The 300 Blackout Ammo Blackout Subsonic Ammunition was developed specifically for accuracy and performance at velocities lower than the speed of sound. The Sub-X (Subsonic – Expanding) bullet with 190 grains of weight has a core made of lead. Because of the combination of the bullet’s flat profile, the long grooves in its gilding metal jacket, and the unique Flex Tip insert within the hollow-point cavity, the bullet is able to expand reliably even when traveling at low velocity. The performance of the 300 Blackout Subsonic load either meets or surpasses the parameters set forth by the FBI Protocol terminal ballistic test.
Brief History on .300 blackout ammo
While 5.56×45mm NATO has enjoyed widespread acceptance in military circles, the nature of the missions encountered by some special operations groups often demand a round that provides better performance than that available in the high-energy, standard velocity rounds, and subsonic performance greater than standard 9×19mm Parabellum (the ubiquitous pistol and submachine gun) round.
To meet this demand, AAC developed the .300 AAC Blackout in cooperation with Remington Defense. The new cartridge was intended to negate many of the perceived drawbacks inherent to other large caliber cartridges used in the M4. Colt Firearms and other arms makers had previously chambered AR-pattern rifles and carbines in various .30 caliber rounds but encountered problems.
In the case of the 7.62×39mm, its relatively severe case angle caused feeding issues unless specially modified AK-47 magazines were used, and even then results were unsatisfactory. Modified bolts were also needed owing to its larger case head diameter. Rounds such as the 6.8 SPC and 6.5 Grendel had similar parts-interchangeability issues but did allow for the use of the standard M4/M16 30-round magazine, albeit with a reduced capacity.
• Impact velocities of 960 to 1,020 fps into ballistic gelatin, providing 16-18” penetration and 90%+ weight retention.
• Designed to expand at velocities down to 900 fps.
• Loaded with unique powders optimized for subsonic use, the low flash signature is ideal for both suppressed and unsuppressed performance.
• Bullets feature a cannelure for a positive case crimp for use in semi-autos.
• Designed specifically to fit, feed, and function in a variety of firearms including gas system guns.
300 blackout subsonic ammo
The 300 Blackout Ammo was designed to achieve energies similar to the 7.62×39mm Soviet in an AR-15 while using standard AR magazines at their full capacity. The 7.62 Soviet’s cartridge taper prevented reliable feeding in AR magazines and created wear on the bolt. From the 14.5 in (370 mm) barrel of the M4 carbine, the M855 5.56×45mm round has an effective point target range of 500 meters. The bullet has significant drop, drift, and energy loss at that distance.
From a 16 in (410 mm) barrel, a 125 gr (8.1 g) .300 BLK round has a lower velocity and similar bullet drop and drift at shorter distances. However, it has the same amount of energy at 700 meters that the M855 has at 500 meters. In terms of hit probability, the Blackout has an effective range of 460 meters. From a 9 in (230 mm) barrel, the 125 gr BLK round has the same muzzle energy as the M855 from the M4, and 5 percent more energy at 440 meters.
In comparison with 7.62×39mm rounds, .300 BLK rounds with varying loads have better ballistic coefficients and more energy out of similar length barrels. 300 BLK rounds like the Barnes TAC 110 grain, have “barrier blind” performance, being capable of penetration through several inches of different hard targets. 300 Blackout Ammo allows a user to have one firearm with the capability of switching between subsonic, supersonic VMAX or barrier penetrating ammunition all with just the change of a magazine.
It is able to replace the H&K MP5 for close quarters, and with just a magazine change, bring the fight to longer distances, outperforming the M4 carbine.The .30 caliber cartridge has an 89.1 percent increase in frontal bullet area over the 5.56×45mm, and so leaves a larger wound cavity in soft targets. It also penetrates deeper and initially yaws faster. 300 BLK rounds are effective out of barrels as short as 4.5 in (110 mm). Weapons chambered for the round can be as light, compact, and quiet when suppressed as submachine guns like the 9×19mmMP5, 5.7x28mmFN P90, and 4.6×30mm MP7 while having more energy and accuracy at longer range.
Potential hazards of 300 aac blackout ammo
AR-15 rifle with dustcover and magazine band that identify it as having a chambering of .300 AAC Blackout
The very advantage of the subsonic 300 blackout ammo (its similarity to the popular .223/5.56 caliber) can also be a safety issue if ammunition of the two calibers is mixed. Because of similar chamber dimensions between the two calibers, SAAMI has listed the combination of using a 300 blackout ammo round in a .223 chamber as unsafe.
Since the bullet of the 300 blackout ammo is larger than the bore of the .223 caliber, chambering and firing causes excessive pressure to build up since the bullet has nowhere to go, which can cause the rifle to explode resulting in risk of injury or death. Since the mix up can easily be done, some suggest owners of firearms in both calibers carefully separate firearm and ammunition of the two types by, for instance, clearly marking the firearms and magazines, and visually inspect every round while loading magazines.
Whether a 300 blackout ammo cartridge actually is able to chamber in a .223 barrel depends on bullet length and shape, bullet seating depth, crimping, and the volume of powder charge. Ideally, cartridges would use one of the longer projectiles, a case-filling powder charge, and have the projectile crimped into place.