Birdshot
Many smaller pellets form a pattern. In the U.S. size examples below, a higher birdshot number means a smaller pellet. Lead, steel, bismuth, and tungsten-based products of the same numbered size need not have the same mass or behavior.
THE CARTRIDGE LIBRARY · SHOTSHELL
12 gauge
A broad shotgun gauge family encompassing target birdshot, hunting shot, buckshot, and slugs. Gauge alone tells you neither pellet size nor payload.
2A Ledger reference desk · Sources checked October 18, 2026
Read the dimensions
- Folded length · max
- 2.405 in
61.087 mm - Nominal shell class
- 2¾ in
69.850 mm - Bore diameter · min
- 0.725 in
18.415 mm - Rim diameter · max
- 0.886 in
22.504 mm
Know the exact name
At a glance
- Cartridge family
- Shotshell
- Bore specification
- 0.7250 in / 18.415 mmBore minimum
- Factory examples
- 5 shot loadsSelected catalog examples
- Weight in cited examples
- Ounces / pellet countPayload is separate from gauge
12 gauge is identified by its complete cartridge designation. The resource-table alternative is 12 ga. A caliber number, bullet diameter, or family resemblance on its own does not identify ammunition compatibility.
Short shells, magnum shells, rifled slugs, and sabot slugs have different firearm requirements. Match both the gauge and the maker's chamber/load guidance.
Dimensions: open the exact dimensional drawing ↗. The displayed number is bore minimum, rather than an assertion that every manufactured projectile or barrel has this exact diameter.
Origins & evolution
Background & development
The 12 gauge developed through the broader transition from muzzleloading shotguns to self-contained shotshells, repeaters and autoloaders; it does not have one modern cartridge inventor or launch date. By the early twentieth century it was firmly established in sporting arms. Winchester’s Model 1897 illustrates how the same gauge crossed roles, moving from sporting use into the U.S. military’s trench-shotgun program during World War I.
Its twentieth-century development was also an ammunition story. Winchester introduced the AA target-shotshell line in 1965, and its later anniversary history records a long association with major clay-target championships. Purpose-built target loads, heavier field loads, buckshot and slugs allowed one gauge to serve very different markets. That breadth helped sustain the 12 gauge’s central position while manufacturers refined hulls, wads and projectile materials. A useful history therefore follows both the guns and the ammunition industries, rather than treating all 12-gauge shells as one unchanged load.
Historical sources: Winchester: Model 1897 and 1918 military shotgun history ↗ · Winchester: original 1965 AA introduction and target-shooting legacy ↗
Construction changes the story
Loads, variations & specialty offerings
Gauge identifies the bore family. Shot number identifies the approximate diameter of an individual pellet. Ounces describe the combined shot payload, while a buckshot product may specify a pellet count. Shell length is a separate chamber-fit specification, normally referenced to the fired shell.
Buckshot
Fewer, larger pellets are commonly listed by size and pellet count. #4 birdshot and #4 buckshot have very different diameters. Pattern behavior depends on the exact load, firearm, and choke; there is no universal inches-per-yard rule.
Slugs
A slug is a single projectile. Rifled/Foster-type and sabot designs have different barrel recommendations. Federal identifies sabot loads for rifled barrels; follow the exact ammunition and barrel maker’s instructions.
Materials & specialty loads
Lead & bismuth
Lead remains common in target and upland loads where permitted. Bismuth is an alternative material offered in selected sporting loads; compare the maker’s product specification and shotgun/choke compatibility.
Steel
Steel shot has different density and hardness from lead. A shot-size label alone does not reproduce the same pellet mass. Use ammunition approved for the barrel and choke; check current local hunting requirements separately.
Tungsten-based & specialty
TSS and other tungsten-based products can use small pellets and dense payloads. The exact alloy and construction matter. Mixed-shot, reduced-recoil, short-shell, and handgun-marketed products retain their own firearm restrictions.
Compare pellet sizes visually
The two circles use the same screen scale to compare nominal pellet diameter. They are not life-size, do not represent a shot pattern, and do not show an individual load’s pellet count.
See nominal pellet sizes in inches and millimeters
| Pellet | Inches | Millimeters |
|---|---|---|
| #9 birdshot | 0.08 | 2.032 |
| #8 birdshot | 0.09 | 2.286 |
| #7½ birdshot | 0.095 | 2.413 |
| #6 birdshot | 0.11 | 2.794 |
| #5 birdshot | 0.12 | 3.048 |
| #4 birdshot | 0.13 | 3.302 |
| #3 birdshot | 0.14 | 3.556 |
| #2 birdshot | 0.15 | 3.810 |
| #1 birdshot | 0.16 | 4.064 |
| BB birdshot | 0.18 | 4.572 |
| BBB birdshot | 0.19 | 4.826 |
| T birdshot | 0.2 | 5.080 |
| #4 buckshot | 0.24 | 6.096 |
| #3 buckshot | 0.25 | 6.350 |
| #2 buckshot | 0.27 | 6.858 |
| #1 buckshot | 0.3 | 7.620 |
| 00 buckshot | 0.33 | 8.382 |
| 000 buckshot | 0.36 | 9.144 |
Federal: shotshell components and nominal shot sizes ↗
Factory shot-load examples
| Product code | Load family | Shell length (in) | Payload | Shot size | Muzzle velocity |
|---|---|---|---|---|---|
| PWBX142 | Steel birdshot | 3 | 1¼ oz | BB, 2, 3, 4 | 1,450 fps 442 m/s |
| HVF12 | Lead target birdshot | 2¾ | 1⅛ oz | 7½, 8 | 1,275 fps 389 m/s |
| F12700 | Lead buckshot | 2¾ | 9 pellets | 00 | 1,325 fps 404 m/s |
| H13200 | Reduced-recoil buckshot | 2¾ | 9 pellets | 00 | 1,140 fps 347 m/s |
| PD129FX2 00 | Short-shell segmented buckshot | 1¾ | 6 pellets | 00 | 1,245 fps 379 m/s |
Explore the published data
Ballistics you can inspect
Shotshell muzzle velocity, pellet patterns, and slug trajectories answer different questions. Birdshot and buckshot cannot be represented as a single bullet curve: individual pellet drag and pattern behavior require a load-specific test. The pellet comparison above shows size, not performance.
Select a legend entry to add or remove its line. Hover or tap a plotted point, or use the position slider. With the graph focused, arrow keys move the inspector. Solid dots identify source points; dashed connectors show estimates between them. Load construction, pressure category, and test setup can differ even at the same grain weight.
Read the original values as accessible tables
12 gauge: factory velocity downrange
| Exact load | Source | Published points |
|---|---|---|
| 300 gr Federal 3-inch copper sabot | Federal | 0: 2000; 25: 1900; 50: 1800; 100: 1620; 150: 1450; 200: 1310 |
| 438 gr Federal 2¾-inch rifled hollow-point slug | Federal | 0: 1610; 25: 1470; 50: 1340; 75: 1230; 100: 1140; 125: 1070 |
| 300 gr Federal 2¾-inch copper sabot | Federal | 0: 1900; 25: 1800; 50: 1710; 100: 1530; 150: 1380; 200: 1240 |
Source records for plotted slugs
| Maker / product | Bullet mass | Published construction | Muzzle velocity | Test barrel | Source |
|---|---|---|---|---|---|
| FederalP151 FT | 300 gr 19.44 g | 3-inch copper sabot | 2,000 fps 610 m/s | 30 in | Federal · PDF p. 63 ↗ |
| FederalP152 FT | 300 gr 19.44 g | 2¾-inch copper sabot | 1,900 fps 579 m/s | 30 in | Federal · PDF p. 63 ↗ |
| FederalF127 RS | 438 gr 28.38 g | 2¾-inch rifled hollow-point slug | 1,610 fps 491 m/s | 30 in | Federal · PDF p. 63 ↗ |
Direct answers
Common questions
What is 12 gauge?
A broad shotgun gauge family encompassing target birdshot, hunting shot, buckshot, and slugs. Gauge alone tells you neither pellet size nor payload.
Is 12 gauge a shot size?
Gauge or bore identifies the shell and bore family. Birdshot and buckshot size labels describe individual pellets. The load also needs a payload, shell length, material, and exact product identification.
Are similarly named cartridges interchangeable?
Short shells, magnum shells, rifled slugs, and sabot slugs have different firearm requirements. Match both the gauge and the maker's chamber/load guidance.
Are the graph values measured or estimated?
The downrange view uses the exact manufacturer catalog records shown in the source table. Dashed connectors and intermediate inspector values use linear interpolation between the displayed source points. Calculated energy uses the listed bullet mass and velocity.
Does higher energy mean the best load?
Energy is calculated from mass and velocity. It does not establish accuracy, expansion, penetration, pattern density, recoil, or suitability for a particular firearm. Use the exact product documentation and firearm manual.
Trace the facts
Sources & methodology
Compiled by 2A Ledger from the linked standards, manufacturer publications, and identified test records. Checked October 18, 2026. Historical tests and older catalogs retain their original dates; a listing here does not establish current availability.
- SAAMI: dimensional drawing · PDF p. 28 ↗
- Federal: shotshell components and nominal shot sizes ↗
- Federal: 2026 ammunition catalog ↗
- Federal · PDF p. 63 ↗
- Winchester: Model 1897 and 1918 military shotgun history ↗
- Winchester: original 1965 AA introduction and target-shooting legacy ↗
Diameter figures preserve the cited drawing convention. Inch–millimeter conversion uses exactly 25.4 mm per inch. Factory specifications describe the maker’s test setup; your firearm, ammunition lot, temperature, and measuring method can produce different results. This is an educational factory-ammunition reference, not a reloading manual.