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Rifle Ammo

5.56 NATO Ammo

In stock from $0.52 / round · 14 of 26 products available now

Two things decide what to buy: your barrel's twist rate, which sets how heavy a bullet it will stabilise, and what your chamber is actually marked.

In stock today

Cost per round
$0.52 to $1.39
7 Brands
AC Unity, Amend2, Federal, Hornady, Magpul, PMC, Winchester
Bullet weights
55, 62, 64, 68, 75 grain
Pack sizes
20, 30, 140, 200, 300, 500, 840, 1,000 rounds

Order before 4:00 PM ET on a business day and it ships the same day, then 1 to 5 business days in transit depending on how far it travels. You will see the arrival date before you pay.

Learn more about 5.56 NATO

At a glance

Also known as
5.56x45mm NATO, M193 and M855 in military loadings
Common bullet weights
55, 62 and 77 grain
Typical use
AR-15 range volume, carbine training and matches
Before you buy
Safe in 5.56 NATO and .223 Wylde chambers, not in a barrel marked .223 Remington only
Age to purchase
18+ (long-gun ammunition, attested at checkout)

5.56x45mm NATO is the cartridge the AR-15 was built around and the most-shot centerfire rifle round in America. It is light, cheap in quantity, flat enough inside three hundred yards that holdover is rarely the problem, and it recoils so little that new shooters can learn on it properly. Two things decide what you should buy: the twist rate of your barrel, which sets how heavy a bullet it can stabilise, and your chamber, which sets whether 5.56 pressure is safe in it at all. Both are worth getting right before you buy a thousand rounds.

What to know before buyingCommon questions

Before you buy

What to know about 5.56 NATO

What people buy it for

  • AR-15 range practice and carbine classes
  • 3-Gun and multigun competition
  • Patrol and home-defense rifles
  • Varmint and predator hunting
  • Service Rifle and across-the-course match shooting

.223 is safe in a 5.56 chamber. 5.56 is not safe in a .223-only chamber

This is the one rule that matters. 5.56 NATO is loaded to higher pressure than .223 Remington, and the 5.56 chamber has a longer throat ahead of the case mouth to accommodate it. Fire 5.56 in a chamber cut only for .223 and the bullet engages the rifling sooner, driving pressure higher still. Going the other way is always fine: .223 in a 5.56 chamber is safe, and often marginally more accurate. If the barrel is marked only ".223 Rem", treat it as .223-only. A .223 Wylde chamber is a hybrid cut that safely accepts both and is throated for accuracy.

Twist rate decides which bullets work

A 1:7 or 1:8 twist barrel stabilises the whole range, including heavy 69 to 77gr match bullets; this is what most current AR barrels use. 1:9 handles 55 to 62gr well and gets marginal above that. 1:12, found on older rifles and some varmint barrels, is for light bullets only and will not stabilise heavy ones. Buying 77gr match ammunition for a 1:12 barrel wastes the money; the groups will open up and nothing about the rifle is at fault.

M855 "green tip" has a steel penetrator

The 62gr M855 load carries a hardened steel tip under the jacket. That makes it magnetic, which means a great many indoor ranges prohibit it and it should not be fired at steel targets at close distance; it damages plates that handle ordinary ammunition fine. It is also not a match bullet. It is inexpensive bulk practice ammunition with a specific restriction attached; know that before the case arrives.

Bulk practice, then a smaller quantity of what matters

55gr M193-style ammunition is the cheapest way to shoot volume and is what most bulk cases contain. Anything you intend to rely on (a duty or defensive load, a hunting bullet, match ammunition for a precision rifle) should be bought and zeroed separately. Different bullet weights and makers land in different places at a hundred yards, so confirm the zero rather than assuming it carries over.

Questions

Common questions

Can I shoot .223 Remington in a 5.56 rifle?

Yes. .223 is loaded to lower pressure and is completely safe in a 5.56 chamber; some rifles shoot it slightly better because of the shorter bullet jump. The opposite is not safe. 5.56 NATO in a chamber cut only for .223 raises pressure beyond what that chamber was designed around, and it is not something to do on the basis that a friend has got away with it.

How do I know which chamber my rifle has?

Start with the barrel marking: most makers stamp "5.56 NATO", ".223 Rem" or ".223 Wylde" on the barrel or receiver. If it says .223 Rem only, treat it as .223-only. If there is no marking or the rifle's history is unknown, ask the manufacturer with the serial number rather than guessing; a gunsmith can also measure the throat directly.

What twist rate do I need for 77 grain match ammunition?

1:8 or 1:7. Heavy match bullets are long, and long bullets need a faster spin to stay stable. A 1:9 barrel is marginal with 75 to 77gr and may or may not shoot it well depending on the specific rifle and conditions; 1:12 will not stabilise it at all. The twist is usually marked on the barrel next to the chambering.

Is M855 green tip worth buying?

As cheap bulk practice ammunition, sometimes, but only if you can actually shoot it. Its steel penetrator makes it magnetic, so many indoor ranges refuse it and it should stay off steel targets at close range. It is not more accurate than plain 55gr and it is not a defensive load. If your range allows steel-core ammunition and the price per round is better, it is fine to plink with.

How much does 5.56 NATO cost per round?

5.56 NATO runs from $0.52 to $1.39 per round in stock right now. Every price on the page carries its cost per round beside it, so the comparison is one glance rather than arithmetic.

Is it cheaper to buy 5.56 NATO by the case?

Usually, yes. We stock 5.56 NATO from 20 rounds up to 1,000, and the cost per round beside each price is what shows whether a particular case actually beats the box. It is not automatic: a discounted box sometimes wins.

Which brands of 5.56 NATO do you stock?

AC Unity, Amend2, Federal, Hornady, Magpul, PMC and Winchester are in stock in 5.56 NATO today. Stock changes as the feed runs, so the list on the page is the current one.

What bullet weights does 5.56 NATO come in?

The 5.56 NATO in stock runs 55, 62, 64, 68, 75 grain. Weight changes how the round feels and where it prints more than most shooters expect, so it is worth matching what you already shoot.

Is 5.56 NATO in stock?

14 of the 26 5.56 NATO products we list are in stock right now. Out of stock items stay on the page rather than disappearing, so a link you saved still works and you can see what normally sits here.

Related calibers

Further reading