.223 Rem/5.56 Ammo
The .223 Remington and 5.56x45mm NATO are the most widely used rifle cartridges in America, chambered in the AR-15 and its variants as well as bolt-action and semi-automatic sporting rifles across every major manufacturer. Both fire the same .224-inch diameter bullet and share similar external dimensions, though they differ in chamber pressure specifications. We carry a full selection of FMJ practice loads, defensive hollow points, and match-grade ammunition from all major manufacturers for both .223 and 5.56 platforms.
Read our full .223 / 5.56 Ammunition Buying Guide ↓
.223 vs. 5.56 — What’s the Difference
The key difference is chamber pressure: 5.56 NATO runs at higher pressure than SAAMI .223 specifications. A rifle with a 5.56 NATO or Wylde chamber can safely fire both .223 and 5.56 ammunition. A rifle with a .223 chamber should only fire .223-spec loads; shooting 5.56 in a .223 chamber can produce higher-than-designed pressure. Most AR-15s sold today use a 5.56 or Wylde chamber that accepts both safely. Check your barrel’s chamber marking before mixing ammunition types.
FMJ and Steel-Case Practice Loads
For high-volume range practice, FMJ loads from Federal American Eagle, Winchester USA, Hornady Steel Match, and PMC Bronze offer reliable performance at reasonable prices. Steel-case .223/5.56 from Tula and Wolf is the most affordable option and fine for practice, though it produces more carbon buildup and more extractor wear than brass over many thousands of rounds. For semi-automatic use, either works well; some precision bolt guns prefer brass case for more consistent neck tension and accuracy.
Defensive and Home Defense Loads
For home defense in AR-15 platforms, purpose-designed expanding loads like Federal Fusion MSR, Hornady TAP, and Speer Gold Dot are preferred over FMJ, which over-penetrates through drywall. The 55-grain and 62-grain loads are most common in AR-15 defensive configurations. At typical indoor distances, quality expanding .223 loads provide reliable terminal performance while reducing over-penetration risk compared to heavier pistol calibers. Verify function with your chosen defensive load in your specific rifle before relying on it.
Match Loads
For precision AR-15 and bolt-action work, Hornady ELD-M in 52 and 73 grain, Black Hills 77gr Sierra MatchKing, and Federal Gold Medal in 69gr SMK are among the most accurate factory loads available. Heavier bullets (69–77gr) perform better at longer ranges due to higher BC; lighter bullets (55–62gr) are adequate inside 300 yards. Heavier bullets require a faster twist rate to stabilize—most AR-15s with 1:8 or 1:7 twist handle 77-grain bullets; 1:12 twist barrels are limited to 55 grains and lighter.
Buying in Bulk
.223/5.56 is one of the most cost-effective centerfire calibers to shoot in volume. Cases of 1,000 rounds are the standard bulk purchase for regular AR-15 shooters. Per-round cost drops significantly at case quantities versus box pricing. Steel-case 1,000-round cases represent the lowest per-round cost available; brass-case Federal and Winchester offer better consistency for reloaders and precision use. Buying ahead of demand spikes—which historically occur during political events—is a sound approach for regular AR-15 shooters.
Related Pages
Browse our rifles page for AR-15 and .223/5.56 bolt-action platforms, or see our AR-15 pistols page for short-barreled AR options. Visit our rifle ammo overview to compare .223/5.56 against other calibers.