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
16 gauge
A conventional shotgun gauge between 12 and 20 in bore size. Current factory examples include upland birdshot, selected buckshot, and slugs.
2A Ledger reference desk · Sources checked October 18, 2026
Read the dimensions
- Folded length · max
- 2.440 in
61.976 mm - Nominal shell class
- 2¾ in
69.850 mm - Bore diameter · min
- 0.665 in
16.891 mm - Rim diameter · max
- 0.819 in
20.803 mm
Know the exact name
At a glance
- Cartridge family
- Shotshell
- Bore specification
- 0.6650 in / 16.891 mmBore minimum
- Factory examples
- 4 shot loadsSelected catalog examples
- Weight in cited examples
- Ounces / pellet countPayload is separate from gauge
16 gauge is identified by its complete cartridge designation. The resource-table alternative is 16 ga. A caliber number, bullet diameter, or family resemblance on its own does not identify ammunition compatibility.
16 is the gauge, not a shot-size number. A larger-numbered birdshot pellet is smaller within the named U.S. shot-size convention.
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 16 gauge has a long sporting history as a middle ground between the larger 12 and smaller 20. Its following became particularly associated with upland hunting and trim field guns. Browning’s Sweet Sixteen, introduced during the 1930s, made that identity especially recognizable: a lighter version of the Auto-5 that paired the gauge with a distinctive long-recoil autoloading shotgun.
The gauge retained devoted users even as the 12 and 20 occupied more of the general market. Browning’s return to the Sweet Sixteen name in 2016 demonstrates that continuity, but the new A5 used an inertia-operated system rather than reproducing the original Auto-5 mechanism. That is an important historical distinction behind a familiar name and silhouette. The 16 gauge’s story is less about ever-larger magnum payloads than about the balance and handling of the guns built around it, and the loyalty those sporting guns inspired across generations.
Historical sources: Browning: original Sweet Sixteen history and the 2016 A5 revival ↗ · Browning: company timeline of Auto-5 and Sweet Sixteen development ↗
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 |
|---|---|---|---|---|---|
| PWBX167 | Steel birdshot | 2¾ | ⅞ oz | 2, 4 | 1,450 fps 442 m/s |
| PHBX163 | Bismuth birdshot | 2¾ | 1⅛ oz | 3, 4, 5 | 1,400 fps 427 m/s |
| PF163 | Lead field birdshot | 2¾ | 1⅛ oz | 4, 5, 6 | 1,425 fps 434 m/s |
| F164 1B | Lead buckshot | 2¾ | 12 pellets | 1 buck | 1,225 fps 373 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
16 gauge: factory velocity downrange
| Exact load | Source | Published points |
|---|---|---|
| 350 gr Federal 2¾-inch rifled hollow-point slug | Federal | 0: 1600; 25: 1380; 50: 1210; 75: 1080; 100: 1000; 125: 930 |
Source records for plotted slugs
| Maker / product | Bullet mass | Published construction | Muzzle velocity | Test barrel | Source |
|---|---|---|---|---|---|
| FederalF164 RS | 350 gr 22.68 g | 2¾-inch rifled hollow-point slug | 1,600 fps 488 m/s | 28 in | Federal · PDF p. 63 ↗ |
Direct answers
Common questions
What is 16 gauge?
A conventional shotgun gauge between 12 and 20 in bore size. Current factory examples include upland birdshot, selected buckshot, and slugs.
Is 16 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?
16 is the gauge, not a shot-size number. A larger-numbered birdshot pellet is smaller within the named U.S. shot-size convention.
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. 33 ↗
- Federal: shotshell components and nominal shot sizes ↗
- Federal: 2026 ammunition catalog ↗
- Federal · PDF p. 63 ↗
- Browning: original Sweet Sixteen history and the 2016 A5 revival ↗
- Browning: company timeline of Auto-5 and Sweet Sixteen development ↗
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.