The 40 Smith & Wesson is a centerfire handgun cartridge standardised by SAAMI in ANSI/SAAMI Z299.3. SAAMI sets its maximum average pressure at 35,000 psi, and measures its reference velocities in a 4.000 in standard test barrel rifled 1 turn in 16.00 in. This guide sets out SAAMI’s published reference velocity for each bullet weight, computes the muzzle energy each one carries, and compares the 40 Smith & Wesson with the 9mm Luger on the same basis.
40 S&W 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 |
|---|---|---|
| 125 gr | 1,300 fps | 469 ft-lb |
| 135 gr | 1,150–1,185 fps | 396–421 ft-lb |
| 140 gr | 1,050–1,155 fps | 343–415 ft-lb |
| 141 gr | 1,135 fps | 403 ft-lb |
| 155 gr | 1,115–1,195 fps | 428–491 ft-lb |
| 165 gr | 980–1,135 fps | 352–472 ft-lb |
| 180 gr | 985 fps | 388 ft-lb |
| 205 gr | 830 fps | 314 ft-lb |
What the numbers mean for a shot
SAAMI lists 8 reference bullet weights for the 40 Smith & Wesson, from 125 to 205 grains. The lightest, 125 grains, is listed at 1,300 fps, which computes to 469 ft-lb. The heaviest, 205 grains, is listed at 830 fps, which computes to 314 ft-lb. The most energetic reference load is the 155-grain at 1,195 fps: 491 ft-lb computed.
SAAMI lists more than one reference velocity for 135, 140, 155 and 165 grains. Its own note says this is because a weight can carry several introductions meeting different market needs, such as reduced-recoil loads, or because propellant and loading advances allowed higher velocities after the original load appeared.
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 40 S&W ammo range lists whatever its maker publishes for that item.
Barrel, chamber and pressure
SAAMI’s standard test barrel for the 40 Smith & Wesson is 4.000 in long and rifled 1 turn in 16.00 in, with a .4005 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 35,000 psi. Fire 40 Smith & Wesson 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.
40 S&W vs 9mm: 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 | 40 Smith & Wesson | 9mm Luger |
|---|---|---|
| Maximum average pressure | 35,000 psi | 35,000 psi |
| Maximum average pressure, +P | No +P standard | 38,500 psi |
| Standard test barrel length | 4.000 in | 4.000 in |
| Test barrel twist rate | 1 turn in 16.00 in | 1 turn in 10.00 in |
| Test barrel groove diameter | .4005 in | .3550 in |
| Lightest reference load | 125 gr — 1,300 fps / 469 ft-lb | 88 gr — 1,500 fps / 440 ft-lb |
| A weight both list | 135 gr — 1,150–1,185 fps / 396–421 ft-lb | 135 gr — 1,010–1,060 fps / 306–337 ft-lb |
| Heaviest reference load | 205 gr — 830 fps / 314 ft-lb | 150 gr — 900 fps / 270 ft-lb |
The 40 Smith & Wesson and the 9mm Luger share the same maximum average pressure, 35,000 psi. At 135 grains, a weight both list, SAAMI’s 40 Smith & Wesson reference velocity is up to 1,185 fps (421 ft-lb computed), against up to 1,060 fps (337 ft-lb) for the 9mm Luger. On that row the 40 Smith & Wesson carries the more energy. Their standard test barrels differ (4.000 in, 1 turn in 16.00 in for the 40 Smith & Wesson; 4.000 in, 1 turn in 10.00 in for the 9mm Luger), 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: 9mm ammo.
40 S&W ballistics questions
What is the maximum pressure of the 40 Smith & Wesson?
ANSI/SAAMI Z299.3 sets the maximum average pressure for the 40 Smith & Wesson at 35,000 psi.
What twist rate and barrel length does SAAMI use for the 40 Smith & Wesson?
SAAMI’s standard test barrel for the 40 Smith & Wesson is 4.000 in long and rifled 1 turn in 16.00 in. Your own handgun may differ.
What bullet weights does SAAMI list for the 40 Smith & Wesson?
SAAMI lists 8 reference weights, from 125 to 205 grains: 125, 135, 140, 141, 155, 165, 180 and 205.
Is the 40 Smith & Wesson more powerful than the 9mm Luger?
Power is not a SAAMI measure, but reference muzzle energy is a fair proxy. At 135 grains, a weight both list, SAAMI’s 40 Smith & Wesson reference velocity is up to 1,185 fps (421 ft-lb computed), against up to 1,060 fps (337 ft-lb) for the 9mm Luger.
What is the effective range of the 40 Smith & Wesson?
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 40 Smith & Wesson 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 40 S&W ammunition from Federal, Winchester, Underwood, Remington, Hornady and Buffalo Bore. Browse the full 40 S&W ammo range.
