Defensive Ammunition Selection: .223 Rem and 5.56 NATO Rifles

The rifle has some major advantages over the pistol or shotgun when used as a defensive firearm. The rifle is far more powerful than a pistol and offers a quicker reload than the shotgun. With standard magazines holding 20 or 30 rounds, the rifle offers a capacity advantage as well. As a shoulder-fired firearm, the rifle’s practical accuracy in rapid-fire trumps the pistol, and its relative lack of recoil allows for faster follow-up shots than the mighty 12-gauge shotgun. You can fire the rifle more quickly and more accurately than any other defensive choice available.

Stopping Power, Penetration and Liability

However, one big advantage of using a centerfire rifle cartridge for self-defense brings a serious concern along with it. The rifle’s ability to stop bad guys, penetrate barriers, and defeat soft body armor becomes a double-edged sword when considering the legal liability of over-penetration. Fortunately for civilians using the rifle as a defensive arm, a wide variety of ammunition choices are available, especially in the very common .223 Remington and 5.56 NATO calibers. At this point, I should mention these two calibers are NOT the same even though their external dimensions are very similar. Rifles built to withstand the significantly increased chamber pressure of 5.56 NATO can also shoot .223 Remington ammo without difficulty, however, the reverse is not always true. Know your firearm and use the proper ammunition for it.

Likely the worst choice for defensive ammo is the inexpensive Russian-made, steel-cased full-metal jacket rounds that we have all used for practice at one time or another. It’s affordable, and I have converted thousands of rounds of it into smoke and noise over the years. However, its full metal jacket bullet is a simple pointed nose design with a thick copper jacket around its lead core; it will not expand or fragment when it hits the muscle and bone of the bad guy. These bullets tend to travel straight through whatever they hit and keep going for quite a distance before eventually tumbling. Remember, if the bad guy dies from blood loss in a hospital hours later, it doesn’t matter—we are shooting to stop his aggression right now! This ammo offers minimal stopping power combined with maximum legal risk. We must plan being legally liable for everything struck by the bullets we fire. A bullet that drills a .223 caliber hole straight through the bad guy before blowing through the wall behind him is the worst combination possible.

The M193 Round

A slightly better option, while still being crippled by the full metal jacket bullet design, is the 5.56 NATO military specification M193 round. The 55-grain bullet is similar in outward appearance to other FMJ rounds, but features a thinner copper jacket around the lead core. When the bullet hits with sufficient velocity (greater than 2,600 feet per second or so), the extreme pressure of striking the target is sometimes too much for the thin jacketing to keep the bullet together. If the jacketing breaks at the cannelure, the groove around the bullet where the casing crimps to hold it, the bullet will fragment into several smaller chunks which spread out in all directions. They are unlikely to pass all the way through the bad guy’s body with enough force to do damage to anything else behind him. A 5.56 NATO round which fragments inside the chest cavity of a bad guy is very likely to stop him right there. Unfortunately, the fragmentation of the M193 round is not a consistent sure thing at all; even under strict testing conditions, only a certain percentage of rounds will do it. There is no evidence that the military wanted a fragmenting bullet design or was even aware that it could fragment when they adopted the M193 bullet way back in 1964. The fact that it does sometimes fragment is really an accident of bullet construction techniques rather than the feature for which it is now known.

The M855 Round

The other military specification round, the 62 grain M855 (USA) or SS109 (NATO) loading, can also fragment like the M193, but it doesn’t fragment as often or as violently.  The bullet design of the M855 is complicated, featuring full metal jacketing over the pointed lead bullet and a steel penetrator core at the bottom. It is slightly heavier than the M193 but offers less velocity. Designed in the 1970s specifically to penetrate one side of a Soviet steel helmet from a distance of 600 meters. seemed like a great idea at the time. In the real world, M855 has had some disappointing results. In the 1993 Battle of Mogadishu (Blackhawk Down), Delta Force soldiers reported frustration with shooting enemies multiple times only to see them get up and run away. The combination of their short-barreled (10.5-11.5 inch) CAR-15 type rifles and M855 ammunition did not produce enough velocity for the bullets to fragment; they traveled straight through the Somali fighters.

Today’s Bullet Technology

In recent years, bullet technology has grown tremendously. The old soft tip hunting ammo designs have been overtaken by hollow points offering expansion along with good weight retention.  These rounds form a mushroom shape limiting over penetration and devastating soft tissue, while holding the bullet together instead of fragmenting. Most recently, ammo makers have started capping their hollow points with a plastic ballistic tip. When the bullet strikes the target, the plastic tip drives backwards inside the hollow of the bullet, helping the bullet expand reliably and more consistently. Ballistic tip ammunition offers a good mix of penetration combined with reliable expansion and weight retention. Though sold for years as hunting ammunition, manufacturers have also begun to offer ballistic tip loadings specifically for law enforcement or personal defense. For most common defensive applications, this is the pinnacle of bullet technology at this time.

Inexpensive steel cased ammo intended for plinking and training is a poor choice for use when lives are on the line. Military specification loadings are better, but their performance is inconsistent compared to the latest generation of ballistic tip hollow points. When loading a rifle for defending your life, choose your ammunition carefully.

What is your favorite defensive rifle load? Tell us in the comment section.

This article originally appeared on September 13, 2011.

The Mission of Cheaper Than Dirt!'s blog, The Shooter's Log, is to provide information—not opinions—to our customers and the shooting community. We want you, our readers, to be able to make informed decisions. The information provided here does not represent the views of Cheaper Than Dirt!

Comments (27)

  1. The Alkasnokav (AK – created by the German philosopher Reshnuv Gaterbo) is easily the best 556 platform on the market for home defense. Using less gun powder to move the trigger, you won’t have to worry about over penetration. You can also use cardboard in front of the barrel to slow down the bullet to prevent any penetration. Best of luck!

  2. Home defense ammo choices: A. Polymer tip. B. Lead core hollowpoint
    C. soft nose. D. Jacketed soft nose. Is this order correct? ALso, would this same aplly to 7.62x39mm, too?

  3. First i’d like to state my preference, heavy weight rapidly expanding bullets like the polymer tipped ones I feel work best for home defense. As for the guy that said get the job done and worry later if the bullet goes through and injures someone else, glad he does not live next door to me. Also the guy that said something about bullets used for bears, where do you live that the locals are as tough as bears. Here is something to think about 3 rounds Hornady 180 grain .308 SST from my 18 inch S&W M&P 10 handloaded to minimum spec at 20 feet, conclusion fight over.

    1. I have to agree with “clyde”, the M855 is a Steel-Tipped Lead-Core Bullet while the M855A1, is a Steel-Jacketed Copper-Core Bullet. Copper, substituted the Lead-Core to reduce Lead Contamination to the Environment.

  4. The M193 round is an excellent choice, provided that you use it in the weapon that it was designed for. When used in an AR with a 1/12 barrel twist such as the M16A1, it will expand and fragment reliably. When used in a 1/7 or 1/9 twist barrel it will not work as well. I own several AR’s and the one that is my go to gun for home defense is an A1 clone. The M193 round fired from this rifle is superior to an M855 round fired from a A2 or M4. Plus the M193 is generally cheaper than M855 rounds.

    1. Hi Steve, I have a Stag model 3 that I am trying to get dialed in, Federal m193 and independence 5.56 shoot ok through it, but I’m looking for a nail pounder round. The barrel has a 1:9 twist and I have a Nikon P-223 BDC 600 on it for a scope. According to Nikon, the best round to use for accuracy is one with a polymer tip, but I am in the beginning stages of getting this AR dialed in, and would appreciate any advice, thanks.

    2. Daryl, Based upon my personal experience with 1/7 and 1/9 twist barrels the M193 is not the best choice for accuracy. The minimum weight that I would use in this barrel twist is a 62 grain bullet. I have achieved my best accuracy with bullet weights between 68-77 grain with a 1/9 twist barrel. I will probably start an argument with my opinion of polymer tip bullets, but I have never seen an advantage to them. The best advice I can give you is to buy a selection of ammo from different manufacturers with different bullet weights above 62 grains and see which one performs best in your particular rifle.

  5. Golly guys! Why not just get a Doberman Magnum, I think any consideration of ‘overbite’ will pale in comparison to overpenetration. Besides, overbite by your DM is more precisely what is wanted and while that alrm is sounding you’ll have time to grab your weapon of choice AND dial 911.

    Hope you can appreciate the tongue in cheek!

  6. James: Given those two choices, I too would agree with you; better to get the job done and roll the dice for that small chance of injuring a civilian than not get the job done and potentially get injured yourself. In the test I mentioned earlier, the safest round tested was .223 A-Max, which put a massive hole through the back of the first wall and failed to reach the second wall at all, but its terminal ballistics and overall penetration are abysmal. I wouldn’t feel underpowered with a JSP though… after all, they ARE rated for black bears. I think if it can take a bear, it can take a man. Maybe not in a single, mediocrely-placed shot, but that’s why ARs have 30-round magazines where shotguns have seven. And the first hit will certainly pause the fight and allow you to place a better one the second time.

    On the more materialistic side, reduced penetration through walls makes it less likely you’ll put a bullet across the house and through your multi-thousand-dollar flatscreen, or into the garage and through your car door or something.

    1. shooting a rifle inside a house?
      that sounds like it’s going to hit the big screen any way. throw the pet cat at him, that should give you time to call the morgue and get pistol. oh go for the head shot.

  7. Fresnel, thank you for running that search, and it is interesting to hear of an example of a round at least almost injuring a second person. I would not be surprised in the least if some examples can be found of innocent victims of such an incident; I do not deny that it is theoretically possible. My initial point is to look at the data, regards of what that data shows. Ideally, “facts” are not disputable. Only after that can each person then proceed to reach their own, but better informed, conclusion. My conclusion so far is that, given my objective of using ammunition that is most likely to incapacitate the badguy with the fewest shots (my definition of effectiveness) and the incredibly low probability of such a secondary injury occurrance, when choosing ammunition for my self-defense weapon I would rather use a round that is believed to be more effective but perforates the badguy than a round that is believed to be less effective but does not perforate the bad guy.

    Of course there are a zillion variables that affect the equation (at home, at work, out shopping, with others, alone, detached home, apartment, underground basement, concrete walls, thin dry wall, summer, winter, northern, southern, and on and on), and so really there can be a range of “right” answers.

  8. James: You’re probably right, and even though the odds are incredibly slim that it might happen, well… people win the lottery, right? And this is not a lottery I want to win.

    Also, I did a quick search for people shot because of over-penetration, and I found a British police marksman who shot another officer in the radio through a suspect by the name of Mark Duggan. The bullet stopped in the radio and didn’t injure the officer, but that’s close enough for me.

    Mickey: 12 gauge birdshot is better than nothing, but not by much. Anybody who knows their stuff would never recommend anything less than #1 buckshot, as anything else is horribly inadequate at any range past contact distance. Any shotshell that will reliably stop a man will go through several walls before stopping, there’s just no getting around that, so you might as well make it an effective manstopper and go for large buckshot or slugs.

  9. Fresnel, I reread what I wrote, and since there’s no “edit” function, I just want to add that I am not trying to be antagonistic toward you. I was being defensive, and in fact I will repeat that I agree with you and I think your post was right on target.

  10. Fresnel, first off my initial comment was not aimed at you, but at a line or two I saw in the article (which I think was excellent, by the way) which triggered my old “hot button” on the subject of “over-penetration.” Also, I certainly agree that misses are always worrisome–no matter what ammunition you are firing. I explicitly worded it the way I did because as far as I’m concerned, discussion of misses is a very different subject. My peeve is in particular aimed at discussion of self-defense ammunition where literally the concern raised is that the round could pass completely through the badguy and thereby become a danger to other people–and I have seen that argument raised *many* times. Yet I have never found any anecdotal evidence of this ever actually occurring, much less finding it to occur on anything close to resembling a statistically significant likelihood.

  11. Bobby,

    It has been proven over time that pistol rounds, with heavier mass and slower speeds tend to travel through several walls, thereby putting others at risk. The 5.56 NATO round is designed with a light front end and a heavy rear and and travels at greater speeds, causing it to tumble after striking an object and then fragmenting. They rarely over penetrate walls. I do agree with you though, that for the untrained person, a 12 ga with bird shot makes a better home defense weapon. If you routinely train with a weapon, then the rifle is a much better choice.

  12. Of course I am not some sort of “expert,” but I have followed reporting in the “Armed Citizen” column in The American Rifleman and other gun press for 30+ years, nearly all of which I have explicitly been watching for any incidents of “over-penetration” by any firearm injuring a second person. I can not recall *ever* reading a single instance of an armed citizen shooting a badguy only to have any of his rounds perforate the badguy and continue traveling until hitting a second person. I would very much like to read about *any* such examples. And then, if any can be found, do not think that proves much of anything until you consider how many (if any) there are compared to how many times a good guy shot a bad guy.

  13. It should definitely be noted that hollowpoint rounds of any caliber almost universally expand quite poorly in drywall, and thus tend to retain their shape and penetration power much like an FMJ would. Jacketed soft point ammo is far superior in this respect, and can deform enough to be incapable of penetration after passing through a single interior wall while still being a lethal defense round. I saw a test that showed that Winchester 68gr. JSP would bounce off the second wall it hit after passing clean through the first, and yet Winchester rates that ammunition as sufficient for cougar, deer, and bear. And that, Bobby, is why a rifle is a far superior home defense weapon. No other cartridge offers that superior mix of on-target effectiveness and off-target safety.

  14. I think it is grossly irresponsible to even suggest that a rifle of any kind is a defensive weapon. A rifle is an offensive weapon, always. Someone that doesn’t understand why should not be writing a firearms blog. A rifle is possibly the single worst choice for a firearm to protect the home for many reasons, and the primary one is that it is not a defensive weapon!

Your email address will not be published. Required fields are marked *

Your discussions, feedback and comments are welcome here as long as they are relevant and insightful. Please be respectful of others. We reserve the right to edit as appropriate, delete profane, harassing, abusive and spam comments or posts, and block repeat offenders. All comments are held for moderation and will appear after approval.