300 Blackout, or simply 300 BLK, has stormed the AR 15 market as the next best black rifle round. It carries quite a few benefits, an interesting ballistic coefficient, and it garners major Coolguy points by virtue of the military’s special operations community’s love for the suppressor-friendly round.
That begs the question: Why should you, oh loyal black rifle owner, future builder of a shiny, new AR 15, take the plunge and buy into a 300 Blackout upper? With the launch of our new site dedicated to this awesome round, we felt it only fitting that we break down the comparisons by starting with the AR’s gold standard: .223 and 5.56. Let’s begin!
300 BLK, .223, and 5.56 by The Numbers
The M4 platform has its detractors, but it’s still a very reliable, lightweight, effective rifle at any range when it shoots .223 or 5.56. Does 300 Blackout add any value? The former two cartridges offer impressive penetrating power for their size and, for being .22-caliber rounds, they pack quite a punch thanks to sheer velocity.
Comparing grain count, the average .300 Blackout round varies quite a lot, mostly because of the round’s core purpose: Suppression without changing gas systems. To compare, we must look at both supersonic and subsonic 300 Blackout loads.
.223 Remington and 5.56 NATO:
- Weight (average): 62 grains
- Velocity (average): 3,100 ft/s
- Energy (average): 1,300 lb.-ft.
300 AAC Blackout:
- Weight (average): Supersonic, 125 grain, Subsonic, 220 grains
- Velocity (average): Supersonic, 2,215 ft/s, Subsonic, 1,010 ft/s
- Energy (average): Supersonic, 1,350 lb.-ft., Subsonic, 500 lb.-ft.
We find supersonic 300 Blackout more than doubles the grain count of the comparatively anemic .223 and 5.56, while subsonic loads quadruple the load. Simply put, more grain weight = more punch, and 300 Blackout doesn’t disappoint in either load. But what about velocity, the other half of the two-piece pie?
To be sure, 300 Blackout’s speed table garners a dramatic range based on whether the load is intended for suppression. That said, unsuppressed 300 Blackout, with a 125-grain count, puts a wallop on any target with a bit more force than either .22 round.
Here’s where it gets interesting: A suppressed, 220-grain 300 Blackout load hits with just 500 lb.-ft. of force – almost a third less energy than a standard 5.56 or .223 load. But here’s the deal, suppressed 300 Blackout is intended for close range shooting. Even compared to a heavy-hitting .45 ACP with a 230-grain hardball bullet packing 327 lb.-ft., the 300 Blackout puts any big, slug-like pistol round or sub gun to shame.
300 Blackout does .22 Things Quite Well, and Much More
To summarize 300 Blackout, it really is a great match against 5.56 or .223 when supersonic and shooting 125-grain(ish) loads. You’re getting similar foot-pounds of energy in a round that’s just physically larger. The end result is much, much more trauma. Do those zippy little .22 rounds offer a noticeably higher ballistic coefficient? Maybe, but only past 4, maybe 500 yards.
On the flip side, can those .22 rounds reliably and accurately shoot subsonic and supersonic loads, without changing any of the rifle’s configuration? No. Can they pull off that magic in an SBR or AR pistol? A big nope. And that’s the beauty of .300 Blackout: It shares basically every component of your standard .223 or 5.56-chambered AR 15 (to include gas systems, bolt carrier groups, lowers, and magazines) but it seems to mythically function perfectly in any configuration, using any load. No other round’s capable of this sort of performance, and that’s why 300 Blackout lives up to the hype.