The 338 Federal is a centerfire rifle cartridge standardised by SAAMI in ANSI/SAAMI Z299.4. SAAMI sets its maximum average pressure at 62,000 psi, and measures its reference velocities in a 24.000 in standard test barrel rifled 1 turn in 10.00 in. This guide sets out SAAMI’s published reference velocity for each bullet weight, computes the muzzle energy each one carries, and compares the 338 Federal with the 308 Winchester on the same basis.
338 Federal 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 |
|---|---|---|
| 180 gr | 2,830 fps | 3,200 ft-lb |
| 185 gr | 2,750 fps | 3,106 ft-lb |
| 200 gr | 2,630 fps | 3,071 ft-lb |
| 210 gr | 2,630 fps | 3,225 ft-lb |
What the numbers mean for a shot
SAAMI lists 4 reference bullet weights for the 338 Federal, from 180 to 210 grains. The lightest, 180 grains, is listed at 2,830 fps, which computes to 3,200 ft-lb. The heaviest, 210 grains, is listed at 2,630 fps, or 3,225 ft-lb.
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 338 Federal ammo range lists whatever its maker publishes for that item.
Twist rate, chamber and pressure
SAAMI’s standard test barrel for the 338 Federal is 24.000 in long and rifled 1 turn in 10.00 in, with a .338 in groove diameter. That is the barrel every reference velocity above was measured in, not a statement about your rifle: a shorter production barrel will usually give lower velocity, and a twist slower than a bullet needs will not stabilise it. The maximum average pressure is 62,000 psi. Fire 338 Federal 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.
338 Federal vs 308: 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 | 338 Federal | 308 Winchester |
|---|---|---|
| Maximum average pressure | 62,000 psi | 62,000 psi |
| Standard test barrel length | 24.000 in | 24.000 in |
| Test barrel twist rate | 1 turn in 10.00 in | 1 turn in 12.00 in |
| Test barrel groove diameter | .338 in | .308 in |
| Lightest reference load | 180 gr — 2,830 fps / 3,200 ft-lb | 55 gr — 3,750 fps / 1,717 ft-lb |
| A weight both list | 200 gr — 2,630 fps / 3,071 ft-lb | 200 gr — 2,440 fps / 2,643 ft-lb |
| Heaviest reference load | 210 gr — 2,630 fps / 3,225 ft-lb | 200 gr — 2,440 fps / 2,643 ft-lb |
The 338 Federal and the 308 Winchester share the same maximum average pressure, 62,000 psi. At 200 grains, a weight both list, SAAMI’s 338 Federal reference load is 2,630 fps and 3,071 ft-lb computed, against 2,440 fps and 2,643 ft-lb for the 308 Winchester. On that row the 338 Federal carries the more energy. Their standard test barrels differ (24.000 in, 1 turn in 10.00 in for the 338 Federal; 24.000 in, 1 turn in 12.00 in for the 308 Winchester), 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: 308 ammo.
338 Federal ballistics questions
What is the maximum pressure of the 338 Federal?
ANSI/SAAMI Z299.4 sets the maximum average pressure for the 338 Federal at 62,000 psi.
What twist rate and barrel length does SAAMI use for the 338 Federal?
SAAMI’s standard test barrel for the 338 Federal is 24.000 in long and rifled 1 turn in 10.00 in. Your own rifle may differ, and a twist slower than a long, heavy bullet needs will not stabilise it.
What bullet weights does SAAMI list for the 338 Federal?
SAAMI lists 4 reference weights, from 180 to 210 grains: 180, 185, 200 and 210.
Is the 338 Federal more powerful than the 308 Winchester?
Power is not a SAAMI measure, but reference muzzle energy is a fair proxy. At 200 grains, a weight both list, SAAMI’s 338 Federal reference load is 2,630 fps and 3,071 ft-lb computed, against 2,440 fps and 2,643 ft-lb for the 308 Winchester.
How much does the 338 Federal drop at 300 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.
What is the effective range of the 338 Federal?
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.
Where to buy these loads
Hilltop Armory carries 338 Federal ammunition from Federal. Browse the full 338 Federal ammo range.
