The 300 Whisper is a cartridge based on the 221 Remington case necked up to 30 caliber, developed by J.D. Jones of SSK Industries, and loaded by Hornady in subsonic and supersonic versions for the AR-15 platform.
The 300 Whisper is not listed in SAAMI’s rifle (Z299.4), handgun (Z299.3) or rimfire (Z299.1) standards, so there is no SAAMI reference velocity, pressure limit or test barrel to quote for it. This guide charts what the makers of the loads we stock publish for them instead, and compares the 300 Whisper with the 300 AAC BLACKOUT, which SAAMI does standardise.
300 Whisper ballistics chart: manufacturer-published loads
These are the manufacturers’ own figures for specific loads we stock, taken from each maker’s page for the item number shown. There is no SAAMI reference for this cartridge, and each maker chose its own test barrel, so the figures should not be laid directly beside another brand’s.
Scroll the table sideways for the remaining columns.
| Load | Item no. | Bullet weight | Bullet | Muzzle velocity | Muzzle energy | Test barrel |
|---|---|---|---|---|---|---|
| Hornady V-MAX | 8089 | 110 gr | V-MAX | 2,375 fps | Not published | Not published |
| Hornady A-MAX | 80892 | 208 gr | A-MAX | 1,020 fps | Not published | Not published |
What the numbers mean for a shot
The 2 loads charted above, from Hornady, run from 110 to 208 grains, with published muzzle velocities of 1,020 to 2,375 fps. Each maker fired its load in its own test barrel, so a difference between two brands can come from the barrel as well as the load.
None of this is SAAMI data. Each product in our 300 Whisper ammo range lists whatever its maker publishes for that item.
Chamber and pressure
This page states no SAAMI pressure limit for the 300 Whisper. Fire 300 Whisper ammunition only in a firearm chambered for it, and follow both the ammunition maker’s and the firearm maker’s instructions. Several unrelated cartridges share a number, so match the full designation on the box to the marking on your barrel.
300 Whisper vs 300 Blackout: what the data supports
A like-for-like comparison needs both cartridges measured the same way. SAAMI standardises the 300 AAC BLACKOUT, so its figures come from one standard test barrel. The 300 Whisper has no SAAMI figures, so its numbers come from individual makers and their own barrels. The table sets them side by side with the source of each figure stated, and should be read that way.
Scroll the table sideways for the remaining columns.
| Specification | 300 Whisper | 300 AAC BLACKOUT |
|---|---|---|
| Listed by SAAMI | No | Yes |
| Maximum average pressure | Not published by SAAMI | 55,000 psi (SAAMI) |
| Bullet weights | 110 to 208 gr (loads we stock) | 90 to 220 gr (SAAMI reference loads) |
| Muzzle velocity | 1,020–2,375 fps (manufacturer-published, each in its own barrel) | 1,020–2,500 fps (SAAMI reference, 16.000 in test barrel) |
| Muzzle energy | Not published by these makers | 456–1,420 ft-lb (computed from SAAMI velocity) |
What this cannot settle is which cartridge is more powerful in your rifle: the two columns come from different sources and different barrels. We stock the other side of this comparison too: 300 Blackout ammo.
300 Whisper ballistics questions
Does SAAMI standardise the 300 Whisper?
No. SAAMI’s rifle, handgun and rimfire standards do not list the 300 Whisper, so there is no SAAMI maximum pressure, reference velocity or test barrel for it. The figures on this page are the ones each maker publishes for its own loads.
What muzzle velocity do manufacturers publish for the 300 Whisper?
For the 2 loads we stock from Hornady, the makers publish muzzle velocities from 1,020 to 2,375 fps, for bullet weights from 110 to 208 grains. Each maker measured its own load in its own test barrel, so these are not reference figures and are not directly comparable between brands.
Is the 300 Whisper more powerful than the 300 AAC BLACKOUT?
The two cannot be compared like for like, because SAAMI publishes reference data for the 300 AAC BLACKOUT but not for the 300 Whisper, and the makers of the 300 Whisper loads we stock publish no muzzle energy. The 2 loads charted publish muzzle velocities of 1,020 to 2,375 fps, against SAAMI reference velocities of 1,020 to 2,500 fps for the 300 AAC BLACKOUT.
What is the effective range of the 300 Whisper?
Effective range is not a published specification for the cartridge; it depends on the bullet, the load and the shooter. Where a maker publishes downrange velocity and energy for a load, the tables above show it, and only out to the last range that maker publishes.
How much does the 300 Whisper drop?
None of the makers of the loads we stock publishes a trajectory table for them, so this page gives no drop figure. Drop depends on the bullet’s ballistic coefficient and on the zero range, so use the figure a maker prints for the specific load.
Where to buy these loads
Hilltop Armory carries 300 Whisper ammunition from CorBon, Black Hills Ammunition and Hornady. Browse the full 300 Whisper ammo range.
