Gregory Kielma • October 21, 2023
223 Remington/5.56 x 45mm NATO Cartridge
223 Remington/5.56 x 45mm NATO Cartridge
Hey Gregory,
Today's workbench is written by guest contributor and AGI Certified Gunsmith and GCA Moderator Robert Dunn:
There isn’t a day of my life that goes by that I don’t work with, reload, think or write about the .223 Remington and 5.56 NATO cartridges. Those cartridges are what a couple of my favorite and most used rifles are chambered for.
When I worked in an ammunition factory, I would sometimes get paid in .223 ammunition. When I was growing up in the early 1970s I became familiar with the .223 Remington cartridge, as it was the new round being used by our Armed Forces.
Warfighters throughout the world had realized the advantage of automatic firepower, but finding the perfect firearm and cartridge design is a huge challenge. In the case of the .223 Remington, many sources helped bring this cartridge into use by both civilians and the military.
Eugene Stoner of ArmaLite (then a division of Fairchild Industries) had gained the attention of the Military with his 7.62 x 51mm chambered AR-10 rifle. Like many high powered rifles, the AR-10 was hard to control during automatic fire.
Consequently, Fairchild Industries and Stoner were asked to scale down the AR-10 to fire a smaller caliber cartridge. Stoner came up with a prototype AR-15 and after a demonstration for the army, he was asked to produce more rifles for testing in 1957.
Select engineers and other companies like Remington Arms, Winchester as well as ArmaLite were asked to take part in developing this project. Springfield Armory’s Earle Harvey lengthened the .222 Remington case to the required specifications and it became the .224 Springfield, which was commercially known as the .222 Remington Magnum.
Frank Snow (of Sierra Bullets) and Eugene Stoner calculated the ballistics data for the .222 Remington to find the best bullet for the project, which ended up being a 55 grain bullet. Meanwhile, the Technical Editor for Gun and Ammo magazine, Robert Hutton, worked up a propellant recipe that could attain a velocity of 3,300 fps. Ultimately, Remington came up with the .222 Special cartridge, which was later renamed the .223 Remington because there were so many .222 designations.
Just a few of the military requirements for the firearm and cartridges were that they needed to be able to penetrate one side of a US Steel helmet at 500 yards, had to be able to exceed supersonic speed at 500 yards, had to be .22 caliber and select fire. From years of research and development of the AR-10 and AR-15, ArmaLite was facing financial difficulties and sold the rights for the rifles to Colt in 1959.
The AR-15 and the T44E4 rifle that would later be known as the M14 were being testing at the same time. To make a long story short, it was found that the AR-15 had far less failures per 1,000 rounds fired and that riflemen had a higher hit probability when firing Stoner’s rifle.
After Air Force General Curtis Le May test fired the AR-15, he ordered a batch of AR-15s to replace some of the M2 carbines that the Air Force was using. As the trials and testing continued, it was found that during marksmanship testing that many more men were achieving Expert shooting status with the AR-15 than they were with the M14. With these findings and the failure rate of the AR-15 going down even further, General Le May placed an order for 80,000 rifles in 1961.
In 1962, Remington filed the specs for the .223 Remington cartridge with SAAMI (Sporting Arms and Ammunition Manufacturer’s Institute) and the cartridge was later marketed commercially as a chambering for the Remington 760 rifle in 1963.
At this point in time, the United States was embroiled in the conflicts arising in Southeast Asia. It was politically decided that contracts for rifle manufacturing could be bid on by the private sector and Colt was awarded the contract to provide AR-15 rifles to fill orders for the Vietnam War.
The AR-15 rifle and the .223 Remington cartridge were formally adopted in 1964 and designated the XM16E1 rifle, commonly referred to as the M16, and the 5.56 Ball M193 cartridge. It was decided that the South Vietnamese troops would be supplied with the M16 rifle. Eventually, the Air Force, the US Army, Special Forces, the Coast Guard, the US Navy, the Marines as well as the SEAL teams had orders in for M16 rifles and cartridges. In 1965, Colt received orders for 800,000 M16E1 rifle and over 28,000 M16 rifles.
The M16 and the 5.56 Ball ammo would go through some major growing pains as the rifles and cartridges were issued to troops in Vietnam. Besides not being trained on how to properly clean the gun, the rifle suffered from many types of jams and failures.
Broken extractors and extractor springs accounted for many ejection failures and through more research, it was found that the propellant being used in the cartridges was creating horrific fouling of the gas and bolt system. The ball powder that was being used also created a longer pressure spike, which caused the case to expand in the chamber but it would not contract enough to be extracted.
The extractor would simply tear through the case rim, leaving the stuck case in the chamber. By using a different propellant, chrome plating the barrels and replacing the buffer with a new design that slowed down the cyclic rate, along with some other design changes, the problems were gradually sorted out. Unfortunately many American lives were lost because of these errors.
The process of selecting a smaller cartridge for use by NATO forces began in 1960. The cartridge design was based on the .223 Remington cartridge and its development was placed in the hands of FN Herstal. The rimless bottlenecked cartridge was named the 5.56 x 54mm NATO cartridge.
In 1980, the 5.56 NATO cartridge became the standard NATO rifle cartridge (known as the SS109 for NATO and the M855 for the United States). The 5.56mm cartridges allowed the soldier to be able to carry more ammunition, which equated to more firepower and logistically many more rounds could be transported to hot spots around the world by weight than the larger 7.62 NATO cartridges. On a global scale this can equal a savings of millions of dollars.
The number of firearms that are chambered for the 5.56 NATO cartridge is too numerous to list here. Just think about all of the different squad automatic weapons, rifles, carbines and machine guns that each NATO country uses…that is a lot of different weapons!
The Frankford Arsenal, Remington and Winchester produced the first lots of .223 ammunition for the United States Armed Forces. During the trials and testing of the AR-15, 19 Million .223 cartridges were purchased. When a cartridge does well for the military, the Law Enforcement and civilian communities usually follows their lead. If you have ever read the 27 page document for the military specifications for the M855 cartridge (5.56 x 54mm), you can see that heavy scrutiny has already been applied to the 5.56mm round!
The .223 Remington cartridge has become one of the most used cartridges in the United States. It is a great varmint and predator cartridge and could be used for larger game if need be by loading a heavier bullet like a Hornady GMX or Barnes TSX 70-grain projectiles. These slower moving heavier bullets seem to do quite well in windy conditions. The above attributes make the 5.56mm round a flexible survival cartridge too.
You may have noticed or even been annoyed by the interchanging .223/5.56 terminology, here are of the important similarities and difference between the two cartridges. The case dimensions are exactly the same, though case thickness/propellant capacity can vary significantly between manufacturers which will have an effect on the resulting pressures.
The 5.56 x 45mm NATO or other military 5.56 ammo tends to be loaded hotter, so chamber pressures will be greater than the typical .223 Remington load. For this reason, .223 Remington rounds can be safely fired in a 5.56 chambered gun but 5.56mm ammo should not be fired in a .223 Rem chambered gun.
The reason for this really comes down to the differences in the chamber dimensions between .223 and 5.56 barrels. The throat/free bore and leade of a 5.56mm chamber is longer. The throat of the chamber is the unrifled section of the chamber just forward of the neck and gives the bullet a place to sit. Leade or lead is the section of the bore of a rifled barrel located just ahead of the throat of the chamber. It is a conical shaped transition from end of the throat to the fully rifled part of the barrel.
In an effort to gain more accuracy from the 5.56mm NATO cartridge, Bill Wylde created the .223 Wylde, which is a chamber design that utilizes the same external dimensions and lead angle of a 5.56 NATO cartridge and the freebore diameter of the .223 Remington cartridge. Another company that uses a proprietary chamber design to achieve better accuracy from the 5.56mm NATO cartridge is Noveske. A Noveske barrel is not cheap but they are known for their precision and high quality products.
SAAMI specs are followed by manufacturers in the U.S. loading .223 Remington ammo but those same manufacturers who also load 5.56 ammo do not follow SAAMI specs because the 5.56 rounds are loaded to military specifications and thus not held to SAAMI specs. In Europe, the international organization C.I.P. tests and sets the safety standards for firearms and ammunition. In countries that are regulated by the C.I.P., .223 Remington ammunition is proof tested at the same maximum service pressure as the 5.56 x 54mm NATO cartridges.
There have been a lot of challenges that had to be met throughout the history of the AR-15 and the 5.56 x 54mm cartridge. The twist rate of a barrel and the chamber dimensions greatly effect performance and accuracy. The shorter barreled M4 carbines and the requests for even shorter barrel lengths coming from the Special Forces communities have kept firearms and ammunition engineers busy. At this point in time, the AR-15 style rifles and the .223 Rem and 5.56 NATO cartridges offer a very reliable and accurate shooting platform.
The AR-15 rifle and .223/5.56 cartridge combination have gone through many changes together. They are still being used by our Military/Law Enforcement and civilian populations to good affect every day. This combo is a must for 3-gun competition. The .223 Remington cartridge is not overly expensive and there is always a wide variety of ammunition to choose from. There is a lot of surplus ammo to select from as well. Many other firearms are chambered in .223 Rem besides the AR-15 type guns.
The 5.56mm round is a good cartridge to reload for, as there is a huge variety of quality components to choose from as well. In 1964, the year I was born, these cartridges were the new warfighting cartridge and the US Armed Forces began using them. It’s easy for me to remember how many years these cartridges have been in use!
Become an American Gunsmith and continue to preserve our Firearm’s Heritage!
Robert Dunn,
Gunsmith & Community Moderator
American Gunsmithing Institute
Gunsmithing Club of America
5 accused antifa supporters plead guilty to terrorism offense in ICE facility shooting that wounded LEO By Jamie Stengle Associated Press DALLAS — Five people pleaded guilty Wednesday to terrorism-related charges after they were accused of supporting antifa in a July shooting that wounded a police officer outside a Texas immigration detention center. The charges brought by the Justice Department followed President Donald Trump signing an order that designated antifa as a domestic terrorist organization. Trump has blamed antifa for political violence. FBI Director Kash Patel has previously said the charges in Texas are the first time a material support to terrorism charge has targeted antifa. A police officer was injured in the July 4 shooting near Dallas outside the Prairieland Detention Center, where federal prosecutors say an antifa cell carried out an attack that included gunfire and fireworks aimed toward the facility. Nathan Baumann, Joy Gibson, Seth Sikes, Lynette Sharp and John Thomas each entered guilty pleas to one count of providing material support to terrorists in federal court in Fort Worth. They face up to 15 years in prison at sentencing. Sharp’s attorney, Erin Kelley, said entering the plea was “step one in a long process” before the sentence is actually determined. Lawyers for the other four defendants either did not immediately return messages Wednesday or comment. Cases against others also charged in the shooting remain ongoing. According to court documents, one member of the group outside the facility yelled “get to the rifles” and then opened fire as officers responded, striking an Alvarado Police Department officer in the neck area. He fell to the ground but was able to return a few shots. Prosecutors say more rounds were then fired at the wounded officer and an unarmed DHS correction officer. Court documents say Gibson, Baumann and Sikes were among those who were present the night of the attack and were arrested shortly after, while Sharp and Thomas were among those who helped the accused shooter avoid arrest until July 15. Others are scheduled for arraignment in the case next month, including Zachary Evetts, whose attorney, Patrick McLain, has said he’s seen no evidence to support the government’s view of the case. “Mr. Evetts has never been a member of anything like a ‘North Texas Antifa Cell,’ and from the evidence provided to us by the government so far, there is no evidence that such an organization ever existed,” McLain said Saturday. Days after that shooting, a man with an assault rifle fired dozens of rounds at federal agents and a U.S. Border Patrol facility in McAllen near the Mexico border, injuring a police officer. Authorities shot and killed the attacker.
Dalmin Muran DEPUTIES ARREST SACRAMENTO MAN AND SEIZE LARGE WEAPONS CACHE AFTER SUSPICIOUS ACTIVITY AT LOCAL SCHOOLS, BAILS OUT HOURS LATER Last week, the Sacramento County Sheriff’s Office Threat Management Unit, with assistance from the Sheriff’s Office Special Enforcement Detail (SED), Critical Incident Negotiations Team (CINT), and multiple other specialized tactical units, executed a search warrant on 29-year-old Dalmin Muran following an ongoing investigation into concerning and escalating behavior. The investigation was started after Muran was repeatedly observed engaging in suspicious activity at local schools in East Sacramento County, including Rosemont High School. In one instance, Muran drove his vehicle onto school grounds during nighttime hours and was seen wearing military-style clothing and night-vision optics. He complied when contacted by security, who told him he had to leave, despite insisting he should be allowed access since the schools are “public grounds.” He claimed to have prior military service during other contacts, although it was determined he never had . Muran also expressed interest in joining law enforcement. During the execution of the search warrant, Deputies recovered multiple law enforcement patches and tactical gear, including those from the Sacramento County Sheriff’s Office. They also discovered numerous firearms that had been modified from their original California-compliant configuration. One unserialized short-barreled rifle (sometimes referred to as a “ghost gun”) was also located hidden in the attic as the warrant was being served, along with hundreds of firearm parts and components used to build or alter weapons. Deputies also found multiple smoke grenades, flash bangs, and pepper spray deployable smoke grenades within the residence, further contributing to public safety concerns and the seriousness of the investigation. Muran was booked into custody at the Sacramento County Main Jail for multiple felony charges but was released on bond hours later. Detectives are concerned that there may be unreported incidents in which Muran represented himself as law enforcement and/or attempted to enforce laws. The Sheriff’s Office urges anyone who may have had suspicious contact with Muran, particularly instances in which he represented himself as law enforcement or attempted to enforce laws, to contact the Sacramento County Sheriff’s Office Threat Management Unit immediately through our non-emergency line at (916) 874-5115 for follow-up. The investigation remains ongoing.
Why do policemen carry their sidearms in open holsters? Is it easy for anyone to grab them? Gregg Kielma Unknown to most people with casual familiarity with firearms, virtually all holster (especially those used by law enforcement) have a locking system, even if it isn’t easily seen. In fact, I don’t know of any police departments that doesn’t require one on holsters. Now some are much more effective than others, but almost all of them require one. For civilians, especially if carrying concealed, this system just uses tension, but even most civilians use holsters with a locking system that needs to be disengaged before drawing a firearm. The best locking systems can, with practice, be disengaged while drawing, in one smooth action. The holster above is from Safariland and uses their GLS locking system . On the right-hand side is a small protrusion which is a lock release. If you are drawing correctly, as you grab the firearm your finger should automatically hit and release it. While it takes some practice to make it completely smooth, most concealed carriers and law enforcement should already be practicing their draws at least once a week. On the other hand, if you are unfamiliar with the system (which 99% of the general public is) you’ll have no clue how to disengage the lock and will only end up pulling the wearer’s pants up an inch or two. Even if you pulled hard enough to remove the holster completely from the wearer’s pants, you still wouldn’t be able to use the firearm as all proper holsters (which is all the holsters Safariland makes) completely cover the trigger (never buy a holster that doesn’t completely cover the trigger). Many manufacturers produce similar holsters that use their own unique proprietary systems, the one below just happens to be the one I’m most familiar with.
Gregg Kielma in his GUN SHOP What is an "idiot scratch" on a firearm? Kielma says, if you scratch your firearm, I can fix it for you. Give me a call and I’ll do my best to make it look new again. Let’s TAKE A LOOK at a friend and my thoughts. The 1911 is one of the most iconic handguns in the world. Dozens of manufacturers make them. You might find a cheap, used 1911 for as little as $200 if you shop. On the other hand, you could find a Cabot 1911 for around a million dollars. Regardless of how expensive it is, a 1911 is venerated within the gun community. Beloved. An “idiot scratch” is something you see most commonly on 1911s, especially those owned by inexperienced or careless gun owners. I don’t agree with calling anyone an idiot. I don’t think of myself as incompetent. I have a scratch. It just isn’t obvious. How does that happen? In my case, it was just the fact that I’ve disassembled and reassembled that thing in a lot of different scenarios, including in low light situations. I’ve probably disassembled and reassemble it literally hundreds of times for various reasons (including converting it to a .22lr pistol). Why does it happen? It has a spring in there pushing a peg forward. If not careful the spring will “pop” out and could scratch your firearm. The peg makes it slightly more difficult to get this slide stop in place. That’s what scratches your frame. People who are new, careless, or whatever sometimes sweep up to get that slide stop in place. Now remember that while you’re doing all that, you’re also holding the slide back just the right amount to get it all to line up so that the notch in the slide fits. Accidents happen. It isn't that big of a deal. I could probably buff mine out, it’s so light. I just don’t care. My 1911 is one of my least favorite guns to shoot. That’s why it sits in the safe 99% of the time when I go to the range. I’d rather be shooting my CZ 97B. I don’t care about such things and don’t judge people who have marks. They could be exceptional shooters and just… not care about cosmetics. Maybe it isn’t even their mark but rather one caused by the last owner. It doesn’t affect function. It’s just… guys giving each other the business, like “Clips” vs. “magazines.” Lol If you scratch your firearm, I can fix it for you. Give me a call and I’ll do my best to make it look new again.
Do gun owners realize there is a limit on how many guns they can own at a time? Thoughts from an avid reader of the blog. What’s your thoughts on this? It is true. But we don’t like to talk about this subject much. When I was a bachelor living in an apartment, a gun safe was impractical. And closets were…packed. So I had 4 cased rifles under my bed. When I was married and had kids, the gun safe was practical. I filled it. Now that we are empty nesters and less demands on my wallet…. I asked Senior Management if I maybe could get a bigger gun safe to put a few more guns in? Senior Management went all practical and rational (I hate when that happens), “Why do you need more guns? You hardly shoot the ones you have!” So, I bought a case of ammunition instead. Keep up the good work by asking anti-gun questions. It reminds us of the haters lurking out there. Do yourself a favor, stock up on guns and ammo. I will note that I am a typical redneck American gun nut. Working in technology, have couple degrees, bit over 800 books in my Kindle. Accuracy snob. Uninterested in anything rapid fire - hit with the first shot saves both time and ammo. Served in the reserves. Ready to protect the weak from predators - except we don’t even tolerate that here in the first place. Can’t remember how to skin a deer, it’s been years. Can build a campfire. live in the woods for a weekend on canteen of water and 3 trail bars, been even longer. Can remember how to train youngsters on safe handling and excellent marksmanship, recent as last week.
More Mixed Signals From The U.S. Justice Department On Second Amendment Support We’ve reported lately how the U.S. Department of Justice (DOJ) seems to have a somewhat schizophrenic attitude when it comes to supporting the Second Amendment. On one hand, the DOJ claims to be doing everything it can to restore Americans’ 2A rights. On the other hand, DOJ attorneys will defiantly argue in support of an obviously unconstitutional infringement. In late November, the Firearms Policy Coalition (FPC) and Second Amendment Foundation (SAF) lambasted the DOJ for trying to limit a critical Second Amendment court ruling. After a court ruled that the nationwide ban on concealed carry in post offices is unconstitutional, the DOJ filed a motion to limit the scope of the injunction to only the named individual plaintiffs and to members of SAF and its partner organizations, but only to those who were members when the complaint was originally filed and who have been identified and verified. In other words, the government wants to keep the ban intact for the rest of America’s lawful gun owners. “The critical thing to remember here is that the government is fighting tooth and nail to continue enforcing an unconstitutional law against as many people as possible,” SAF Executive Director Adam Kraut said. “The DOJ’s position that it would be ‘impossible’ for it to know who was protected by the injunction without a membership list is just plain silly. If officials want to know if someone found to be carrying at a post office is a SAF member, they can simply ask.” Less than a week later, Reuters published information about a leaked DOJ plan to expand gun-rights protections with a new office in its civil rights division dedicated to enforcing the U.S. constitutional right to bear arms. The office, called the Second Amendment Rights Section, is expected to open on December 4 and will be dedicated to investigating local laws or policies that limit gun rights, something the Trump Administration has promised since its first week in office.
Michigan Governor Whitmer Surprise: Whitmer’s Anti-Gun Task Force Says Stricter Gun Laws Are The Answer To Violence Mark Chesnut “Garbage in, garbage out” is an old computer science axiom that describes how flawed, biased or poor-quality input will produce equally flawed, biased or poor-quality output. Of course, the principle doesn’t only apply to computer science. The entire gun control world often operates on this same premise. So, consider how unsurprising it truly is that a task force that Democrat Michigan Gov. Gretchen Whitmer created to make policy recommendations to curb violence is urging state lawmakers to ban the possession of so-called “assault weapons” and “large-capacity” magazines. According to a report at michiganadvance.com, Dr. Natasha Bagdasarian, the state’s chief medical executive and the task force’s chair, said the group used a “public health” approach to addressing “gun violence” in the state. “There are a lot of issues here that have not historically been thought of as public health issues, and only when we’ve taken this really comprehensive public health approach have we been able to implement real change,” Bagdasarian told the newspaper. “Gun violence is one of those issues.” It’s easy to immediately see how much garbage went into this project, resulting in the garbage that came out. First, Whitmer tasked the group with finding an answer to the “gun violence” problem. That is, indeed, garbage.
Florida: Pro-Gun Bill Repealing Adult Age Discrimination Advances to House Vote Yesterday, the House Judiciary Committee voted 13-7 to favorably report pro-gun House Bill 133, which restores the ability for young adults to lawfully purchase firearms. The bill now heads to the full House, where it is eligible for a vote when the 2026 regular session begins in January. House Bill 133, sponsored by Rep. Tyler Sirois, restores the ability for young adults to acquire firearms by lowering the minimum age requirement to purchase from 21 to 18. Since 2018, Florida has completely banned 18-to-20-year-olds from purchasing a firearm of any kind, for any purpose. A young adult in violation faces stiff penalties, including up to five years of imprisonment, a fine of up to $5,000, or both. On May 16th, the NRA filed a petition for a writ of certiorari in NRA v. Glass, requesting that the U.S. Supreme Court hear its challenge to Florida’s law prohibiting adults under 21 from purchasing firearms.
Brady X Poster Gets Undies In A Bundle Over ‘Less-Than-Lethal’ Weapons Proposal Mark Chesnut When an organization goes somewhat berserk on social media, passionately stringing post after post together ostensibly to make some kind of point, you’d normally figure that topic is probably a top priority of that group. That’s why gun-ban group Brady’s recent freak out over less-than-lethal weapons is somewhat bewildering. Brady: NONSENSE Brady, formerly called Handgun Control Inc. before leaders learned that most Americans were against “controlling” handguns, has never seen a gun control scheme that it didn’t embrace. But until the recent flurry of social media activity, so-called less-than-lethal weapons didn’t seem to be on the group’s radar much. That changed big time on November 19, when whoever was handling the organization’s X (formerly Twitter) account. “While the world focused on the Epstein files, Congress took up a dangerous bill that sponsors say is to help law enforcement get greater access to ‘less-than-lethal’ weapons,” Brady posted in a typical manner critical of anything seemingly in the pro-self-defense category. “In reality, it deregulates dangerous weapons to help a billion-dollar weapons industry make more money.” That’s all well and good, but the author seemed not to be able to let the matter go, soon posting more on the topic just a few minutes later. “This bill isn’t from a well-intentioned lawmaker or a group working to prevent deadly police violence,” Brady posted. “It’s backed by the manufacturers of so-called ‘less-than-lethal’ weapons, like tasers, who have started making products that are appropriately classified as guns under the law.” Still apparently not having said enough, the Brady writer entered rant mode with yet a third post a short time later. “In their effort to skirt the regulation of their products, this bill would narrow the definition of firearm and open a new market for untraceable ghost guns, which have already led to thousands of deaths in the last decade,” Brady posted.
Extremely Troublesome Department Of Justice Brief Draws Stark Warning From GOA Mark Chesnut A bold brief, recently filed by the U.S. Department of Justice (DOJ) in a case challenging the National Firearms Act (NFA), has one gun-rights organization sounding an alarm. According to Gun Owners of America (GOA), on November 20, the DOJ, in the case Silencer Shop Foundation v. ATF, filed an “outrageous brief that embraces an alarmingly expansive theory of federal authority.” That assertion runs directly afoul of President Donald Trump’s promise to protect the Second Amendment for all Americans. In responding to GOA and GOF’s “One Big Beautiful Lawsuit,” the DOJ treats Congress’ removal of the historic $200 tax as a pretext to rewrite the limits of congressional power, advancing an argument that would open the door to federal regulation far beyond anything the Framers intended. “GOA and GOF condemn Attorney General Pam Bondi and President Trump’s Department of Justice (DOJ) for doubling down on enforcement of an archaic and unconstitutional law while simultaneously offering legal theories that would expand federal power to historic levels,” GOA said in a news release revealing the DOJ’s actions. “This is especially striking from an administration that had promised to respect the Second Amendment and review burdensome agency rules.” As GOA further explained, the implications of the DOJ’s stance are immediate and ominous.
