The 25 Automatic is a centerfire handgun cartridge standardised by SAAMI in ANSI/SAAMI Z299.3. SAAMI sets its maximum average pressure at 25,000 psi, and measures its reference velocities in a 2.000 in standard test barrel rifled 1 turn in 16.00 in, left hand. This guide sets out SAAMI’s published reference velocity for each bullet weight, computes the muzzle energy each one carries, and compares the 25 Automatic with the 32 Automatic on the same basis.
25 ACP ballistics chart: SAAMI reference data
SAAMI publishes one nominal mean instrumental velocity for each reference bullet weight, measured at 15 feet from the standard test barrel. It does not publish energy, so the ft-lb column is computed. Where SAAMI lists more than one velocity for a weight, both ends of the span are shown.
Scroll the table sideways for the remaining columns.
| Bullet weight | Reference velocity | Computed muzzle energy |
|---|---|---|
| 35 gr | 900 fps | 63 ft-lb |
| 45 gr | 805 fps | 65 ft-lb |
| 50 gr | 755 fps | 63 ft-lb |
What the numbers mean for a shot
SAAMI lists 3 reference bullet weights for the 25 Automatic, from 35 to 50 grains. The lightest, 35 grains, is listed at 900 fps, which computes to 63 ft-lb. The heaviest, 50 grains, is listed at 755 fps, which computes to 63 ft-lb. The most energetic reference load is the 45-grain at 805 fps: 65 ft-lb computed.
None of this is a downrange figure. SAAMI measures at 15 feet, so retained velocity, energy and drop depend on the bullet’s ballistic coefficient, which SAAMI does not publish. Each product in our 25 ACP ammo range lists whatever its maker publishes for that item.
Barrel, chamber and pressure
SAAMI’s standard test barrel for the 25 Automatic is 2.000 in long and rifled 1 turn in 16.00 in, left hand, with a .250 in groove diameter. That is the barrel every reference velocity above was measured in, not a statement about your handgun: handgun barrels vary widely in length, and a shorter barrel gives lower velocity. The maximum average pressure is 25,000 psi. Fire 25 Automatic ammunition only in a firearm chambered for it. Several unrelated cartridges share a number, so match the full designation on the box to the marking on your barrel.
25 ACP vs 32 ACP: the SAAMI comparison
A figure from one maker’s catalogue cannot be laid beside a figure from another’s: each picks its own test barrel, zero and bullet, and many publish no test barrel at all. SAAMI is the shared basis, because it fixes one standard test barrel and one way of measuring velocity for every cartridge it lists.
Scroll the table sideways for the remaining columns.
| SAAMI specification | 25 Automatic | 32 Automatic |
|---|---|---|
| Maximum average pressure | 25,000 psi | 20,500 psi |
| Standard test barrel length | 2.000 in | 4.000 in |
| Test barrel twist rate | 1 turn in 16.00 in, left hand | 1 turn in 16.00 in, left hand |
| Test barrel groove diameter | .250 in | .3110 in |
| Lightest reference load | 35 gr — 900 fps / 63 ft-lb | 60 gr — 970 fps / 125 ft-lb |
| Heaviest reference load | 50 gr — 755 fps / 63 ft-lb | 71 gr — 900 fps / 128 ft-lb |
SAAMI standardises the 25 Automatic at 25,000 psi and the 32 Automatic at 20,500 psi, so the 25 Automatic runs 4,500 psi higher. SAAMI lists no bullet weight in common for the two, so there is no like-for-like velocity row to compare. Their standard test barrels differ (2.000 in, 1 turn in 16.00 in, left hand for the 25 Automatic; 4.000 in, 1 turn in 16.00 in, left hand for the 32 Automatic), so compare the reference rows with that in mind.
What SAAMI cannot settle is anything past the muzzle. It publishes no ballistic coefficients and no downrange data, so it cannot say which cartridge shoots flatter at distance; that depends on the bullet. We stock the other side of this comparison too: 32 ACP ammo.
25 ACP ballistics questions
What is the maximum pressure of the 25 Automatic?
ANSI/SAAMI Z299.3 sets the maximum average pressure for the 25 Automatic at 25,000 psi.
What twist rate and barrel length does SAAMI use for the 25 Automatic?
SAAMI’s standard test barrel for the 25 Automatic is 2.000 in long and rifled 1 turn in 16.00 in, left hand. Your own handgun may differ.
What bullet weights does SAAMI list for the 25 Automatic?
SAAMI lists 3 reference weights, from 35 to 50 grains: 35, 45 and 50.
Is the 25 Automatic more powerful than the 32 Automatic?
SAAMI lists no bullet weight in common for the two, so there is no like-for-like row. Its highest computed reference energy is 65 ft-lb for the 25 Automatic (45 grains) and 144 ft-lb for the 32 Automatic.
What is the effective range of the 25 Automatic?
Effective range is not a SAAMI specification and it is not a measured figure. SAAMI measures velocity at 15 feet, so it says nothing about performance at distance; that depends on the bullet and the shooter.
How much does the 25 Automatic drop at 100 yards?
SAAMI publishes muzzle velocity only, so it cannot give a drop figure. Drop depends on the bullet’s ballistic coefficient and on the zero range. A drop figure is unusable without its zero, so use the figure a maker prints for the specific load.
Where to buy these loads
Hilltop Armory carries 25 ACP ammunition from Buffalo Bore, Federal, Hornady, Aguila, Blazer and Magtech. Browse the full 25 ACP ammo range.
