30-Caliber Carbines: SSKs 300 Whisper Speaks Volumes

The SSK, based on the AR-15, was effectively two guns in one. The Colorado Shooting Sports AK-47 Gen 2 updates a warhorse, but Rugers Mini-Thirty could use a better stock, we thought.


Despite the long-standing availability of the AR-10, 30-caliber semi-automatic rifles continue to be less popular than the 5.56mm/223 Rem. AR-15 little brother. But just like the high-capacity 9mm pistol led to the popularity of more powerful high-capacity handguns, we’re still interested in finding a good 30-cal carbine.

Our latest acquisitions in this quest began with Ruger’s newest 7.62x39mm Mini-Thirty carbine, the $921 No. 5854. We wanted to see if shortening the barrel to a hair over 16 inches would make it a better choice. For the AK-47 adherents, we added a $1270 Colorado Shooting Sports Custom Combat Gen 2 AK-47 that featured the addition of a Lightning Bolt and Lightning Lever for improved combat readiness. Our third gun chambered the 300 Whisper, a round designed to be fired through a suppressor. Built by SSK Industries, this was a $1300 AR-15 platform capable of shooting both high-velocity and subsonic velocity rounds with the twist of a screw in the handguard.

300 Whisper AR-15 carbine from SSK Industries

Since our primary interest was close quarters battle, our accuracy tests were limited to benchrest shooting from the 50-yard line. But we also challenged the SSK Industries 300 Whisper to longer distances to learn more about this cartridge.

In addition, we had some very specific questions to answer that had more to do with the general “shootability” of these carbines, including rapid fire. We got some help practicing for shots of record from a couple of new products from Battenfeld Technologies.

They were Caldwell’s $130 Dead Shot Field Pod and the $170 Magnum Rifle Gong. The Field Pod is an ultra lightweight collapsible shooting rest with a carry sling. We especially liked the gong because its frame broke down to 5 easy-to-carry pieces plus the durable AR550 steel plate. Ringing the gong gave our test evaluators immediate feedback and we didn’t have to paste up targets. It was a lot of fun for our testers, too.

For optics we mounted the same Springfield Armory 3-9X40mm A.R.T. IV variable power scope on both the Ruger and SSK Industries carbines. The Colorado Shooting Sports AK-47 utilized a forward mount with an Aimpoint CompML2 with 4-MOA red dot mounted and sighted in by CSS. It seemed ideally suited to the weapon and was a better choice than any long-relief scope we could supply. In view of our relatively short test distance, we chose to leave it in place.

For ammunition we utilized four different rounds of 7.62x39mm ammunition. They were 124-grain soft point Wolf Military Classic, 124-grain FMJ American Eagle, Remington UMC 123-grain Metal Case, and Winchester 123-grain full-metal-jacket rounds. Our 300 Whisper ammunition consisted of three Cor-Bon rounds and three Hornady rounds. The Hornady rounds were the 110-grain VMax, 208-grain AMax, plus a handload topped with a Hornady 169-grain hollowpoint boattail bullet. The Cor-Bon rounds were 125-grain jacketed hollowpoint rounds, 220-grain Subsonic rounds and a 150-grain jacketed soft point. Unfortunately, we had difficulty chambering the 150-grain JSP rounds and returned them to Cor-Bon for analysis.

Here’s how our 7.62x39mm and 300 Whisper competitors performed when we took them to the range:

Ruger Mini Thirty M-30/20GBCPC No. 5854 7.62X39mm, $921

The last Ruger Mini Thirty chambered for 7.62x39mm we tested was the No. 5853 model in the July 2010 issue. That gun fired from an 18.5-inch barrel and had a stainless-steel barreled action and black synthetic stock. Our current test carbine had a blued finish and the same stock with identical 13.0-inch length of pull. We hoped the shorter 16.12-inch-long threaded barrel fit with a flash hider would be more accurate, have better recoil control, and be faster handling.

Our carbine arrived with one 20-round magazine. The basic action of all Mini Thirties is the same, utilizing a breechbolt locking design with a fixed-piston gas system. The receiver is a cast part that is then machined to the proper tolerances. The bolt handle was on the right side. The bolt stop consisted of a button or rod located on the upper face of the receiver just left of the ejection port. Push it down and the bolt stays back. The bolt also locked open on an empty magazine. But the only way to release the bolt was by pulling on the bolt handle.

The safety was controlled by the trigger finger. Once the action is cocked, the operator could reach forward of the trigger guard and pull the safety rearward until about two thirds of the sheet-metal tab was inside the trigger guard. The trigger finger released the safety from inside the guard by pushing it away from the trigger. The magazine release consisted of a lever that extended downward from behind the magazine well. Grabbing the magazine on the forward edge, the thumb naturally finds the release, making its operation ambidextrous. Pressing the lever forward without gripping the magazine body allowed the magazine to drop free.

The forend was clamped hard onto the barrel at the front with four screws. There were eight vent holes measuring about 0.4 inch in diameter just rearward of the clamp which also included a sling loop. There was a matching sling loop beneath the buttstock, which was capped with a rubber pad. The pistol grip was quite thin. The Mini 14 Tactical rifle, essentially the same as the Thirty but chambered for 223 Rem., is available with an AR-15/style adjustable buttstock and vertical pistol grip. Perhaps AR-15 stocks are in the future of the Mini Thirty as well—which we hope for. Until then, the Ruger shop offers SAW-style tactical stocks for the Mini-Thirty by ATI and Tapco. Hogue overmolded rifle stocks that offer pillar bedding is another alternative available from Ruger.

The top of the receiver offered Ruger’s integral scope mount and supplied matching 1-inch rings. The rear-sight unit was located behind the rear mount and alongside the charging handle. The supplied sights consisted of a ghost ring in the rear and a ramp-style blade up front. The front sight, the two ears that protected it, and the band was one solid piece roll-pinned to the barrel. The rear unit was held to the receiver by an Allen screw. Adjustment for windage was achieved using a sort of push-pull action loosening and taking up slack on the two locking set screws located on either side of the rear sight. Using a 5/64-inch hex wrench, we loosened the set screw on the side corresponding with the desired direction of movement first. Then we locked in the position by tightening the opposite set screw. There were no reference clicks. The only calibration offered was found in the owner’s manual amounting to, “One full rotation of the hex screw will move the point of impact approximately 5 inches at 100 yards.” To change elevation requires that you first loosen one of the set screws (the manual recommended one full turn) and rotate the aperture clockwise for down and counter-clockwise for up. One half-turn, swapping the front of the aperture to face the rear will, according to the manual, change elevation about 1.25 inches at 100 yards.

We encountered difficulties we did not experience during our earlier test of the longer barreled Mini-Thirty in 2010. We found the magazine more difficult to fill with rounds and load into the receiver. When chambering a round, we had to press upward on the base of the magazine to make sure a round went home every time — especially when we began with the magazine inserted and bolt closed. At one point we noticed the base plate that seals the bottom of the magazine was backing off and in danger of releasing its payload. Otherwise, we didn’t have any malfunctions of any kind during this test.

From the 50-yard bench we noticed that our first choice of ammunition, the 124-grain Wolf Military Classic rounds, were the least accurate. Of note was a decidedly low first shot. After studying our results, we noticed that the rounds we fired during the middle of our session appeared to be more accurate. Average five-shot groups in order of fire were the Wolf, 1.6 inches; Remington, 0.9 inches; Winchester, 0.6 inches; and American Eagle, 1.3 inches. Perhaps the Mini-Thirty simply liked a certain amount of heat and no more. We decided to retest the Mini-Thirty firing only the Winchester 123-grain FMJ rounds that soundly outperformed the other ammunition. But this time we fired three groups of five rounds from a cold bore. Each group showed one shot low and a four-shot group above, which averaged about 1.5 inches across. We think this shows that the Ruger Mini Thirty was affected more by barrel temperature than a given type of ammunition. The reason for this could be the solid contact made with the stock, especially at the forend. The barrel could be heating up and “pushing” against the stock, changing the point of impact.

In terms of rapid fire, the cycling and bolt impulse might have felt slow and heavy, but we could only say for sure that shooter prep and follow through demanded strict attention. Certainly the takeup and travel of the 7.5-pound trigger demanded a rigid and precise mount, but we thought the stock was a little too straight and slippery. One comment was that it felt like we were trying to fire semi-automatic from a bolt-action stock. We think a wider buttstock with more pistol grip would help the shooter on both these counts.

Our Team Said: As reliable as the Mini Thirty was, we think loading and general handling would be faster and easier with better-quality magazines. The shorter barrel did make the gun feel more maneuverable despite the minimal difference in overall length. We’d like to try this gun with another stock for an improved mount and perhaps less deflection from barrel temperature. Also, simply replacing the flash hider with an effective compensator might go a long way toward making this carbine a more viable option for CQB.

SSK Industries 300 Whisper AR-15, $1300

When J.D. Jones, owner and proprietor of Ohio-based SSK Industrieswas 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.

Colorado Shooting Sports Custom Combat AK-47 Gen 2 7.62X39mm, $1270 as tested

Based on recent sales figures, the AR-15 is undoubtedly America’s favorite rifle. That it is standard issue to our military and continues to be the target of anti-gun politicians and activists has made the AR-15 not only a hero’s weapon but a symbol of freedom. The AK-47, on the other hand, has not had the same favorable press. One look at a photograph of an AK-47 in the hands of the flinching and now deceased Osama bin Laden can be enough to dampen its appeal.

But the AK-47 is gaining in popularity based on respect for its reliability and formidable capability at close to moderate distances. As such, we are beginning to see growth in the availability of Americanized AK-47s. By Americanized we mean with modifications based on American ingenuity, a term we used to hear more often. One such AK is the Colorado Shooting Sports Custom Combat AK-47 Gen 2.

Our CSS AK-47 Gen 2 was based on a Saiga product, but the conversion can be applied to just about any AK-47 or AK-74. Our AK had a folding stock, but the price for both folding and fixed stock models is the same. Optional equipment was the $120 Ultimax scope mount and the $150 XS sights. The base price of $999 applies to an AK-47 tuned by Colorado Shooting Sports and fit with a couple of upgrades that makes the AK platform even more battle-worthy, if not simply more enjoyable to use. The Lightning lever and the Lightning bolt upgrades sell for $65 and $250 respectively. The Lightning lever allows the shooter to work the safety without any change from the shooting grip. So many times we’ve seen safeties on a variety of weapons that are so awkward or tight they go unused. The Colorado Shooting Sports website says the Lightning lever is designed to “Reinforce proper gun handling.” What we liked even more was the Lightning bolt. Smoothing and slightly reducing the mass of an AK bolt is not necessarily a new modification. But the $250 CSS Lightning bolt adds a bolt handle to the left side, so charging is ambidextrous. Making reloads and charging the gun proved faster and easier with the Lightning bolt in place, our team said.

Each of our test guns had at least 200 rounds fired through them. But we probably put more rapid-fire rounds through the CSS AK-47 than either of our other two guns, primarily because it was so much fun. Our test gun had a natural forward bias to it since much of the action was located well ahead of the grip. With the application of a $49 AK-47 style muzzle brake, we can’t claim it shot absolutely flat, but tracking the rise and return of the red-dot sight told us that we could get back on to target pretty quickly. No malfunctions occurred during our tests, and that leads to another impression we had of this carbine. Each of our testers has shot numerous competitions, and the natural instinct regarding the weapons was to clean them at every opportunity. We felt no such compulsion to service the AK-47 at any time.

The folding stock was rigid, and once locked in place it seemed just as strong as a fixed stock. It unlocked easily by pushing the button on the left side, but it did hang up on the left-side bolt handle. Naturally, this prevented us from firing with the stock folded. We didn’t want the bolt handle to double as a retention point, but the parts were so rugged we don’t think it will cause a problem. The Ultimax scope mount was about 6.6 inches long and offered a total of 16 slots. The mount followed the top line of the receiver so closely it looked like part of the original design. With the Aimpoint removed, we noticed that the elevation screw on our rear sight was missing, but we were spot-on out to 50 yards so we didn’t bother to replace it. The XS big dot in conjunction with the sloping style rear notch was very easy to follow. The rear notch was drift adjustable for windage. We think this combination maximized the available 12.3 inches of sight radius.

Magazine insertion was clean and true. The magazine release was performed by the thumb as you gripped the magazine body. Simply hitting the release would not allow the magazine to drop free, so it had to be pulled from receiver. The stroke of the 4-pound trigger consisted of a smooth, arcing takeup with a sudden release that was not preceded by any sudden point of resistance.

In terms of power we noticed that our AK-47 produced less velocity than the Ruger Mini-Thirty, about 100 fps on average. Some tolerances found in the AK-47 are typically more forgiving so it can shoot reliably with a wider variety of ammunition. Another component of its reliability was probably the steel magazine, which was hammerlike compared to the AR and Mini-Thirty mags. Five-shot groups from the 50-yard bench firing the Wolf and Remington rounds measured about 1.6 inches and 1.4 inches respectively. The American Eagle rounds were better, averaging about 1.2 inches. Considering we had to accommodate a 30-round curved magazine in our setup, a best group measuring 0.6 inches across firing the Winchester ammunition was pretty good. The average size group computed to about 1.0 inch. We might also credit the clarity of the 1X magnification Aimpoint red dot scope.

Our Team Said: The CSS AK-47 Gen 2 was fun to shoot, as maintenance free as we could hope for, and surprisingly accurate. In our view the addition of the Lightning bolt and Lightning lever made the AK-47 more shooter friendly. If the stigma of a Soviet Bloc weapon and the lack of a domestic manufacturer is preventing wider acceptance, we think the ongoing attention of innovators such as Colorado Shooting Sports will continue to foster the acceptance of the AK-47 by the American gun buying public.









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