Practice & target
Full-metal-jacket, plated, lead, and wadcutter bullets describe different constructions. Grain weight is projectile mass; it does not state a powder charge or guarantee recoil.
THE CARTRIDGE LIBRARY · PISTOL
.25 ACP
Also written 6.35mm Browning, this is a small semiautomatic-pistol cartridge. ACP refers to Automatic Colt Pistol nomenclature, not a measurement of bullet weight.
2A Ledger reference desk · Sources checked October 18, 2026
Read the dimensions
- Overall · min–max
- 0.860–0.910 in
21.844–23.114 mm - Case length · max
- 0.615 in
15.621 mm - Bullet maximum
- 0.251 in
6.375 mm - Rim diameter · max
- 0.302 in
7.671 mm
Know the exact name
At a glance
- Cartridge family
- Pistol
- Bullet specification
- 0.2510 in / 6.375 mmBullet maximum
- Factory examples
- 5 loadsSelected, sourced examples below
- Weight in cited examples
- 35–50 grGrains measure mass, not powder charge
.25 ACP is identified by its complete cartridge designation. The resource-table alternative is 6.35 Browning. A caliber number, bullet diameter, or family resemblance on its own does not identify ammunition compatibility.
It is unrelated to .25-caliber rifle cartridges such as .25-06 Remington and .257 Roberts.
Dimensions: open the exact dimensional drawing ↗. The displayed number is bullet maximum, rather than an assertion that every manufactured projectile or barrel has this exact diameter.
Origins & evolution
Background & development
John Moses Browning developed the .25 ACP as a centerfire cartridge for exceptionally small automatic pistols. It became closely associated with FN’s early vest-pocket Browning pistol in Europe, where the designation 6.35 mm Browning became familiar, and with Colt’s 1908 Vest Pocket pistol in the United States. These pistols belong to the period when a self-contained cartridge and a compact self-loading action were becoming practical everyday products.
The design’s significance was its packaging as much as its power. A small centerfire primer and a case intended for automatic-pistol feeding offered an alternative to using a rimfire cartridge in a tiny pocket pistol. Its modest performance has long limited its appeal beside larger handgun cartridges, but the enormous number of small .25-caliber pistols explains its persistence. The cartridge should not be confused with the much larger .25-caliber rifle families: the shared caliber number conceals very different origins and dimensions.
Historical sources: Anthony Vanderlinden: original research on FN and Colt vest-pocket Brownings ↗
Construction changes the story
Loads, variations & specialty offerings
Expanding factory bullets
JHP, XTP, FTX, HST, and similar product names refer to particular designs. Muzzle energy alone does not show expansion, penetration, or reliability in a particular firearm.
Specialty load families
Reduced-recoil, subsonic, monolithic, and heavier-bullet offerings are product-specific. A +P marking is a pressure category where standardized, not simply a heavier bullet. Follow the maker’s exact product and firearm guidance.
The expanded factory selection spans 35–50 grains. Exact products and source conditions appear in the table.
Bullet construction background: Hornady: anatomy of a bullet ↗. Exact product descriptions and velocities are cited in the factory table.
The table also distinguishes ordinary factory loads. Published test conditions and product-specific notes accompany each addition; no velocity curve is inferred from one muzzle specification.
From the factory catalog
35 grains
900 fps
XTP®
45 grains
825 fps
SOLID
50 grains
760 fps
FMJ
Compare all 5 cited factory load records
| Maker / product | Bullet mass | Published construction | Muzzle velocity | Test barrel | Source |
|---|---|---|---|---|---|
| Hornady90012 | 35 gr 2.27 g | XTP® | 900 fps 274 m/s | 2 in | Hornady · PDF p. 191 ↗ |
| Hornady90014 | 35 gr 2.27 g | FTX® | 900 fps 274 m/s | 2 in | Hornady · PDF p. 191 ↗ |
| FederalPD25P1 | 45 gr 2.92 g | SOLID | 825 fps 251 m/s | 2 in | Federal · PDF p. 60 ↗ |
| FederalAE25AP | 50 gr 3.24 g | FMJ | 760 fps 232 m/s | 2 in | Federal · PDF p. 61 ↗ |
| Fiocchi25AP | 50 gr 3.24 g | FMJStandard factory load. Its published velocity is not a guarantee of subsonic performance in every firearm or temperature. | 800 fps 243.8 m/s | Not stated | Fiocchi · PDF p. 31 ↗ |
Explore the published data
Ballistics you can inspect
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
.25 ACP: velocity by barrel length
| Exact load | Source / publisher | Published points |
|---|---|---|
| American Eagle 50 gr. TMJ | BBTI | 2: 753; 3: 867; 4: 847; 5: 904; 6: 963; 7: 1,003; 8: 1,000; 9: 982; 10: 1,025; 11: 1,023; 12: 1,015; 13: 1,003; 14: 1,016; 15: 999; 16: 1,005; 17: 997; 18: 1,049 |
| Winchester 45 gr. expanding point | BBTI | 2: 816; 3: 850; 4: 896; 5: 902; 6: 939; 7: 970; 8: 951; 9: 951; 10: 994; 11: 999; 12: 979; 13: 996; 14: 986; 15: 991; 16: 977; 17: 996; 18: 1,001 |
| Winchester 50 gr. FMJ | BBTI | 2: 780; 3: 903; 4: 942; 5: 949; 6: 983; 7: 1,007; 8: 982; 9: 1,005; 10: 997; 11: 1,001; 12: 1,014; 13: 1,023; 14: 1,057; 15: 1,032; 16: 1,026; 17: 980; 18: 978 |
.25 ACP: factory velocity downrange
| Exact load | Source / publisher | Published points |
|---|---|---|
| 35 gr Hornady XTP® | Hornady | 0: 900; 50: 813; 100: 742 |
| 45 gr Federal SOLID | Federal | 0: 825; 25: 795; 50: 766; 75: 739; 100: 714 |
| 50 gr Federal FMJ | Federal | 0: 760; 25: 738; 50: 717; 75: 697; 100: 677 |
| 35 gr Hornady FTX® | Hornady | 0: 900; 50: 805; 100: 728 |
| 50 gr Fiocchi FMJ | Fiocchi | 0: 800 |
How to interpret the comparison
Changing bullet weight also often changes bullet design and propellant choice. Two curves are comparisons of the listed products, not a controlled experiment proving that bullet weight alone caused the difference. Catalog downrange points are projections under the maker’s conditions; barrel-study points are recorded observations in the study firearm.
Direct answers
Common questions
What is .25 ACP?
Also written 6.35mm Browning, this is a small semiautomatic-pistol cartridge. ACP refers to Automatic Colt Pistol nomenclature, not a measurement of bullet weight.
What diameter does .25 ACP use?
The cited dimensional standard lists 0.2510 inches (6.375 mm), bullet maximum. This drawing convention is different from a casual caliber nickname.
Are similarly named cartridges interchangeable?
It is unrelated to .25-caliber rifle cartridges such as .25-06 Remington and .257 Roberts.
Are the graph values measured or estimated?
Factory datasets show manufacturer specifications and any published downrange projections. Chronograph and barrel-study datasets identify recorded measurements and the original test source. Dashed connectors and intermediate inspector values are labeled linear estimates; single source points are not extended into invented curves. Energy is calculated from 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
Skives & petals: read the jacket construction →
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. 38 ↗
- Sierra: .25 ACP cartridge background ↗
- Hornady · PDF p. 191 ↗
- Federal · PDF p. 60 ↗
- Federal · PDF p. 61 ↗
- Ballistics by the Inch: archived measured barrel data (2020 archive) ↗
- BBTI: study index and source records ↗
- Anthony Vanderlinden: original research on FN and Colt vest-pocket Brownings ↗
- Additional factory specification / original test ↗
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.