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SSK Industries 300 Whisper AR-15, $1300

When J.D. Jones, owner and proprietor of Ohio-based SSK Industries, (www.SSKIndustries.com), was approached to develop a subsonic rifle round that would excel when fired through a suppressed barrel, they knew who they were dealing with. Jones is a well-known steel silhouette shooter, ballistic pioneer, and founder of Handgun Hunters International. The idea of a subsonic round for suppressed fire was not new. But it was Jones who raised the bar and insisted that the round be fully viable in the M16 platform for full auto, semi-automatic, and even single-shot manual cycling. His invention was the 300 Whisper, which fired 30-caliber bullets weighing as much as 240 grains from a modification of the 221 Fireball case. Today, the Whisper series of cartridges range from 22 to 50 caliber, but 300 Whisper was the first iteration. Fresh brass rather than reformed cases from other calibers, reloading dies, and a variety of bullets are now available from SSK Industries.

The subject of this evaluation is a gas-impingement AR-15 carbine chambered for 300 Whisper. Our test carbine worked off a standard DPMS lower with fixed stock and 6-pound production-grade single-stage trigger. The receiver was marked “.223-5.56 model A-15” and there was a forward bolt assist on the right-hand side. Our test gun utilized a 1:7.5-inch twist 16.5-inch stainless-steel heavy barrel that was not threaded nor was a flash hider or other muzzle attachment in place. The receiver featured a Picatinny rail, and no front sight was supplied. The fore end consisted of a free-float aluminum tube with a cutout to provide access to the gas valve. The valve was marked L for low-velocity ammunition and H for high-velocity rounds. Our test gun was the base model. Adding a match-grade barrel and Gold Match trigger would bring cost to about $1800 with a few options in between. Uppers are also available separately, priced at $900 for the standard barrel. Add $200 more for a match grade barrel but deduct about $150 if you can provide your own bolt and bolt carrier. The SSK suppressor costs $650 installed. Build time for a complete gun is currently estimated at 3 to 4 weeks.

If you failed to see the unobtrusive gas port adjustment, the SSK Industries 300 Whisper AR-15 appeared to be nothing special. Once we had the chance to fire the 300 Whisper, we realized that it was at least two weapons in one, or maybe two cartridges in one. With the 208-grain Hornady ammunition, the sensation was more like firing an air rifle. Our rifle was not suppressed or silenced, but we could estimate the effect by the stunted level of noise coming through our hearing protection. We were actually more aware of the recoil buffer spring than the blast itself. This round was measured by our chronograph to be moving at 1022 fps on average. From the 50-yard bench we printed groups measuring between 0.6 and 0.8 inch across. We had a similar experience shooting the Cor-Bon 220-grain rounds. Average velocity was about 1044 fps and accuracy was identical, except for one lowly 1.0 inch group. Both of these rounds were fired with the gas valve in the “L” low-velocity position. We happened to have a large screwdriver with us, but a coin was all that was needed to turn the gas valve into position. We think a screwdriver was the better tool because the valve must be fully seated to provide the desired amount of gas. In terms of cycling we never had any difficulty or malfunction. But we did have trouble getting the bolt to lock back. According to the manufacturer, this could be caused by a short stroke or a worn magazine. SSK Industries recommends Tango Down and MagPul PMags. Ours arrived with a 20-round MagPul. We tried replacing it with another MagPul PMag, and that cured the problem. But we had to take care to seat the magazine properly.

With our gas valve turned to the high-velocity position, we fired the Cor-Bon 125-grain and Hornady 110-grain rounds. Average velocity was 2119 fps for the Cor-Bon rounds and 2345 fps for the Hornady bullets. We should note that according to our chronograph, each of our four factory test rounds produced an average velocity within a few feet per second of the velocity printed on the box. This was a rare treat. Five-shot groups firing the Hornady 110-grain ammunition measured about 0.5 to 1.3 inches across. But the Cor-Bon 125-grain rounds topped our factory rounds, producing five-shot groups that varied as little as 0.4 to 0.7 inches across.

We also fired a handload supplied by J.D. Jones himself. The bullet was a Hornady 169-grain hollowpoint boattail. Velocity was 1898 fps on average, and we managed groups that ranged in size from 0.55 inches to just less than 1.0 inch across. For this load we used the high-velocity setting. But aside from the dedicated subsonic ammunition, choice of the high and low settings could in some cases be left up to the shooter. This became more obvious during our rapid-fire sessions. Since the gun cycled properly on both the high and low settings, we could, in effect, adjust bolt velocity. Lower- or medium-velocity rounds fired with the setting at “H” would slow down the bolt. In turn this would have the effect of reducing muzzle flip or felt recoil just by reducing the sense of inertia as the bolt changed direction. Tuning handloads against the judicious use of the gas valve and an effective compensator could make for a very-flat-shooting 30-caliber rifle.

We asked J.D. about the performance of the 300 Whisper in a bolt-action gun. The only limitation that he can identify is that rifles with a Mauser-style extractor work best. But the SSK AR-15 can also be fired one shot at a time without the bolt cycling automatically after each shot. By turning the gas adjustment screw to a position in between low and high, the gas system was essentially blocked. Cycling was performed manually.

Since our SSK AR-15 was capable of greater accuracy than our other carbines, we shot some groups from the 200-yard bench. We chose the 110-grain Hornady rounds primarily because they moved the fastest, and we thought they would maintain stability longer than the others. For this shoot we visited American Shooting Centers in Houston’s George Bush Park. We set our windage to deal with the 12-mph wind, which was blowing at one-half to full value without letup. The wind didn’t seem to have as much effect on the bullet’s path as we had expected, and the results were five-shot groups ranging from about 2.1 inches to 2.6 inches across.

Our Team Said: The 300 Whisper will allow you to put a 30-caliber bullet downrange with less effort, noise, and recoil than that of a 223 round. Firing subsonic ammunition, it was hard to believe the lack of recoil, yet the same gun could be used to fire rounds producing more than 1300 ft.-lbs. of energy. Realizing we were shooting a base model gun made us appreciate the combination even more. In terms of handling we would ask the maker to pay careful attention to magazine service so insertion and charging the weapon worked as smoothly as the rest of the gun.