.380 ACP Barrel Length vs Velocity

By Cole Harlan, Editor·Data checked Nov 4, 2026·How we verify·Editorial standards·Corrections

.380 ACP velocity by barrel length

Velocity at every published length

Muzzle velocity in feet per second. Longest barrel first. A dash means not tested/published at this length.

Velocity lost per inch

This is how many fps each load loses for every inch cut off, between two lengths. Figures marked “calculated by GunReleases” are (fast velocity − slow velocity) ÷ (long length − short length) from the published points, to 1 decimal. “Tester’s stated avg” figures are the tester’s own.

Best barrel length for .380 ACP: the trade-offs

We don’t pick one length. Here is what the test measured in each common range, and what each choice costs.

• Carry length (3 to 4 in). At 3 in the loads measured 860 to 958 fps. At 4 in the loads measured 907 to 1052 fps.
• Larger pistol length (5 in). At 5 in the loads measured 936 to 1093 fps.
• Carbine length (16 in). At 16 in the loads measured 1056 to 1218 fps.

Going from 16 in to 18 in, 3 of 4 loads measured no faster at 18 in. Example: Speer 90 gr Gold Dot measured 1218 fps at 18 in and 1218 fps at 16 in. These are single test series, and three shots per length leaves room for noise.

• Handling: a longer barrel adds length and weight out front; a shorter one is easier to carry and swing.

Box velocity vs measured

SAAMI’s Z299.3 (centerfire pistol and revolver) sets the velocity test barrel for .380 ACP at 3.750 in, measured at 15 ft. SAAMI notes that your gun will not exactly duplicate test-barrel velocities.

How this was measured

• Test setup. Thompson/Center Encore pistol frame with custom barrels cut down 1 in at a time from 18 in to 2 in; 3 shots of each load at each length; two chronographs; barrel length measured from muzzle to breech face (no revolver cylinder gap); BBTI's 2010 .380 test.
• Where the BBTI page lives. BBTI’s live site returned an error when we checked on Nov 4, 2026, so we link its Internet Archive copy. The original address is http://www.ballisticsbytheinch.com/380auto2.html (plain text, not linked). BBTI is an archived project that has not been updated since 2020.
• Our part. We copied each published number exactly. We did not average, smooth, estimate or fill in any length. A dash means the tester did not publish that length. The underlying measurements belong to the testers credited above; our compilation is CC BY 4.0.
• Limits. This is one test series with one rifle or pistol frame, one chronograph and one day’s weather. Your results will differ.

Download the data

barrel-length-velocity-380-acp.csv has every number on this page with its source and test conditions. The combined file for all calibers and the barrel length vs velocity hub have the rest. Free to reuse under CC BY 4.0.

Frequently asked questions

Related

• Barrel length vs velocity: all calibers
• 9mm Luger barrel length vs velocity
• .40 S&W barrel length vs velocity
• .357 SIG barrel length vs velocity
• .45 ACP barrel length vs velocity
• 10mm Auto barrel length vs velocity
• .38 Special barrel length vs velocity
• .357 Magnum barrel length vs velocity
• .44 Magnum barrel length vs velocity
• .45 Colt barrel length vs velocity
• .22 LR barrel length vs velocity
• .22 WMR (.22 Magnum) barrel length vs velocity
• 5.56 NATO / .223 Rem (AR-15) barrel length vs velocity
• .224 Valkyrie barrel length vs velocity
• 7.62x39 barrel length vs velocity
• .300 Blackout barrel length vs velocity
• .308 Win / 7.62 NATO barrel length vs velocity
• 6.5 Creedmoor barrel length vs velocity
• .243 Winchester barrel length vs velocity
• 7mm Remington Magnum barrel length vs velocity
• .300 Winchester Magnum barrel length vs velocity
• .380 ACP vs 9mm
• .380 ACP ammo 2026
• New ammo for 2026
• All GunReleases data

Sources

1. Ballistics By The Inch (BBTI), .380 ACP test (Internet Archive copy)
2. Ballistics By The Inch: how the tests were done (Internet Archive copy)
3. SAAMI Z299.3 (centerfire pistol and revolver)