February 12th, 2021

.223 Rem vs. 5.56x45mm NATO — What You Need to Know

.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 nearly 4.5 million 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 [with a standard short throat]. 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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February 12th, 2021

Gun Safety Extra Important Now with Many Schools Still Closed

NSSF gun storage safe safety locks NSSF

In school districts in many states, public schools remain closed due to concerns over COVID-19. That means kids are home, and in the Northern States with snow on the ground, those kids are stuck inside all day long. With more gun owners at home with their kids for extended periods, firearms safety is more important than ever. Given that fact, the NSSF reminds gun owners to keep their guns locked up so they cannot be accessed by children.

The National Shooting Sports Foundation (NSSF) and its partners urge gun owners to keep firearm safety a top priority and are making safety resources widely available as gun and ammunition sales increase, especially among first-time firearm purchasers.

NSSF gun storage safe safety locks NSSF

“During this stressful time and with children spending more time at home, the firearm industry reminds gun owners that protecting yourself and your family includes making sure your firearms are stored securely when not in use”, said Joe Bartozzi, NSSF President and CEO. “The last thing any firearm owner wants is to have their gun fall into the wrong hands, particularly those of a child or someone at risk of harming themselves.”

For anyone considering buying a gun, Project ChildSafe’s Road To Responsible Firearm OwnershipMany Paths to Firearm Safety video series helps gun owners determine the best safe storage device for their home/lifestyle. You also view the Safe Storage Options chart.

NSSF gun storage safe safety locks NSSF

NSSF encourages gun owners and non-gun owners to use the firearm safety resources available on its Project ChildSafe website. These include the McGruff Gun Safety videos for young children and this educational video explaining how to discuss gun safety with children:

“More parents are assuming the role of educators in their homes, so it’s a good to time have a talk with your kids about gun safety, even if you don’t own a gun”, Bartozzi said. “If you do own a firearm, be sure your family understands the safety rules regarding firearms in your home, and always store guns responsibly when not in use.”

For more information on firearm safety, visit ProjectChildSafe.org.

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February 12th, 2021

Bill Gravatt Named President of Creedmoor Sports Inc.

Bill Gravatt Capstone Precision Group Creedmoor Sports Sinclair Managing Director

Bill Gravatt has been named President of Creedmoor Sports. Bill has worked in the shooting and reloading industry for over 30 years. His experience includes: former owner and President of Sinclair Int’l and President of Capstone Precision Group (Berger, Lapua, Vihtavuori, and SK). Now that Bill has achieved important goals with Capstone (for whom he continues to serve as a board member), he is taking over as President of Creedmoor Sports, after serving as its Managing Director since the spring of 2020.

Greg Kantorovich, Creedmoor Sports CEO states: “We are excited to have Bill assume the role of President. His innovative leadership will continue to enhance our team’s mission of managed growth through strategic planning. Bill’s wealth of industry knowledge and ‘customer first’ mantra is second to none! This philosophy aligns perfectly with Creedmoor’s passion to serve our customers like family”.

As the President of Creedmoor Sports, Bill will direct operational and marketing activities for the company. He will also help with informational programs. Gravatt has previously served Creedmoor Sports as a Managing Director since the spring of 2020, and served as a consultant before that.

Bill Gravatt told us: “I am joining a great team at Creedmoor Sports. They are all driven in pursuit of exemplary customer service, they create well-made products, passionately participate in the shooting sport, and enjoy the daily satisfaction that comes from helping fellow shooters achieve their best.”

Reloading Procedures with Bill Gravatt

Bill Gravatt has decades of knowledge about reloading tools and procedures. Here are three helpful videos Bill Gravatt created for the Creedmoor Sports InfoZone:

How to Seat Bullets with Inline Press

How to Trim Cases with L.E. Wilson Trimmer

How to Clean Cartridge Cases

About Creedmoor Sports, Inc.
Since 1979, Creedmoor Sports has been supplying the precision rifle shooter with quality equipment. Specializing in competitive centerfire, smallbore, and air rifle accessories, as well as reloading components and tools, Creedmoor seeks to provide their customers with the right gear to help them achieve their personal shooting goals.

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