Robert Silvers of Advanced Armament Corp developed 300 Blackout in 2010. He wanted a round as good as 7.62×39 in supersonic form, and far better in subsonic loads which took 300 Whisper as the benchmark. Since then, supersonic loads developed only a modest following, while subsonic applications flourished. Well-suited for short barrels, 300BLK found favor with hunters, home defenders, and military users alike.
The caliber’s compatibility with 5.56×45 bolts and magazines, along with wide availability of ammunition made 300BLK logistics far easier than ballistically stronger 338 Spectre or 8.6BLK. Combine all that with good accuracy, quiet report, and mild recoil, it unseated the previous king of subsonic carbines, the big fat 45 ACP.
So, what ammo should you consider first for your 300 BLK rifle? We can help. Know years of range experience went into our top picks for 300 BLK ammo.
Best Subsonic 300 Blackout Ammo Picks
Hornady Black ELD Match 300 BLK Ammo
Hornady Black ELD Match: non-expanding 208gr precision bullet works well by tumbling up close, but makes the most sense for hard targets (like hog skulls) or very small varmints at a distance. 1MOA is a reasonable expectation. Hornady Frontier 208gr FMJ is an excellent practice load to save match bullets for serious business. Trajectory difference is negligible even at 200 yards.
Magtech 200 Grain FMJ 300 BLK Ammo
Similarly, 200gr Magtech FMJ can serve as the practice load for 200gr Winchester Super Suppressed open tip match load of the same weight. AmmoMan.com customers rate this ammo 5-stars. They point to flawless firing in Diamondback rifles with extremely quiet shooting.
Remington 220 Grain 300 BLK Ammo
The classic Remington 220gr open tip match offers similar accuracy with terminal performance typical of a long, non-expanding bullet. It likewise works very well for targets of hog size and density. Density and solid construction make it a credible performer on auto glass and bodies too.
Hornady 190 Grain SUB-X Hollow Points
On the lighter end, 190gr Hornady with SUB-X tipped hollow point still has excellent velocity retention for consistent expansion up to .50 caliber up close and around .45 caliber at further distance. This load is far better for deer. Its wide wound channel combines with sufficient 15 to 16 inches of penetration. Accuracy remains in the 1-1.5MOA range. SUB-X is an excellent home defense load. You’ll want to keep in mind that it will penetrate interior walls with ease: firing from a low angle when possible would put any misses into the ceiling obliquely, avoiding collateral damage downrange. Customers at AmmoMan.com call this 5-star ammo. They point to 2.5″ groups at 100 yards and praise the round’s quiet performance when suppressed.
Hornady’s Sub-X is one that we also included in our 300 BLK self-defense testing with gelatin, if you’re curious how it performed.
All of these cartridges have low flash, even unsuppressed, and a modest muzzle blast.
Where 300 Blackout Fits In
Since DeLisle carbine, 45 ACP was viewed as an obvious choice for suppressed long guns. It is naturally subsonic, heavy at 230 grains, easily available, mostly compatible with .30 caliber rifle breech faces. 9mm subsonics top out at 185 grains (Seismic JHP), but 147 grain is the heaviest bullet in common use. Once 300BLK became available, the disadvantages of 45 ACP relative to it began to show: the pistol cartridge doesn’t get up to the ideal 1050fps for lack of powder, its wide cross-section causes a rapid decline in velocity at distance, and wide bore doesn’t sound suppress as well as smaller calibers. The same limited powder volume that limits velocities also limits adaptation of 45 ACP to gas operated long guns.
Accuracy
Equally importantly, 300BLK is significantly more accurate than 45 ACP. 1-2 MOA 300 BLK runs rings around 4-6 MOA pistol cartridge. For best subsonic accuracy, barrel twist should be 1:7 rather than a slower compromise twist used by some makers who emphasize supersonic accuracy.
At 190 to 220 grains but higher initial velocity, 300BLK bullets have more energy at the muzzle than 45ACP, and the spread gets greater with distance. Much higher ballistic coefficient of the thin, long bullets comes into play. That extra retained energy gives bullet makers a fairly consistent expansion envelope out to 200 yards. Where 45ACP will be down to 700fps, 300BLK still moves along at 900fps, making consistent terminal performance possible. Bullet selection becomes important for achieving specific results on contact.
With the exit aperture around 44% of that in .45 caliber, .30 caliber guns suppress much better. With modern sound suppressors, 300BLK is ear safe and flash-less indoors. Designed for maximum performance in approximately 14″ barrel, 300BLK thrives in standard 16″ carbines, and loses less than could be expected in 12″ pistols. Shorter barrels make for better handling with suppressors attached. Integrally suppressed guns with manual actions, such as the upcoming Henry Supreme lever action model using AR15 magazines, are even quieter with only a slight reduction in the rate of fire.
To see our full in-stock selection of 300 Blackout ammo for sale, head here.
