300 Blackout vs 556 – Which Caliber is better? By: AmSJ Staff


We all love the AR platform because its so reliable and as long as you keep it maintain, it can last a life time. The only drawback from this platform is the 5.56 cartridge. Some folks want a little more punch.


There have been some cartridges that have come down the pike as an alternative, but the only one that stands out is the .300 AAC Blackout.The .300 AAC Blackout was designed to give the AR platform extra umph in terms of power and penetration on intermediate ranges with reduce recoil while holding the 30 round mag.

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Its original intent was to provide outstanding terminal performance and accuracy going through suppressed with subsonic or standard ammunition. So here are the numbers.Strengths & WeaknessesBoth calibers are used for the same general purpose.Both cartridges are perfect for target shooting, hunting, home defense, and plinking.Somethings to consider from each strengths & weaknesses.


5.56-The 5.56 is half the cost of 300 BLK and is available in more high-end loading suitable for precision rifle fire.-The 5.56 also shoots flatter, has less recoil, and the ammunition weighs about 40% less.-The 5.56 is also safer for use inside a building for home-defense because the rounds are designed to break apart upon impact..300 Blk-The .300 Blk has a wider range of projectile choices– Due to the .30 caliber bore, burns its full potential in a 9-inch barrel, and is a much better choice for hunting.-Has the ability to cycle both super and subsonic ammunition without modification.– Its strengths shines with short barreled rifles and silencers and when barrier penetration might be needed.– Whether for hog hunting from 0-200 yards or conducting CQB work, this baby is godsend.

The table above you can see the compared ballistics of both the 300 BLK and the 5.56 NATO.– Shows the barrels that the cartridges were designed approximately 20-inches for the 5.56, 9-inches for the .300 BLK, and the most popular civilian barrel length of 16-inches.–Exterior ballistics are the qualities associated with how a projectile flies through the air.**The wind drift, bullet drop, and zero range all fall into the category of exterior ballistics.**

You can tell that the 5.56 is significantly flatter than the 300 BLK in flight.This is due to a faster velocity.-The .300 BLK uses bullets with a higher ballistic coefficient but isn’t moving fast enough to take advantage of its sleeker projectiles.This is why the 5.56 shoots flatter, with less wind drift although having almost half as much energy.Terminal BallisticsTerminal ballistics of a round are the qualities it has when it hits the target.The sectional density, the relationship of its mass and its weight, its ability to penetrate rather than fragment, and the wound channel it creates due to its bore size are all the study of terminal ballistics. (tissue damage)It’s important to note that while energy numbers can give you an idea of power around is, it’s only a single data point.The stouter bullets, with more mass of a larger caliber seems to be the more effective round.To the untrained observer the 300 BLK seems to have the edge in terminal ballistics.So which is better?Target shooting, training, or plinking is just plain fun.-It can get expensive when shooting so many rounds, so this round goes to the 5.56.-The 300 BLK’s lethality and stopping powers isn’t needed when all you’re doing is punching targets that don’t fight back.If you’re pressed with the $ issue, stick with the 5.56.

Home DefenseFor home defense, you should be thinking heavy hitters, walk softly and carry a stick chambered in 300 BLK.-Having a suppressor with subsonic ammo in a home defense situation is ideal for your hearing.-The .300 BLK is still great when you either can’t or care not to have NFA firearms.-If you find yourself in a state like California defending against zombies, with a tight magazine ban and zero NFA goodies, get the bigger bullet.

HuntingWith modern bullet designs the gaps between the killing power of calibers is shrinking.-If you’re into small game, go with the 5.56. The wide range of factory loading for predator hunting edges out the 300 BLK.-If you plan on hunting medium or large game such as deer, hogs, or smaller bears, the 300 BLK is far superior.-The extra mass gives more reliable penetration than the 5.56.Here’s a video that demonstrates the comparison visually from Youtuber Langley Firearms Academy.https://www.youtube.com/watch?v=QIL3Ycaz9VE

In the EndThe .300 BLK will never replace the 5.56 for the most ubiquitous AR-15 cartridge but it does have some key areas where it really shines.Let us know below when you can think of a time where you wished your AR-15 had some “umph” to it?

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