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March 12th, 2020

Fact vs. Fiction — .223 Rem vs. 5.56x45mm NATO Cartridges

.223 Rem Remington 5.56 SAAMI CIP 5.56x45 5.56x45mm NATO cartridge ammo pressure test luckygunner ultimatereloader Gavin Gear

Probably the most popular centerfire rifle round in the Western Hemisphere is the .223 Remington and its metric match, the 5.56x45mm. Though many folks use “.223 Rem” and “5.56×45″ interchangeably, there are some meaningful differences in specifications for the original .223 Rem and the 5.56x45mm cartridge, as adopted by the U.S. military and NATO armies. The default chamber throats are slightly different and the .223 Rem is rated at 55,000 PSI vs. 62,366 PSI for the 5.56x45mm.*

.223 Rem vs 5.56x45mm — Key Differences
There is a truly outstanding, very thorough article on the subject, published by LuckyGunner.com.** This involved extensive testing, with pressure monitors, of 5.56x45mm ammo in .223 Rem chambers. Those tests revealed the peak pressures. Here is one of the ammo test charts:

.223 Rem Remington 5.56 SAAMI CIP 5.56x45 5.56x45mm NATO cartridge ammo pressure test luckygunner ultimatereloader Gavin Gear

NOTE: “The observed chamber pressure for Federal XM855 5.56mm ammunition in a .223 Rem chamber exceeded .223 maximum pressures, but not by a massive amount. The ninth shot (the red line) was an underpowered cartridge which exhibited significantly lower velocity and pressure than the other rounds, so it was excluded from the average velocity and pressure numbers for this chamber.”

And if you’re curious, LuckyGunner also fired .223 Rem ammo in a 5.56x45mm NATO-chambered AR15 rifle. As you would expect, the peak pressures were significantly lower, but the .223 Rem ammo still cycled the semi-auto AR-platform rifle perfectly well:

.223 Rem Remington 5.56 SAAMI CIP 5.56x45 5.56x45mm NATO cartridge ammo pressure test luckygunner ultimatereloader Gavin Gear

READ FULL LuckyGunner .223 Rem vs. 5.56x45mm ARTICLE »

UltimateReloader.com Explains .223 Rem vs. 5.56x45mm
To explain the key differences between the .223 Rem and 5.56x45mm cartridges our friend Gavin Gear of UltimateReloader.com has created a very thorough 12-minute video. This covers the cartridge specifications and explains key considerations for hand-loaders. Gavin also addresses the oft-asked question “Can I shoot 5.56x45mm ammo in my .223 Rem chamber?” Gavin’s video is definitely worth watching. In fact, this is one of the most popular videos Gavin has ever created — it has been watched over 300,000 times on YouTube.

What Exactly Is the 5.56x45mm NATO Cartridge?
The 5.56×45mm NATO is a rimless bottle-necked intermediate cartridge family standardized by NATO with development work by FN Herstal. It consists of the SS109, SS110, and SS111 cartridges. Under STANAG 4172, it is a standard cartridge for NATO forces as well as many non-NATO countries.

Bullet diameter: 5.70 mm (0.224 in)
Maximum pressure (EPVAT): 430.00 MPa (62,366 psi)
Maximum pressure (SCATP 5.56): 380.00 MPa (55,114 psi)
Case length: 44.70 mm (1.760 in)
Rifling twist: 178 mm or 229 mm (1 in 7 in)
Parent case: .223 Remington (M193)

Ammo-Maker Federal Premium Compares .223 Rem and 5.56x45mm
Here is a video from ammo-maker Federal Premium explaining the difference between .223 Remington and 5.56x45mm NATO. Federal states that you may experience excessive pressures when firing a 5.56x45mm in a standard .223 Remington chamber:

One leading gunwriter has addressed the question of shooting 5.56x45mm ammo in .223 Rem chambers. He advocates caution (for more info, SEE pressure tests by LuckyGunner.com):

“I have received a slew of questions — many from first time AR-type rifle buyers — about the .223 Rem and the 5.56×45 mm NATO cartridges. Can I shoot 5.56×45 mm NATO in my .223 and vice-versa? Are these the same cartridge?

Externally, the two cartridge cases are identical. The main differences are that 5.56×45 mm NATO operates at a higher chamber pressure (about 60,000 PSI versus 55,000 PSI on the .223 Rem.) and the 5.56’s chamber is slightly larger than that of the .223 Rem. Also, the throat or leade is longer in the 5.56×45 mm chamber. What does this mean? You should not shoot 5.56×45 mm NATO out of a rifle that is chambered in .223 Rem. And be aware that some .223 Rem. ammunition will not reliably cycle through some AR-style .223 Rem. rifles, but it usually does. As a matter of fact, I have not encountered any difficulty with current .223 Rem. loads cycling through a 5.56 mm AR-style rifle.”
– Mark Keefe, Editor, American Rifleman


* According to the official NATO proofing guidelines, the 5.56×45mm NATO case can handle up to 430.0 MPa (62,366 psi) piezo service pressure. The U.S. SAAMI lists Maximum Average Pressure (MAP) for the .223 Remington cartridge as 55,000 psi (379.2 MPa) piezo pressure with deviation of up to 58,000 psi (399.9 MPa). The chamber for military 5.56×45mm NATO has a longer throat prior to the bullet contacting the rifling which results in lower pressures when firing 5.56×45mm NATO ammunition. If 5.56×45mm NATO is used in rifles chambered for .223 Remington the bullet will be engraving the rifling when chambered. which can increase pressures past SAAMI Max levels. NOTE: The C.I.P. standards for the C.I.P. civilian .223 Remington chamber are much closer to the military 5.56×45mm NATO chamber.

** The full-length LuckyGunner article is well worth reading. It even provides specifications for a number of .223 Rem reamer types, and compares the original .223 Rem, the 5.56x45mm NATO, and the modern .223 Wylde chamberings.

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September 24th, 2014

Eye Protection — LuckyGunner Labs Field Tests

If you’re one of those folks who doesn’t wear eye protection, you need to check out the LuckyGunner Labs Eye Protection Test. For those who DO wear safety glasses — don’t assume that everything is OK. Just because you purchased name-brand “safety glasses” doesn’t mean that you are getting truly effective protection. In fact, many forms of protective eyewear sold today are flimsy, or poorly made. Consequently, they won’t stop even low-energy, slow-velocity fragments.

CLICK HERE to Read Complete Eyewear Test Report by LuckyGunner Labs.

Lucky gunner eyewear testTwo years ago, LuckyGunner Labs conducted very extensive field tests of 28 types of eyewear, ranging in price from $7 to $220. Remarkably, some of the most expensive safety eyewear performed no better than $10 items. Many of the products failed shockingly — with the lenses coming right out of the frames when hit with pellets. LuckyGunner recorded these kind of failures even with ANSI Z87-“approved” eyewear. The reason is that the Z87 test is not tough enough: “The basic ANSI standard is referred to as Z87, and you’ll see this marked in a number of locations on most eye protection marketed to shooters. However, the Z87 impact standard involves a .25″ steel ball traveling at 150 fps — this is fine for protecting eyes from debris that might fall or be thrown, but is not extremely relevant to shooters, who are dealing with objects traveling at much higher velocities.”

Standard Impact speed Caliber/Size
ANSI Z87.1-2003
High Velocity
150 feet/second
45 meters/second
0.25″ diameter steel ball
(25 caliber)
Mil-PRF-31013
Vo ballistic test
640-660 feet/second
195 meters/second
0.15 inch diameter steel projectile (15 caliber)

The testers recommend you select eyewear that meets military specification (above and beyond ANSI Z87). The MIL-PRF-31013 Standard covers projectiles up to 650 feet per second. This is much more stringent. Additionally, you want to replace often-used protective eyewear every year or so. Long-term exposure to UV radiation can weaken polycarbonate and lessen its ability to withstand impacts.

SUMMARY — What to Look for in Protective Eyewear

THE GOOD — Eyewear Protects Against Direct Hit with .22 Short Bullet
APEL Revision Sawfly eyewear was shot with a .22 Short, pushing a 29 grain bullet at 710 fps. That’s not powerful by modern firearm standards, but this might be fairly representative of a ricochet bullet fragment. The Sawfly lens stopped this 29gr bullet with minimal damage to the cheek area.

Lucky gunner eyewear test
THE BAD — Remington Eyewear Lenses Separate. Right Lens Enters Eye Socket
The most gruesome example was the cheap Remington eyewear which shed both lenses back towards the eyes, one of which embedded itself into the eye socket. The real-world implications of this action are disturbing to say the least.

Lucky gunner eyewear test

THE UGLY — Prescription Glasses Failed Miserably
Many ranges don’t see any need for protective eyewear beyond prescription glasses. However, most prescription lenses offer little if any protection. If the prescription lenses are glass, this can create more problems. As shown below, these prescription glasses offered no ballistic protection, and, in fact, proved more dangerous to the eyes due to the flying glass shards.

Lucky gunner eyewear test

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Results Chart, Video Clips, and Photos copyright Luckygunner.com.

Summary and Conclusions:
For faster-moving projectiles such as ricochet fragments, you need high quality, tested eye protection. LuckyGunner recommends eyewear with a single (one-piece) lens for any activity where your face might be struck by small, fast-moving objects. Individual lenses detach from the frames once a certain level of force is reached, and they are driven back into the eye sockets, where considerable damage may be done. There are good examples of protective eyewear with two separate lenses, but a broad, one-piece lens distributes force much better.

Lucky gunner eyewear testA wide, comfortable, and preferably soft rubber nosepiece is critical. Along with good “arms”, this will serve to keep the eye protection in place and will also reduce the chances of the lens being driven down or back into the face with enough force to damage the orbital bones.

A frame that connects across the top of the lens, not individual arms which attach to the outside corners of the lens, is recommended. This will reduce the chances of the lens detaching from the frame under impact (it’s still possible, just less likely). Some types of eye protection actually use the frame to absorb impact and distribute force.

NOTE: Andrew, the author of the LuckyGunner Eyewear report, was a former Navy Corpsman. Accordingly, he is familiar with health and safety matters.

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August 23rd, 2010

LuckyGunner.com To Sell Guns as Well as Ammo and Supplies

Luckygunner.com warehouseLuckygunner.com is a rapidly-growing ammo and shooting supplies vendor with a unique business model. Luckygunner.com guarantees that all products displayed on its website are in stock. Using an advanced “real-time” inventory system, Luckygunner.com promises that “what you see is what we’ve got.” You can count on receiving your order within a few days, and not be caught in the uncertainty and delays of back-ordering.

Luckygunner.com warehouseLuckyGunner.com to Sell Firearms Soon
LuckyGunner.com recently obtained its Federal Firearms License (FFL) and plans to begin offering firearms for sale on its website in the coming weeks. Luckygunner is expanding to sell firearms (through local FFLs) in response to customer requests. The same In Stock-Shipping policy applies to all LuckyGunner.com inventory — including firearms. Luckygunner.com promises: “If you see it on our website, it will be in stock and ready to ship. Every time. No exceptions.” When you order before 3pm EST on a business day, your order will ship the very same day.

NOTE: Purchasers do not receive firearms directly. The buyer provides contact info for a licensed firearms dealer (FFL) in the buyer’s vicinity. The firearms are shipped to the FFL, and the buyer must then comply with all Federal, state, and local laws before taking possession of the gun(s).
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August 10th, 2010

Ammo Vendor Guarantees In-Stock Inventory and Fast Shipping

LuckyGunner.com AmmoYoung Entrepreneurs Launch LuckyGunner.com
What happens when two dedicated sport shooters, one of whom is an IT specialist, find they aren’t able to source the ammo and reloading supplies they need? Well, they start their own company! The acute ammo/component shortages of the past two years inspired the creation of LuckyGunner.com. LuckyGunner.com’s story is like most American success stories: a combination of hard work, entrepreneurial innovation, and some good fortune. The co-founders, both under age 30, successfully navigated the Obama-induced ammunition shortage, the Great Recession, and the normal challenges faced by all small-business owners to transform their idea into a shooting supplies website generating over $3,200,000 of revenue in its first twelve months.

LuckyGunner.com AmmoAmong ammunition and component vendors, LuckyGunner.com is somewhat unique — it “doesn’t do back-orders”. Through an advanced “real-time” inventory system, everything that displays on the LuckyGunner.com website is guaranteed to be in stock. LuckyGunner.com also ships orders fast — normally all orders placed before 3:00 pm EST will ship that same day or on the following business day.

Extensive In-Stock Ammo Inventory
Most of the loaded ammunition carried by LuckyGunner.com is for handguns, but the company is building up its selection of name-brand rifle ammo in popular calibers: .308 Win, .223 Rem, .243 Win, 30-06, 7.62×39 and more. And of course LuckyGunner.com maintains a huge supply of 22LR and 17HMR rimfire ammo in stock. Hand-loaders will be pleased to note that Luckygunner.com has plenty of primers in stock, of all flavors: CCI, Federal, Fiocchi, Remington, Winchester, Wolf.

Frustrations with Other Vendors Inspired Creation of LuckyGunner.com
Luckygunner’s founders had themselves experienced the frustration of waiting long periods for merchandise: “We were already customers of other online retailers and simply realized that all our normal sources were chronically out-of-stock.” This frustration was compounded by the common industry practice of accepting orders for out-of-stock product and then notifying frustrated customers only days later that the order could not be fulfilled for several weeks or months.

A New Business Model Based on Fast Shipping with No Back Orders
LuckyGunner.com was created to “deliver the goods” without long wait times. One of the company’s founders told us: “We are built exclusively on the twin ideas of fast-shipping and not doing back-orders — ever. The Obama-induced ammo rush prompted us to open our online doors because we just couldn’t find what we needed on a regular basis…and when we did find what we were looking for, we couldn’t be sure that the [other vendor] actually had it in stock or just hadn’t updated their website. Hence, the on-site live inventory counter next to each product listing. So far, our customers have responded really positively to this focus on fast shipping with no back-orders.”

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