevant.

Flat-shooting and soft in a heavy 1911 — a competition and Latin American market classic that mainstream American carry largely passed by.

The pocket-pistol cartridge — easy to carry, but tiny blowback guns give it more snap than the ballistics suggest, and ammo runs pricier than 9mm.

.40 S&W's snappier recoil and the FBI's return to 9mm ended its duty-era dominance, but police trade-in pistols make it one of the best used-gun bargains going.

Genuinely stout recoil that most shooters respect after one cylinder — superb for handgun hunting and bear country, less practical for high-volume range days.

A gentleman's big bore — mild to shoot and accurate, but factory ammo is scarce and priced like the specialty item it has become.

Cartridge, Caliber .45, Ball, M1911

A big, slow push rather than a snap — beloved by 1911 devotees, though 9mm's capacity and cost advantages have made .45 the traditionalist's choice.

The original big-bore sixgun round — soft-shooting in standard trim, and mind the sharp split between cowboy-level loads and the heavy stuff made for Ruger-class guns.

Recoil that ends range sessions early — a legitimate big-game revolver cartridge most owners feed .45 Colt for practice.

.455 Revolver Mk II (British service)

A gentle big-bore from another century — factory ammo exists but is scarce, and unconverted Webleys are the collector's prize.

Pure spectacle — enormous muzzle blast, ammo north of two dollars a round, and a grin on everyone at the range when the Eagle comes out.

An event, not a range gun — ammo runs several dollars a round and the recoil is a bucket-list experience most people check once.

The backcountry carry favorite — real power in a duty-size auto, though many commercial loads are watered down to near-.40 levels, so label-reading matters.

5.7x28mm NATO (standardized 2021)

Almost no recoil, 20-plus round magazines, and a flat trajectory — the trade-offs are pricey ammo and a bullet weight class all its own.

7.62mm TT (Soviet service, TT-33 and PPSh-41)

Flat, fast, and startlingly loud with a fireball to match — a collector's delight whose surplus ammo supply is drying up.

9mm NATO (M882 ball in US service)

The default handgun cartridge of the modern era — cheapest centerfire pistol ammo, mild recoil, and the widest gun selection ever offered in one chambering.

9mm PM (Soviet/Warsaw Pact service pistol cartridge)

The surplus-pistol staple — Makarovs are famously reliable, though the once-cheap imported ammo has gotten pricier as import politics shift.

The varminter's hot rod — spectacular on prairie dogs, hard on barrels, and traditionally twisted too slow for the heavy-bullet games.

A genuinely clever long-range idea whose rough launch and the ARC's rise left it a well-liked also-ran.

The classic first deer rifle — mild, accurate, and honest, provided you feed it the heavier bullets when deer are the job.

O'Connor's flat-shooting classic — still one of the best pronghorn-to-elk cartridges going, even if the 6.8mm bore stayed lonely until recently.

6.8x51mm Common Cartridge (US Army XM7 rifle and XM250 automatic rifle)

The Army's big bet — historically significant already, but for civilians it's early days: limited loads, SIG-centric guns, and a two-tier pressure story worth understanding.

Cartridge, Caliber .30, M1 (US M1 Carbine)

Light, quick, and pure history — the M1 Carbine remains one of the most pleasant-shooting military arms ever issued, even if the cartridge is modest by rifle standards.

Caliber .30 Ball M2 (US service through Korea)

The great American do-it-all — enough gun for anything on the continent, with a recoil level that reminds you it predates shoulder-friendly fashion.

The deer camp heirloom — a 150-yard woods cartridge that keeps filling freezers while fancier numbers come and go.

The suppressed-SBR sweetheart — just keep 300 BLK mags religiously separate from 5.56, because a Blackout round chambered in a 5.56 gun is the classic catastrophic mix-up.

MK 248 / A191 US military sniper loadings

Serious reach and serious shove — a proven elk and long-range cartridge that punishes shooters who skip the recoil pad.

Mk VII ball (British and Commonwealth service)

The Empire's cartridge — a smooth-cycling piece of history that still takes deer and moose every fall wherever Enfields went home with veterans.

8.6x70mm; standard Western extreme-range sniper chambering

The mile-shooter's cartridge — extraordinary reach with ammo at four-plus dollars a round and recoil that makes a muzzle brake standard equipment.

The straight-wall-state solution — cheap, mild, and effective inside 200 yards, which is exactly what those woods hunters need.

A lever-gun answer to the straight-wall rules — young, with a thin ammo shelf, but a natural fit for the deer-woods crowd it was built for.

The safari benchmark for a reason — shootable for its power and utterly proven, though stateside it mostly waits in the safe for the trip of a lifetime.

.45-70 Government (US service, Trapdoor Springfield era)

The big lever thumper — bear-country guides love it, and the three distinct load tiers (Trapdoor, lever, Ruger-strong) are the one thing every owner must actually know.

The straight-wall sledgehammer — decisive on deer and hogs inside 200 yards, with recoil and trajectory that both remind you it's a big pistol bullet moving fast.

12.7x99mm NATO; M33 ball; fired by the M2 Browning machine gun

A hundred-year-old legend that costs several dollars per trigger pull — owning one is as much about the experience and the history as any practical need.

5.45x39mm (7N6 ball, Soviet/Russian service)

Silky-soft recoil even by small-bore standards, but the glory days of seven-cent surplus are gone and supply now runs feast-or-famine.

M193 ball; M855/SS109 5.56 NATO; M855A1 in current US service

Cheap, soft-shooting, and everywhere — the AR-15's cartridge and the modern American default, with the .223/5.56 chamber distinction worth knowing but rarely a problem in practice.

The cartridge that ate the precision market — soft recoil, superb factory match ammo, and yes, the internet jokes are mandatory.

The original long-range AR-15 cartridge — still a bargain deer-and-steel setup, with 6mm ARC as the newer sibling it has to share the room with.

The Creedmoor with its sleeves rolled up — genuine elk-country reach, paid for in barrel life and pricier ammo.

Patron m/94 (Swedish and Norwegian service)

The original 6.5 sweetheart — gentle, accurate, and moose-proven, a hundred years before the Creedmoor made it cool.

The hog hunter's AR cartridge — did its job well, but the ARC generation is quietly writing its retirement papers.

Arguably the best all-around ballistics ever squeezed from the AR-15 envelope — the catch is a modest ammo catalog and Grendel-bolt logistics.

M43 (Soviet service intermediate cartridge)

The AK's cartridge — moderate recoil, rainbow trajectory past 300, and its famous cheapness now hostage to import bans and sanctions.

M80 ball; M118LR long-range; 7.62 NATO standard since 1954

The do-everything .30 — deer to a thousand-yard steel with ammo on every shelf, even as 6.5s eat into its precision-game territory.

Russian service rifle and MG cartridge (Mosin-Nagant through SVD and PKM)

The Mosin's cartridge and a living antique still on active duty — the ten-dollar-crate days are over, but the rifles remain history you can shoot.

The classic Western elk-and-mule-deer magnum — flat, proven, and a bit of a barrel-heater, with recoil in the firm-handshake class.

The quiet professional of deer cartridges — efficient, soft-shooting, and chronically underrated next to flashier neighbors.

7.92x57mm (German sS Patrone; Gewehr 98 and K98k service)

The Mauser's cartridge — European loads show what it really is, while American factory ammo babies it; surplus rifles remain one of collecting's great on-ramps.

Charming and genuinely hard to shoot well — the thin patterns punish sloppy swings, which is why old-timers call it an expert's gun handed to beginners.

The goose-pit heavyweight — throws the biggest payloads going, in guns that weigh like boat anchors and shells priced like a specialty item, because they are.

US military combat and breaching shotguns (M870, M26, Mossberg 590 series)

The one-gun answer — from clays to geese to the bedside, no other chambering does as many jobs, and heavy loads will remind your shoulder of that versatility.

The romantic's gauge — lovely to carry all day behind a bird dog, as long as you accept a thin ammo aisle and plan ahead.

The smart upland and starter choice — carries light, hits plenty hard, and modern loads have erased most of the old excuses for defaulting to a 12.

The connoisseur's bore — silly-light guns, mild recoil, and surprising killing patterns, at ammo prices that reflect its boutique status.

Laser-flat for a rimfire and devastating on varmints, but the light bullets drift badly in wind and it's strictly a small-game number.

The hottest rimfire going, but a narrow rifle catalog and spotty ammo supply keep it a dedicated varminter's choice rather than a mainstream one.

Cheap, quiet, and nearly recoilless — the cartridge everyone learns on and nobody outgrows, though bulk-pack reliability varies box to box.

A living piece of cartridge history that's now harder to find and pricier per round than the .22 LR that replaced it.

Flatter and harder-hitting than .22 LR on varmints, but ammo costs several times as much and the bark is surprisingly sharp.