The 458 Lott is a centerfire rifle cartridge standardised by SAAMI in ANSI/SAAMI Z299.4. SAAMI sets its maximum average pressure at 62,500 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 458 Lott with the 458 Winchester Magnum on the same basis.
458 Lott 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 |
|---|---|---|
| 465 gr | 2,380 fps | 5,848 ft-lb |
| 500 gr | 2,150–2,300 fps | 5,131–5,872 ft-lb |
What the numbers mean for a shot
SAAMI lists two reference bullet weights for the 458 Lott, 465 and 500 grains. The lighter, 465 grains, is listed at 2,380 fps, which computes to 5,848 ft-lb. The heavier, 500 grains, is listed at 2,150–2,300 fps, which computes to 5,131–5,872 ft-lb.
SAAMI lists more than one reference velocity for 500 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 458 Lott ammo range lists whatever its maker publishes for that item.
Twist rate, chamber and pressure
SAAMI’s standard test barrel for the 458 Lott is 24.000 in long and rifled 1 turn in 10.00 in, with a .458 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 62,500 psi. Fire 458 Lott 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.
458 Lott vs 458 Win Mag: 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 | 458 Lott | 458 Winchester Magnum |
|---|---|---|
| Maximum average pressure | 62,500 psi | 60,000 psi |
| Standard test barrel length | 24.000 in | 24.000 in |
| Test barrel twist rate | 1 turn in 10.00 in | 1 turn in 14.00 in |
| Test barrel groove diameter | .458 in | .458 in |
| Lightest reference load | 465 gr — 2,380 fps / 5,848 ft-lb | 400 gr — 2,250 fps / 4,496 ft-lb |
| A weight both list | 500 gr — 2,150–2,300 fps / 5,131–5,872 ft-lb | 500 gr — 2,025–2,240 fps / 4,552–5,570 ft-lb |
| Heaviest reference load | 500 gr — 2,150–2,300 fps / 5,131–5,872 ft-lb | 510 gr — 2,025 fps / 4,643 ft-lb |
SAAMI standardises the 458 Lott at 62,500 psi and the 458 Winchester Magnum at 60,000 psi, so the 458 Lott runs 2,500 psi higher. At 500 grains, a weight both list, SAAMI’s 458 Lott reference velocity is up to 2,300 fps (5,872 ft-lb computed), against up to 2,240 fps (5,570 ft-lb) for the 458 Winchester Magnum. On that row the 458 Lott carries the more energy. Their standard test barrels differ (24.000 in, 1 turn in 10.00 in for the 458 Lott; 24.000 in, 1 turn in 14.00 in for the 458 Winchester Magnum), 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: 458 Win Mag ammo.
458 Lott ballistics questions
What is the maximum pressure of the 458 Lott?
ANSI/SAAMI Z299.4 sets the maximum average pressure for the 458 Lott at 62,500 psi.
What twist rate and barrel length does SAAMI use for the 458 Lott?
SAAMI’s standard test barrel for the 458 Lott is 24.000 in long and rifled 1 turn in 10.00 in. Your own rifle may differ.
What bullet weights does SAAMI list for the 458 Lott?
SAAMI lists 2 reference weights, from 465 to 500 grains: 465 and 500.
Is the 458 Lott more powerful than the 458 Winchester Magnum?
Power is not a SAAMI measure, but reference muzzle energy is a fair proxy. At 500 grains, a weight both list, SAAMI’s 458 Lott reference velocity is up to 2,300 fps (5,872 ft-lb computed), against up to 2,240 fps (5,570 ft-lb) for the 458 Winchester Magnum.
What is the effective range of the 458 Lott?
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 458 Lott 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.
Where to buy these loads
Hilltop Armory carries 458 Lott ammunition from Federal, Barnes, Hornady and Kynoch. Browse the full 458 Lott ammo range.
