The Ruger Mini-14 and Its Cartridges

The overall length of the Mini-14 Tactical Rifle in 300 Blackout is 36.25 inches, and adding a Nosler SR-30ALTi suppressor increases that to a very maneuverable 42.5 inches. Fresh from its factory box, it weighs 6.7 pounds; adding the suppressor, an Ultradot sight, and 20 rounds in its steel magazine increases that to an ounce less than nine pounds.

I first shot a Ruger Mini-14 in August of 1978 in Rhodesia. Professional hunter John Tolmay was at the airport in Salisbury when I arrived. From there, we flew to the small village of Kariba then took a very long boat ride across Lake Kariba to Bumi Hills Lodge, which was located on a tall hill overlooking the lake. Despite the fact that a bush war with Communist-backed terrorists had been ongoing for about 10 years, we were intent on hunting buffalo.

John carried a Ruger Model 77 in 458 Winchester Magnum but a Ruger Mini-14 in the hands of his most trusted tracker was always within quick and easy reach. How did he get the little rifle only four years or so after it went into production at Ruger? John served in the Rhodesian Security Forces, and Ruger Model AC-556 rifles purchased by his government could be fired in semiautomatic mode, 3-round bursts or fully automatic. The rifle issued to him had an 18-inch barrel and two taped-together, 30-round magazines.

A Swarovski 3-9x scope was used on the Mini-14 when accuracy testing for this report but as shown here, it usually wears an Ultradot with a one-inch tube. When shooting from a benchrest, the rifle was supported by a Caldwell rabbit ear bag filled with sand at the rear and a Lyman Match Bag resting on that company’s quick elevation-adjustable Bag Jack at the front. An extremely effective Nosler SR-30ALTi suppressor was also used.

After I had taken a very good bull with a Browning Safari Grade rifle in 375 H&H, we returned to Kariba. We boarded Air Rhodesia Flight 825 back to Salisbury and then went on to 10 days of hunting Sable, Greater Kudu and various other antelope with a custom rifle in 7mm-08 Improved. I will never forget that flight number. A week or so after returning home, I was informed that Flight 825 had been downed by a Soviet-supplied, SA-7 heat-seeking missile as it was gaining altitude a few miles out of Kariba. Eighteen passengers survived the crash, but only eight managed to avoid being slaughtered by guerrillas armed with AK-47 rifles.

Hornady offers two subsonic loadings of the 300 Blackout, one with a 190-grain SUB-X bullet at 1,050 fps, the other a 208-grain A-MAX at 1,020 fps. The V-MAX does not expand at subsonic velocity. The Lehigh Defense load has a 194-grain Maximum Expansion bullet at 1,050 fps, and it is constructed specifically to expand violently at subsonic speed. Cartridges include: (1) 190-grain Hornady SUB-X, (2) 194-grain Lehigh Defense Maximum Expansion and (3) 208-grain Hornady A-MAX.

In addition to becoming quite popular in the United States, the Mini-14 has been adopted by a number of other countries for use by military and/or law enforcement. They include France, United Arab Emirates, Indonesia, Brazil, El Salvador, Australia and Argentina. Perhaps the oddest was a straight-pull version purchased by Great Britain, where law-enforcement agencies are not allowed to have semi-automatic rifles. For a while, Ruger built the Mini-14 in 222 Remington for civilian shooters in countries that do not allow ownership of rifles chambered for military cartridges. The 6.8mm Special Purpose Cartridge (SPC), jointly developed by Remington and members of the U.S. Special Operations Command, was another short-lived chambering. Just as Clint Eastwood, portraying detective Dirty Harry, introduced the Smith & Wesson Model 29 revolver in 44 Magnum to millions of moviegoers, so it went for the Ruger Mini-14 as large television audiences tuned in each week to watch actor George Peppard as Colonel John “Hannibal” Smith and the rest of The A-Team crew end the careers of bad guys.

With a soft lead core housed in a thin jacket with deep skiving along with a Flex-Tip insert in its hollow nose, the 190-grain Hornady SUB-X bullet is designed to expand at an impact velocity as low as 900 fps. It has a .437 ballistic coefficient, so with a launch velocity of 1,050 fps, expansion should be quite good out to the far side of 50 yards. According to Hornady, construction of the SUB-X bullet meets FBI protocol for terminal ballistic test requirements.

The Mini-14 has been available in both 223 Remington and 5.56 NATO but is now available only in the latter chambering. As most experienced shooters should know, the 223 can be safely fired in the 5.56x45mm chamber but, conversely, is not recommended. The 7.62x39mm Russian addition prompted a Model designation change to Mini-30 (also known as Mini Thirty), which is still available. It might be of interest to note that the barrels of those rifles have had two different groove diameters. The one I wrote about 30 years or so ago measured .308-inch but a forcing cone-shaped throat of its chamber allowed the safe use of bullets as large as .311 inch which is standard in military ammunition. Hornady still makes the .310-inch, 123-grain Inter-Lock SP bullets I shot in that rifle. Ruger eventually changed the groove diameter to a nominal .310-inch and there it remains to this day. Like Mini-14s in other calibers I shot in those days, groups fired by that one at 100 yards were in the neighborhood of four inches with an inch less being cause for celebration. After the rifle was given a heavier barrel in 2008, group size was considerably reduced, with minute-of-angle accuracy delivered often enough to be more than accidental.

The 2015 addition of the 300 Blackout option to the Mini-14 Tactical Rifle eventually resulted in a huge increase in sales, and today, it rivals the 5.56 NATO in popularity. A change in the gas port ensured reliable functioning with both supersonic and subsonic ammunition so long as a sound suppressor is used with the latter. The 16.12-inch barrel with its 1:7 twist has 5⁄8x24 threads at the muzzle, and it comes with a flash suppressor attached. The stock is made of rugged glass-reinforced nylon. Also included are two 20-round magazines, a pair of one-inch scope mounting rings for the grooved receiver and a short Picatinny rail. Magazines holding 5, 10 and 30 rounds are available. The overall length of the Mini-14 is 36.25 inches and adding a Nosler SR-30ALTi suppressor increases that to a still maneuverable 42.50 inches. Fresh from its factory box, it weighs 6.7 pounds, and adding the suppressor, an Ultradot sight and 20 rounds in the steel magazine increases that to an ounce shy of nine pounds.

The Mini-14 in 300 Blackout has 7⁄8x24 threads at the muzzle and comes with a flash suppressor attached. Ruger designed the rifle for attachment of a sound suppressor, and when subsonic loads are used it usually will not cycle without one. The rifle works perfectly with or without a suppressor when supersonic loads are used.

For those who do not know, the 300 BLK under a different name was created by J.D. Jones of SSK Industries in 1992. Attaching an efficient suppressor to the barrel of a rifle does not eliminate that noise entirely, but it is considerably reduced. The small sonic boom created by the bullet as it exceeds the speed of sound is eliminated by keeping its exit velocity in the neighborhood of 1,050 feet per second (fps). The 300 Whisper, as J.D. called it, was formed by necking up the 221 Remington Fireball case, and it was intended for use by law enforcement and the military in the AR-15/M16 rifle. Converting one of those rifles was no more difficult than switching barrels.

The 300 Whisper was commonly loaded with match-grade, high ballistic-coefficient bullets weighing from 220 to 240 grains at a nominal velocity of 1,040 fps. Upon impacting soft targets, they did not expand, but their larger diameter made them more effective than .22-caliber, full-metal-jacketed bullets fired from the 5.56 NATO cartridge. As J.D. Jones described it to me, the 300 Whisper was an easy way for members of law enforcement and the military to improve the stopping power of the AR-15/M16 rifle. He particularly saw it as a more potent replacement for the 5.56x45mm in the M4 carbine as well as 9mm select-fire guns used by the U.S. Navy SEALS and other special operations troops. The cartridge was never intended for long-distance shooting. Jones registered his cartridge with CIP (the European equivalent of SAAMI), but he also failed to have it approved by SAAMI. That left the door of opportunity open for Advanced Armament Corporation (who changed the name of the 300 Whisper to 300 AAC Blackout) to join forces with Remington, who sponsored the cartridge with SAAMI. With the exception of their headstamps, the two cases are identical, so reloading dies made for the 300 Whisper and 300 Blackout can be used.

The all-copper, 194-grain Maximum Expansion bullet made by Lehigh Defense is 1.560 inches long with an extremely deep cavity that begins at the nose and reaches .800 inch into its body. As a final touch, the CNC Swiss screw machine that shapes it saws three narrow exterior weakening grooves spaced on 120-degree centers beginning at the nose and extending back to adjacent with the bottom of the cavity. As the bullet penetrates, it splits into three petals that radiate outward while remaining attached to the solid shank of the bullet. Designed specifically to perform at subsonic velocities, it should not be pushed faster.

One would be hard-pressed to find a better rifle for repelling castle invaders than a suppressed Mini-14 with its magazine filled with subsonic loadings of the 300 Blackout. The near lack of muzzle blast makes it much more suitable for shooting indoors than is the case for non-suppressed firearms. How quiet is it? To my ears, cycling of the Mini-14 action is louder than the muzzle report produced by the extremely small powder charge. Hornady offers subsonic ammunition loaded with a 190-grain SUB-X at a velocity rating of 1,050 fps. With a soft lead core housed in a thin jacket with deep skiving along with a Flex-Tip insert in its hollow nose, the bullet is designed to expand at an impact velocity as low as 900 fps. It has a .437 ballistic coefficient, so with a launch velocity of 1,050 fps, expansion should be quite good out to 50 yards or so. I am told that bullet performance of the SUB-X bullet meets FBI protocol for terminal ballistic test requirements. In its Black series, Hornady also offers the 208-grain V-MAX at 1,020 fps and like the bullets loaded by J.D. Jones, in his 300 Whisper three decades ago, it does not expand at subsonic impact velocities.   

When creating his 300 Whisper on the 221 Remington Fireball case about three decades ago, J.D. Jones loaded it with heavy match-grade bullets. While they did not expand at subsonic velocities, their larger diameter made them more effective than .224-inch, full-metal-jacket bullets fired from the 5.56 NATO cartridge. Those loads of yesteryear are easily duplicated in the 300 Blackout with Berger bullets.

Equally interesting is the 194-grain Maximum Expansion bullet of monolithic design made by Lehigh Defense. CNC Swiss screw machines at the Clarksville, Texas factory carve long copper rods into bullets of a specified diameter, weight and shape. Measuring 1.560 inches long, the .30-caliber, 194-grain bullet has an extremely deep cavity that begins at the nose and reaches .800 inch into the body of the bullet. As a final touch, the machine cuts three narrow exterior weakening grooves spaced on 120-degree centers beginning at the nose and extending back to adjacent with the bottom of the cavity. As the bullet penetrates, its front section splits into three thick petals that radiate outward while remaining attached to the solid shank of the bullet. Retained weight is 100 percent. Printing on the box warns against loading the Maximum Expansion bullet faster than subsonic velocity.

J.D. Jones formed his 300 Whisper by necking up the 221 Remington Fireball case for heavy, .30-caliber bullets at subsonic velocity. While this can still be done, using Starline 300 Blackout cases is easier and more readily available as well. Loading dies made years ago for the 300 Whisper work equally well for the 300 Blackout today: (1) 300 Whisper formed from 221 Fireball brass, (2) 221 Remington Fireball cartridge, (3) 300 Blackout on the Starline case and (4) Starline 300 Blackout case.

I can think of a hunting application where both bullets should really shine. Calling in coyotes in the South Eastern region of our country during daylight hours can be nearly impossible but they often are easy to coax quite close at night. Farms are often fairly small and close together, and while most stock owners absolutely despise coyotes, they do not appreciate being disturbed by gunfire at night. From a suppressed rifle, subsonic loads with the Hornady and Lehigh Defense bullets are almost as quiet as a mouse sneaking across carpet, and they would be quite deadly on coyotes called in close.

When developing a supersonic load for a rifle, it is customary to begin with a reduced powder charge and work up while keeping a close eye on pressure signs. It is just the opposite for choosing a subsonic load. Begin with a pressure-tested load from a reputable source, and if velocity proves to be a bit high, the charge is carefully reduced until reaching a velocity of 1,050 fps or close to it. With that velocity level reached, 10 rounds are slow-fired with a chronograph to confirm that bullets are actually receiving enough kick in the rump to exit the barrel. Verification can also be accomplished by shooting 10 rounds at a paper target with a pause to peep through a spotting scope between each shot.

The Mini-14 fed subsonic 300 Blackout loads with bullets of various nose profiles from its 20-round steel magazine without a single malfunction: (1) 194-grain Lehigh Defense Maximum Expansion, (2) 208-grain Hornady A-MAX and (3) 190-grain Hornady SUB-X.

Powders recommended by various sources produce low pressures at subsonic velocities. I prefer all the push on the base of a bullet I can get so when given a choice, I go with the powder that produces the highest pressure. Taking examples from Hodgdon, respective pressures for 13.0 grains of H322 (1,058 fps) and 8.3 grains of Lil’Gun (1,044 fps) behind the Hornady 190-grain SUB-X are 18,100 psi and 23,100 psi so given a choice between those two, my pick would be Lil’Gun. It is important to keep in mind that reducing a pressure-tested load too far below 1,000 fps can leave a bullet stuck in the barrel.

Attaching a suppressor to the Mini-14 can cause unpleasant gas to flow back through the barrel, out through the ejection port and into the shooter’s face as the action cycles. This is commonly referred to as blowback or over-gassing. Replacing the factory gas block with an adjustable gas block from Accuracy Systems is a popular fix, although I have yet to try it. Blowback can be worse with some powders than with others and I have indicated just that in my handloads table. The obvious winners during my tests were Lil’Gun, W-760/H-414 and A-5744. There is one other issue to consider. At the extremely low pressures generated by powders delivering subsonic velocities, propellant burn can be less than complete. Firing a round, removing the suppressor from the rifle, and vigorously shaking it over a sheet of white paper can reveal this. Some stick powders are the worst offenders.   

The Mini-14 in 222 Remington was mostly sold in countries where civilians were not allowed to own rifles chambered for a military cartridge. The 6.8mm Remington SPC chamber was also rather short lived. The rifle has also been available with 223 Remington and 5.56 NATO chambers and while the former cartridge can be safely fired in the latter chamber, conversely is not recommended. The barrels of early rifles in 7.62x39mm had a nominal .308-inch groove diameter, later changed to the present .310-inch. The 300 Blackout currently rivals the 223 Remington in sales. Cartridges include: (1) 222 Remington, (2) 223 Remington, (3) 5.56 NATO, (4) 6.8mm Remington SPC, (5) 7.62x39mm Russian and (6) 300 Blackout.

Attaching a suppressor to the Mini-14 can cause unpleasant gas to exit the ejection port and into the shooter’s face when subsonic loads are used. This is commonly referred to as blowback or over-gassing. Blowback can be worse with some powders than with others and during Layne’s tests, he found the use of these powders eliminated it entirely.

While shooting the Mini-14 for accuracy from a benchrest, it was supported at the rear by a Caldwell bunny ear bag filled with sand and at the front by a Lyman Match Bag supported by that company’s quick height-adjustable Bag Jack. The rifle usually wears an Ultradot, one of the few red dot sights still available with a one-inch tube and still a favorite among precision bullseye competitors. I switched to a Swarovski 3-9x scope during my 50-yard accuracy tests. As was expected, the little rifle gobbled up ammo loaded with bullets of various profiles without a single hitch.   

If Colonel Townsend Whelen were still with us he might say that while the Ruger Mini-14 is not accurate enough to be particularly interesting, it is accurate enough for its intended purpose and is absolutely loads of fun to shoot as well.