.338 ARC vs .300 Blackout: Choosing the Best AR Caliber for Your Build

The AR platform has become the ultimate modular rifle, and caliber choices are at the heart of its versatility. Two popular but very different options are .338 ARC (Advanced Rifle Cartridge) and .300 Blackout (300 BLK).

At first glance, these cartridges seem worlds apart: one is optimized for long-range precision hunting, while the other excels in short-barreled, suppressed setups. But which is better for your needs — and is there a case for owning both?

Let’s break down the differences in ballistics, effective range, recoil, hunting applications, and cost, so you can make the right call for your next build.

.338 ARC vs .300 Blackout: Choosing the Best AR Caliber for Your Build

Hornady introduced the .338 ARC to give AR-10 shooters a cartridge that bridges the gap between 6.5 Creedmoor and traditional .308 Winchester. It’s built for energy retention at distance and big-game hunting.

Key Ballistics

• Bullet Weights: 180–225 grains

• Muzzle Velocity: ~2,300–2,400 fps (200gr load)

• Energy @ 100 yds: ~2,500 ft-lbs

• Energy @ 400 yds: ~1,600 ft-lbs

• Effective Range: 800+ yards

Best suited for elk, moose, bear, and long-range target shooting.

.338 ARC vs .300 Blackout: Choosing the Best AR Caliber for Your Build

The .300 BLK was developed to give the AR-15 platform .30-caliber punch in short barrels, while being suppression-friendly. It shines in CQB, home defense, and hog hunting at moderate ranges.

Key Ballistics

• Bullet Weights: 110–220 grains

• Supersonic Loads: ~2,000–2,250 fps (125gr)

• Subsonic Loads: ~1,050 fps (220gr)

• Energy @ 100 yds: ~600–1,200 ft-lbs

• Effective Range: 100–300 yards (supersonic), ~100 yds (subsonic)

Best suited for short-barreled AR pistols, suppressed rifles, and medium game (deer, hogs) at close range.

.338 ARC vs .300 Blackout: Choosing the Best AR Caliber for Your Build

.338 ARC vs .300 Blackout: Choosing the Best AR Caliber for Your Build

.338 ARC vs .300 Blackout: Choosing the Best AR Caliber for Your Build

.338 ARC vs .300 Blackout: Choosing the Best AR Caliber for Your Build

.338 ARC for Hunting

• Ideal for big game (elk, bear, moose).

• Effective for hunters who need reach in open terrain.

• AR-10 platform gives sturdiness but adds weight.

.300 Blackout for Hunting

• Perfect for hog hunting at night with a suppressor.

• Great for deer within 200 yards.

• Compact setups ideal for brush country or blinds.

.338 ARC vs .300 Blackout: Choosing the Best AR Caliber for Your Build

• .338 ARC: Too much penetration, overkill for home defense. Built for outdoor, long-range engagements.

• .300 Blackout: Designed with CQB and suppression in mind. Subsonic 220gr with a suppressor is extremely quiet, controllable, and home-defense friendly.

.338 ARC vs .300 Blackout: Choosing the Best AR Caliber for Your Build

• .338 ARC: New, premium, limited supply. Reloaders benefit most.

• .300 Blackout: Widely available, cheaper, with military and civilian adoption driving production.

.338 ARC vs .300 Blackout: Choosing the Best AR Caliber for Your Build

• Go .338 ARC if:

  • You hunt big game or shoot long distance.

  • You want AR-10 power in a modern hunting cartridge.

  • You don’t mind paying more for ammo.

• Go .300 Blackout if:

  • You want a compact, suppressed, and versatile AR.

  • Your shooting is mostly sub-300 yards.

  • You’re looking for affordable ammo and lighter builds.

• Why Not Both?

  • Build a .338 ARC AR-10 for the hunt of a lifetime.

  • Keep a .300 BLK AR-15 pistol for home defense or hog hunts.

Check out Moriarti AR-10 .338 ARC Uppers and Moriarti AR-15 .300 Blackout Builds to start your dual-caliber collection.

.338 ARC vs .300 Blackout: Choosing the Best AR Caliber for Your Build

The .338 ARC vs 300 Blackout debate isn’t about which is “better” overall — it’s about application. If your needs lean toward long-range, high-energy precision, .338 ARC wins hands down. If you’re looking for a suppressed, compact AR for close-quarters or brush hunting, .300 Blackout is still king.

Smart shooters (and hunters) may find that the best solution is both, covering everything from hogs in the swamp to elk in the mountains — all within the AR platform.