4411 Mercury St, Suite 103 · Kearny Mesa, San Diego
Rifle ammo · the AR-15's cartridge
.223 Remington and 5.56 NATO, 55 to 77 grain, brass and steel case, over the counter in Kearny Mesa. They look identical and they are not quite the same cartridge — this page starts with the one difference that matters.
Start here
Look at your barrel before you look at the shelf. What it is stamped decides what it can safely eat.
The two cases share the same outside dimensions, which is why they fit the same magazines. The difference is in the chamber and the pressure: 5.56 NATO is loaded hotter and measured to a different standard, and a 5.56 chamber has a longer throat ahead of the case to accommodate it.
So the rule runs one way. .223 in a 5.56 chamber is fine. 5.56 in a .223-only chamber is the one to avoid. If the barrel is not stamped at all, find out from the maker before you shoot either.
The number on the box
Heavier bullets are longer bullets, and longer bullets need a faster rifling twist to stabilize. Your barrel's twist rate — stamped as 1:7, 1:8, 1:9 — tells you how heavy you can go.
Light · fast · the default
The classic load and the one almost every AR shoots well, from old 1:12 twist barrels to modern 1:7. Most bulk range ammunition is 55 grain full metal jacket, often boat-tail. If you do not know your twist rate, this is the safe choice.
Middle · the modern military weight
Heavier and a little better in wind, and a good match for 1:7 to 1:9 barrels. One caution: 62 grain does not mean steel core. The military M855 load is 62 grain with a steel penetrator and many ranges ban it — but plenty of 62 grain ammunition is ordinary lead-core. Read the box.
Heavy · long range · match
Match and precision loads, usually hollow point boat-tail. They hold velocity and resist wind far better at distance, and they need a fast twist — 1:8 or 1:7 — to stabilize. Out of a slow-twist barrel they can keyhole and tumble. Priced like what they are.
Twist rate, in one line
A 1:7 barrel spins the bullet once every seven inches of travel; a 1:9 once every nine. Faster twist (the smaller number) stabilizes longer, heavier bullets. Most light bullets are fine in fast barrels; heavy bullets are not fine in slow ones.
Counter mistakes
The three things that most often send a .223 buyer home with the wrong box.
Steel-cased .223 is usually cheaper, lacquered or polymer-coated, and not reloadable. Most ARs run it fine for practice. The catch is where you shoot: a number of ranges ban steel-cased or bi-metal ammunition on the line, and some check with a magnet. Brass case is accepted everywhere and can be reloaded.
Steel-core bullets (including green-tip M855) and steel-case ammunition are the two most common range restrictions on this caliber, and they are not the same thing — a brass case can carry a steel-core bullet. Our guide to ranges around San Diego lists what each one allows, but call the range if you are not sure; their rule is the one that counts.
California requires certified nonlead ammunition to take any wildlife with a firearm, statewide. That rules out ordinary lead-core .223 for coyotes and ground squirrels. Solid copper and other certified loads exist in .223; our lead-free hunting page explains what counts, and a phone call tells you what is on the shelf.
.223 and 5.56 are high-volume rifle calibers: one range trip can go through a few hundred rounds. Once your rifle runs a load reliably, buying 500 or 1,000 at a time is where the per-round savings are. The bulk ammo buying guide covers when a case pays off.
On the shelf in Kearny Mesa
Real boxes that have been across this counter and on the deals board. Pictured as printed, so you know what you are looking for on the shelf.
Recent .223 / 5.56 boxes on this counter came from PMC, Frontier, Scorpio, Federal — and that is a record of what we have sold, not a promise of what is on the shelf today. The shelf moves daily and this site is updated by hand, so call or text before you drive out and somebody will go and look.
Why there is no price on this page
Ammunition pricing moves with the wholesale market, and a figure printed next to a caliber is wrong within weeks. So we quote .223 / 5.56 on the phone, with a number that is true today. The one exception is the deals page, where a fixed price on a fixed quantity runs for a fixed week.
Before you drive out
A few minutes longer than buying anything else, and almost every problem we see at the counter could have been sorted out at home.
Ammunition and accessories only — no firearms, and no shooting range at this location. If you need somewhere to shoot what you buy, we keep a list of ranges around the county. Se habla español.
Common questions
Real questions from real customers, answered the way we answer them in person.
Only if the chamber is rated for it. A barrel stamped 5.56 NATO or .223 Wylde fires both. A barrel stamped .223 Remington only is built for the lower-pressure .223 load, and firing 5.56 in it can raise pressure beyond what the rifle was designed for. If the barrel is not stamped, ask the manufacturer before shooting either.
Yes. .223 Remington is the milder load, and a 5.56 or .223 Wylde chamber fires it safely. Some rifles are slightly less accurate with it because of the longer 5.56 throat, and a very few gas systems tuned for 5.56 may cycle a light .223 load less reliably — but it is safe.
55 grain is fine in almost any barrel, from 1:12 to 1:7, which is why it is the default. 62 grain wants 1:9 or faster. 69 to 77 grain match bullets want 1:8 or 1:7. A bullet too heavy for the twist rate can fail to stabilize and hit the paper sideways. The twist rate is usually stamped on the barrel.
No. Green-tip M855 is a specific 62 grain load with a steel penetrator in the core, and many indoor ranges ban it. Plenty of 62 grain .223 and 5.56 is ordinary lead-core full metal jacket. The box tells you which one it is; if it does not say, ask before you take it to a range with a steel-core rule.
At some ranges, not others. Steel-cased and bi-metal ammunition are common range restrictions, often checked with a magnet, and a steel-core bullet is a separate restriction. Brass-cased, lead-core ammunition is accepted everywhere. Check the rules for the range you are going to before you buy for it.
Call 858-987-0509 or text 310-499-3499 and we will quote today's price and check the shelf while you are on the line. The catalog carries no prices because ammunition moves with the wholesale market; when .223 or 5.56 is on the weekly deals board, the price is published on the deals page. This site is updated by hand, so treat nothing on it as today's inventory.
Stock & deal questions
Text is usually faster than a call. Send what the barrel is stamped, the twist rate if you know it, and what you are shooting — somebody will tell you what on the shelf fits.
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Keep reading
Closed Thanksgiving Day, Christmas Day and New Year's Day.
Calls only
310-499-3499Text only
Text anytime. Anytime — immediate during business hours, forwarded after hours.
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