The Big Page of Cartridge Comparisons
Rifle and Pistol Ammo 
Pistol Rounds 
9mm Ammo Variations
From left: 9x19mm Parabellum; 7.62x25mm Tokarev; .357 SIG; 10 mm Auto; .40 S&W; .45 GAP; .50 Action Express
From left to right: 7.62x51 for scale; 6mm Lee; 5.2mm Mondragon; 5mm Sturtevant
Left to right: .460 S&W Magnum; .454 Casull; .44 Magnum; .45ACP; .22LR
Left to Right: 1) .17 HM2; 2) .17 HMR; 3) .22LR; 4) .22 WMR; 5) .17 SMc; 6) 5mm/35 SM4; 7) .22 Hornet; 8) .223 Remington; 9).223 WSSM; 10) .243 Winchester; 11) .243 Winchester Improved (Ackley); 12) .25-06; 13) .270 Winchester; 14) .308; 15) .30-06; 16) .45-70 Govt; 17) .50-90 Sharps
Common Pistol Cartridge Comparison
Left to right: 1) 3 inch 12 ga magnum shotgun shell; 2) AA battery (for size comparison); 3) .454 Casull; 4) .45 Winchester Magnum;
5) .44 Remington Magnum; 6) .357 Magnum; 7) .38 Special; 8) .45 ACP; 9) .38 Super; 10) 9 mm Luger; 11) .32 ACP; 12) .22 LR
From left to right: 9x19 mm Parabellum; .40 S&W; .45 ACP; 5.7x28mm; 5.56x45 mm NATO;
.300 Winchester Magnum; and a 70 mm (2.75 inches) and 76 mm (3 inches) 12 gauge
Rounds for early automatic rifles: the 6.5x52 Carcano; 7.65 Mannlicher Carbine;
.30 Pedersen; 8mm Ribeyrolle (replica); Swiss 7.65x35; .276 Pedersen;
Swiss 7.65x38 with bullet alongside; 9x40 Lahti; 9x35 Lahti
Unsuccessful postwar experiments: 7x36 Otterup; 7.5x38 Swiss;7.5x45 Czech;7.5x43 French CRBA; 7.92x40 CETME; .280/30 EM-2; 7mm Compromise;
7.62x47 T65 (predecessor of the 7.62x51 NATO); 7.62x51 with CETME bullet.
Some experimental US rounds of the 1950s: .223 Remington (for scale); .224 Winchester E2;
.25 Win FA-T 116 (6.35x48); .25 Win Duplex FA-T 127 (6.35x53); .22/30 Homologous (5.56x51);
.27/30 Homologous (6.8x51); .25/30 Homologous (6.35x51); sectioned 7.62x51 M198 Duplex (which actually saw service).
Intermediate service cartridges: 6.5mm Arisaka; 7mm Medium; .30 M1 Carbine;
7.92mm Kurz; 7.62mm AK-47; 7.62x45 Czech; 9x39 Russian (silenced AP - replica round);
5.56x45 SS109; 5.45x39 AK-74; 5.8x42 Chinese
Some experiments since the 1970s: 6mm SAW; 6mm SAW aluminum-cased; 6.25mm British;
6.45mm Swiss; 6.5x43 German; 6.8x43 Remington SPC (commercial soft-point bullet loading:
military bullets are shorter to match the overall length of the 5.56x45); 6.5mm Grendel; 5.56x45 for scale
Experimental cartridges under 6mm: FN 5.56x45 APDS; .12 US (3x47); 3.5x50 FN;
4.3x45 German; .17 US (4.3x46); 4.6x36 HK/CETME (with spoon-tip bullet);
4.85mm British; 5.56x38 FABRL; 5.6mm Eiger
Experimental US flechette rounds: 5.56x45 for scale; sectioned 5.6mm XM216;
5.6mm XM144; 5.6mm XM110; 5.6mm XM645 (all part of the SPIW programme);
.330 Amron Aerojet (alloy case; with three flechettes)
Exotic attempts: 5.56x45 with Monad bullet; 4.5mm Schirnecker; 9/4mm Kaltmann
(development round; with part-metal case); 5.56mm Folded; 5.56mm Hughes Lockless;
5.56mm US caseless; 6mm Voere caseless; early HK G11 4.7x21 rounds; final G11 4.7x33
G11 4.7x33 Components; Charge; Primer; Projectile; Retainer 
Common Ammo Comparison 
The Rare 9mm Winchester Magnum (9x29) Used mainly in the AMT AutoMAG
III
Different 45s
Specialty Ammo
12ga Rifle From Hell shell comparison (the biggest black tipped round is a .50 BMG round!)
.17HM2; .17HMR; .22LR; .22WMR; 5.7FN; .223Rem.; .243Win.; 6mmRem.; .25-20Win.; .264WM; .270WSM; 7x57mmMauser; 7mmRUM; .30Carbine;
7.62x39mm; .30-30Win.; .308Win. (actually 7.62NATO tracer); .303British (Cordite charge with Cupro-nickel jacket projectile); .30-06; .300WM; .300Wby.;
8x57mmMauser; .35Rem.; .375H&H; .45-70Govt.; .458WM; .460Wby.; .50Beowulf; .50BMG (AP); .577NE; .577T-Rex; 12GaFH; .700NE; and finally Mr. Hubel's 4Bore.
More "12ga Rifle From Hell" shell comparisons
505 Gibbs, 585 Hubel Super_Magnum 
The 458 SOCOM
The 458 SOCOM
From left to right: 5.56x45; .458 SOCOM; .50 Beowulf; .499 LWR
.30 HRT (110 grain Hornady V-Max); .338 Spectre - 300 grain Sierra Hollow Point Boat Tail Match King) and 300 grain HAWK Round Nose;
.458 SOCOM - 300 grain Barnes X Spitzer; 400 grain Barnes Round Nose Solid and 600 grain Barnes Original;
.500 Phantom - 168 grain Sierra HPBTMK (saboted); 700 grain HAWK and 750 grain Hornady A-Max.
14.9 SOP, necked down 20mm Vaulkan round!
https://www.50westarmory.com/149mm
Badly cracked .303 British rifle casing
Assorted Common Shotgun Projectiles 
Shotgun Choke Patterns