6mm ARC vs. 5.56 NATO: Is the 5.56 Obsolete?

The 6mm ARC is a flat-shooting (and newer) AR-15 cartridge with little recoil. The 5.56 NATO is the standard AR-15 cartridge, albeit not without significant flaws. In this 6mm ARC vs. 5.56 NATO comparison, we’ll learn if the 5.56 has finally been outdone or if you should keep your AR-15 chambered for it.

Overview of 5.56 and 6mm ARC Ammo

The 5.56×45 is beloved by many firearm enthusiasts (myself included), yet despised by others. It’s utilized by militaries worldwide because it is accurate, low-recoiling, and relatively inexpensive to fire. Civilians regularly use it for hunting (including deer, in some states), home defense, target shooting, and competitive shooting.

The relatively new 6mm Advanced Rifle Cartridge (ARC) is a low-recoil, flat-shooting round that’s ideal for long-range target practice. It promises to do what the 5.56 can’t, but it also has some downsides of its own (more on that later).

5.56 vs. 6mm ARC Pros and Cons

Neither of these rifle cartridges is perfect, as each has significant advantages over the other.

6mm ARC vs. 5.56 Ammo Specs

Ballistics Comparison: Velocity, Energy, and Bullet Drop

5.56x45mm Ballistics

Note: The following table was created using data provided by ammo manufacturers. Actual ballistics obtained with your firearm can vary considerably from advertised ballistics. Also, ballistics can vary from lot to lot with the same brand and type load.

For a more comprehensive breakdown of velocity, energy, and trajectory across dozens of popular 5.56 loads, check out our complete 5.56 ballistics guide.

6mm ARC Ballistics

Note: The following table was created using data provided by ammo manufacturers. Actual ballistics obtained with your firearm can vary considerably from advertised ballistics. Also, ballistics can vary from lot to lot with the same brand and type load.

For detailed ballistic data across the full range of 6mm ARC factory loads, visit our comprehensive 6mm ARC ballistics page.

Recoil and Shooting Experience

The 5.56 has minimal recoil: ~5 ft-lbs of free recoil energy, give or take, depending on which rifle and ammo you’re firing. It’s often surprising to new shooters how little an AR-15 chambered in 5.56 kicks, which is why I typically use it to introduce new shooters to the sport. As an experienced shooter, I enjoy taking my 5.56 rifles to the range because they’re easy on my wallet and my shoulder compared to most other rifle cartridges.

The 6mm ARC has more recoil: ~9 ft-lbs of free recoil energy. While that’s nearly double the 5.56’s recoil energy, it’s still very manageable (15 ft-lbs or less is manageable for most shooters). The main problem with the 6mm ARC is its shorter barrel life: you’ll only get ~5,000 rounds per barrel. Whereas you’ll get 10,000 to 30,000 rounds out of a 5.56 barrel.

Read the full comparison here: https://ammo.com/comparison/6mm-arc-vs-556

Source: https://freedombunker.com/2025/11/28/6mm-arc-vs-556/