Here’s something that surprises a lot of AR-15 owners. Hornady sells far more 223 Remington loads than 5.56 NATO loads. If you search for Hornady 5.56 ammo, you’ll find a short list. In our catalog, the 5.56-stamped Hornady load is the Hornady Superformance 5.56 55 Grain CX Lead-Free. The good news: if your rifle is chambered in 5.56, you can also run Hornady’s full 223 lineup.
This guide explains the CX load, why the 223 versus 5.56 label matters, and which Hornady 223 loads make sense in a 5.56 rifle. Velocity and energy figures come from our catalog.
Hornady Superformance 5.56 55 Grain CX
This is a lead-free hunting load. Here’s what our listing shows:
- Bullet: Hornady CX, a solid copper hollow point.
- Velocity: 3,175 fps.
- Energy: 1,231 ft-lbs.
- G1 BC: 0.27.
- Test barrel: 24 inches.
- Intended use: hunting.
What “CX” means
CX stands for Copper alloy eXpanding. It’s a one-piece copper bullet. It’s built to open into petals and hold its weight. Because there’s no lead, it fits hunts where non-lead ammo is required. Rules vary by state, so check yours.
What “Superformance” means
Superformance is Hornady’s line that uses special powder blends to get more speed from a standard barrel. More speed helps a copper bullet open, since copper needs more impact velocity than lead.
223 vs 5.56: Why the Label Matters
The two rounds look the same from the outside. The difference is pressure and chamber shape.
- 5.56 NATO is loaded to higher pressure. 5.56 chambers have a longer throat to handle it.
- 223 Remington is loaded to SAAMI’s lower pressure spec for a tighter chamber.
- 223 Wylde is a hybrid chamber that handles both.
The safe rule is simple. A 5.56 or 223 Wylde rifle can fire both. A rifle marked only 223 Remington should fire 223 only. Check the stamp on your barrel and your rifle maker’s guidance. You can read the standards themselves at SAAMI.
Hornady 223 Loads That Work Well in a 5.56 Rifle
Since 223 ammo is safe in 5.56 chambers, many AR owners buy from Hornady’s bigger 223 list. Here are a few that fit common AR-15 jobs, next to the 5.56 CX.
| Load | Bullet | Grain | Velocity | Energy | Pack |
|---|---|---|---|---|---|
| Hornady Superformance 5.56 55 Grain CX Lead-Free | Solid Hollow Point (Hornady CX) | 55 | 3,175 fps | 1,231 ft-lbs | 20-round box |
| Hornady CX 223 50 Grain Superformance Lead-Free | Jacketed Hollow Point (Hornady CX monolithic copper) | 50 | 3,300 fps | 1,209 ft-lbs | 20-round box |
| Hornady Black 223 75 Grain Match Hollow Point | Jacketed Hollow Point (Hornady Match) | 75 | 2,790 fps | 1,296 ft-lbs | 20-round box |
| Hornady 223 73 Grain ELD Match | Polymer Tip (Hornady ELD Match) | 73 | 2,790 fps | 1,262 ft-lbs | 20-round box |
| Hornady Critical Defense 223 55 Grain FTX | Polymer Tip (Hornady FTX) | 55 | 3,240 fps | 1,282 ft-lbs | 20-round box |
| Hornady 223 55 Grain FMJ Boat Tail Training Ammo | Full Metal Jacket Boat Tail (FMJ-BT) | 55 | 3,240 fps | 1,282 ft-lbs | 50-round box |
For hunting
The Hornady Superformance 223 50 Grain CX is the 223 twin of the 5.56 load. It lists 3,300 fps and 1,209 ft-lbs. Pick whichever weight shoots better in your barrel.
For precision
The Hornady 223 73 Grain ELD Match lists 2,790 fps. In a 1:7 or 1:8 AR barrel, it’s a strong long-range pick. A 223 load may run slightly slower in a 5.56 chamber due to the longer throat. That’s normal.
For home defense
The Hornady Critical Defense 223 55 Grain FTX uses a soft polymer tip to help expansion through clothing. It lists 3,240 fps. Laws on defense ammo vary, so check your state and local rules.
For training
The Hornady 223 55 Grain FMJ Training is simple range ammo. It’s a good match to the CX’s 55-grain weight for practice.
Why Pick Hornady 5.56 CX Over Lead-Core Loads?
- Lead-free rules. Some hunts require non-lead bullets.
- Weight retention. Copper bullets usually hold together, which helps depth on hogs and deer.
- Full 5.56 pressure. More speed helps the copper bullet open.
The trade-off is that copper bullets need speed. If you run a short barrel, keep your shots close.
Twist Rate and Zero
A 55-grain copper bullet is longer than a 55-grain lead bullet. Most AR barrels with a 1:7, 1:8 or 1:9 twist handle it fine. Always zero with the load you plan to hunt with. Don’t assume your FMJ zero carries over.
Want a heavier copper option? Our Black Hills 5.56 ammo guide covers a 62-grain Barnes TSX load. For the full Hornady 223 range, see the Hornady 223 ammo guide.
Shop Hornady 5.56 Ammo
See the load in our Hornady 5.56 ammo category. You can also browse Hornady 223 ammo for more options that run in a 5.56 chamber, or compare every brand in 5.56 ammo. With the right chamber, Hornady 5.56 ammo and Hornady 223 both open up plenty of choices.
Frequently Asked Questions
Can 556 shoot 223 ammo?
Yes. A rifle chambered in 5.56 NATO can safely fire 223 Remington ammo. That’s why many AR owners buy Hornady 223 loads for their 5.56 rifles. The reverse isn’t advised: 5.56 in a 223-only chamber can raise pressure. Check your barrel stamp and your rifle maker’s manual first.
What is Hornady CX?
CX is Hornady’s one-piece copper alloy expanding bullet. It is lead-free and built to open into petals while holding its weight. It is a hunting bullet and needs enough impact speed to expand, so keep shots at sensible range.
Is Hornady 5.56 CX good for deer?
Where state law allows 5.56 for deer, a copper hunting bullet like the CX is a sensible choice at modest range. Some states set caliber minimums that rule out 5.56. Check your state’s hunting regulations before you go.
Does 223 ammo lose velocity in a 5.56 chamber?
It can, slightly. The 5.56 chamber has a longer throat, which can lower pressure and speed a little with 223 loads. Most shooters won’t notice it at normal distances. Confirm your zero with the exact load you plan to use.
