The Doublestar Corporation 300 Blackout

By Christopher R. Bartocci

The AR-15 platform is the most diverse weapons platform in the world. No other weapon system has the modularity and ability to change out cartridges. The platform has been chambered in many cartridges including .204 Ruger, 5.45x39mm, .22 Long Rifle, 5.7x28mm, .222 Rem., .223 Rem./5.56mm, 6.5 Grendel, 6.8mm SPC, 7.62x39mm, 7.62x45mm Wilson, .30 Rem. AR, .499 LWRC, .458 SOCOM and .50 Beowulf – to name a few. The primary cartridge remains the long serving 5.56mm. However, a new cartridge has appeared on the scene that is ready to take number 2 in popularity and that is the 300 Blackout, giving the shooter 7.62x39mm ballistics plus 10%. This round requires no modifications to the rifle but the barrel. Standard magazines are used giving the full capacity of the magazine. Due to the shape of the cartridge case, the cartridges sit properly in the magazine unlike the 7.62x39mm cartridge with the extreme taper, which has prevented a reliable 30-round magazine from being developed using the standard AR mag well.

More than 200 companies as of this writing make products to support this caliber. SAR was given the opportunity to test one of the newer rifles on the market, the DoubleStar Star-15 chambered in 300 Blackout. The rifle was introduced in the summer of 2012 with an MSRP of $1,029.99. DoubleStar has been in business since 2000 and started as J&T Distributing in 1980 selling parts and accessories. Of the rifles produced by DoubleStar, their most popular rifle remains the StarCar, DS4 and C3.

The rifle as received utilizes a 16-inch heavy barrel with a black nitride finish. The rifle was tipped with a Yankee Hill Phantom flash suppressor. There was a low profile gas block, which was held in place by locking bolts rather than pinned in place. The top of the gas block has a rail section of Mil-Std 1913 rail on top of it. The rifle used a standard carbine length gas system and was equipped with single heat shield handguards.

The upper receiver is made of 7075 T6 aircraft aluminum and has a forward assist assembly, fired cartridge case deflector and ejection port cover. Top of the rail has a Mil-Std 1913 rail. This is a standard M4-type upper receiver and the charging handle is a standard M4-type charging handle.

Due to the characteristics of the 300 Blackout cartridge a standard M4-type bolt carrier group is used. This particular carrier was a semi-auto only carrier with the sear trip area cut back. The bolt carrier had a properly staked gas key and was finished with the Mil-Spec manganese phosphate finish. The bolt was a standard bolt and the extractor was equipped with a rubber “o” ring that slides over the extractor spring greatly enhancing the extractor force lessening the probability of having the extractor slip off the rim during extraction and ejection.

The lower receiver is also manufactured from 7075-T6 aircraft aluminum. The stock is a standard military style polymer stock with the DoubleStar logo on it. The receiver extension offers six different positions. The rifle used a standard carbine buffer as well. The trigger group is a standard single stage factory trigger. It is this author’s opinion for any combat style rifle this is the optimal type of trigger. This trigger broke at 7 1/4 pounds. The standard A2 style pistol grip was used.

The rifle was provided with one C Products Defense aluminum magazine with an orange anti-tilt follower. This company, formally C Products of Connecticut, was purchased and moved to Florida under new management. The magazines are quite different from the Connecticut made magazines; many improvements have been made to the entire line and some of the magazines have been redesigned entirely. This rifle was test fired with a variety of other magazines including the 3rd generation PMag, Lancer AWM, H&K magazine as well as a standard GI aluminum magazine.

Just in time to test this rifle, a brand new EOTech 300 Blackout optic was received. This optic is designed specifically for the 300 Blackout cartridge. The 300 Blackout model XPS2 1x holographic sight offers two 1 MOA aiming dots that provide precise points of aim throughout the effective range of the round. The 300 Blackout ammunition is offered in both sub and supersonic loads. To switch back and forth, the shooter will need to re-zero but the engraved reticle image on the hood of the sight provides simple reference points. Using the 16 inch barrel of the DoubleStar carbine and a 110 grain supersonic projectile, the top dot of the sight should be zeroed at 100 yards. At this zero distance the second dot will be zeroed at 300 yards. When using the 220 grain subsonic ammunition, the top dot should be zeroed at 50 yards. At this distance the second aiming dot will be zeroed at 250 yards. The sight is powered by a single CR123 battery that will run continuous for 600 hours set on 12. There are 20 different brightness settings of the dots. The intensity is adjustable by pressing the up and down switch on the rear of the sight. To turn the power on, press one of the buttons and to turn off, push both at once. The temperature range of the sight is from -40 to 150°F.

Also just received is the new Otis Technology 300 Blackout cleaning system. Built on their proven “breech to muzzle” cleaning system, this new kit offers every tool necessary to properly maintain a rifle in the new caliber. The kit includes the cable along with chamber brush, bore brush, slotted tip (patch holder) two cleaning picks (for reaching hard to get areas), breech face scraper, nylon all purpose brush, cleaning oil, lens brush, lens cleaner and Q-tips. Additionally, the kit is equipped with a .30 caliber Mongoose brush, which is a bore brush with the top half being a wool mop for quick cleaning in the field. The chamber brush is specifically designed to properly clean the 300 Blackout chamber and barrel extension. All of this fits in a small round package that fits in the palm of your hand. Otis Technology is known to be the premier weapons cleaning system in the world and has been the main cleaning equipment contractor for the U.S. military for many years.

The rifle was test fired with a wide range of 300 Blackout ammunition in both super and subsonic loads. It should be noted that the rifle did not fully cycle with any of the subsonic cartridges. The rifle is designed to have a sound suppressor on when firing this ammunition. When firing this ammunition with a suppressor on, the overpressure conditions caused by the suppressor offer enough chamber and port pressure to cycle the rifle completely. The rifle functioned flawlessly with all of the supersonic ammunition that was fired. The supersonic ammunition included the Barnes 110 grain TAC-TX, Hornady 300 Whisper 110 grain V-Max, Remington UMC 115 grain CTFB and Remington 125 grain AccuTip. For subsonic loads, Remington 300 Blackout 220 grain OTM and Hornady 300 Whisper 208 grain AMAX was used. Groups averaged between 1.5 and 2 inches at 100 yards with the entire variety of ammunition. More than 200 rounds of supersonic ammunition were fired with no malfunctions. Recoil was noticeably more than a 5.56mm but still very easy to control. Quite pleasant considering the recoil of an AK47 firing the comparable 7.62x39mm cartridge. The optic worked just as advertised and if you are dedicating an optic just for the 300 Blackout cartridge the EOTech sight is just what you need.

The 300 Blackout cartridge is certainly here to stay. The cartridge has bridged the gap for those who like the power of the 7.62x39mm cartridge but do not like the AK-type rifle. The DoubleStar rifle is an excellent rifle to fire this cartridge. When using supersonic ammunition, the rifle is reliable and accurate. Keep in mind if you want to fire subsonic ammunition, you will need the sound suppressor to get the rifle to function reliably. The OTIS 300 Blackout cleaning system holds everything needed to properly maintain the rifle. It would be safe to assume there will be more models of this caliber coming out in the future.

This article first appeared in Small Arms Review V18N2 (April 2014)
and was posted online on January 17, 2014


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