.223 vs. 5.56 - Which Should You Choose? – Foundry Outdoors

.223 vs. 5.56 - Which Should You Choose?

If you are looking at the .223 or the 5.56 you may want to consider these points before making your purchase. 

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One of the more confusing things for folks new to shooting sports is the vocabulary that comes along with those sports. Whether you are confused about the differences between calibers and gauges, or shells and bullets, sometimes just learning the terms is half the job. If you are new to shooting sports, and have been browsing predator rifles, you might have stumbled across a conversation about .223 vs. 5.56 that left your head spinning. If you find yourself in this predicament, or just want to scope out more information on the subject, you have found the right place.

The Basics

.223 ammoFirst off, the terms .223 and 5.56 refer to the caliber of the rifle. The 5.56 is technically called a 5.56x45mm NATO and started off as a military cartridge in the 1950’s. By the 1960’s the cartridge was catching and Remington decided to release a very similar cartridge, the .223. Ever since people have been getting twisted up, and shook up, about the difference between the .223 and the 5.56.

Much of the confusion comes from the size of the cartridges. In fact, for the sake of argument’s sake these are essentially the exact same size. So, if they are the same cartridge, can’t they be shot interchangeably? Here is where most of the debate begins and where the astute gun student should pay close attention.


First off, debate of this topic can get fairly heated, but for safety’s sake it is wise to shoot only .223 rounds out of a .223 barrel and likewise with the 5.56. The major difference deals less with size and more with pressure. You see, although the cartridges are essentially the same size, the leade of the barrel is different. The leade is the portion of the barrel right in front of the chamber. This portion of the barrel does not have rifling in order to provide space for the seated cartridge. In general the 5.56 barrels have a longer leade, almost twice as long. This causes some differences in pressure exerted on the chamber. Some would say to dangerous levels.


5.56 AmmoHere is where the conversation gets pretty muddy. Both of these cartridges are tested by different organizations, as the .223 is a civilian round and the 5.56 is a military round. It may not make sense to the newbie, but you can’t compare the two through organizations that standardize information about firearms. Secondly, authority sources on the topic both argue the difference is “no big deal”, while others argue the pressure levels can be dangerous and mixing ammunition should be strictly avoided. Anyone interested in swapping the two cartridges should be encouraged to do their homework and decide for themselves what path they will choose.

The Differences

Hopefully you can understand the .223 and the 5.56 are very similar cartridges. So what’s the difference between the two? Well, to be honest, not much. That being said, you might keep these few differences in mind if you are considering buying rifles in either of these calibers.

First off, you might want to consider the differences when purchasing ammunition. Both of these can be bought relatively inexpensively. There does seem to be more options in .223, but good deals and a variety of loads can be found in 5.56 as well. Also, if you choose to interchange the two cartridges, you can more safely shoot a .223 cartridge in a 5.56 barrel. In that case, the 5.56 might be a good choice because you can have more choice in ammunition.

Again, any shooter’s choice to swap ammunition between these two cartridges does so at their own risk.

All told, a conversations discussing the .223 vs. the 5.56 is sure to get muddy. Some say you can swap their ammunition, some say you can’t. Either way you choose, both of these cartridges excel for target shooting, predator hunting, and even borderline deer rifles. Whatever you decide to do, make sure you know what ammunition you are loading into the rifle you are shooting. If you are ever unsure, make sure to inspect the barrel and see what is stamped on it, and on the casing of the cartridge. In the end if you shoot either caliber you’ll be sending a reliable and proven bullet downrange to your target.


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We offer cheap ammo and bulk ammo deals on the most popular ammo calibers. We have a variety of deals on Rifle Ammo, Handgun Ammo, Shotgun Ammo & Rimfire Ammo, as well as ammo for target practice, plinking, hunting, or shooting competitions. Our website lists special deals on 9mm Ammo, 10mm Ammo, 45-70 Ammo, 6.5 Creedmoor ammo, 300 Blackout Ammo, 10mm Ammo, 5.56 Ammo, Underwood Ammo, Buffalo Bore Ammo and more special deals on bulk ammo.

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Eric - Aug 28, 2020

The question I had hoped to find an answer to is whether there’s any reason to prefer 5.56 ammo over 223, or vice versa. My AR is 5.56 NATO and so it can shoot either… but which ammo is preferred? Seems like 5.56 comes in heavier grain loads and therefore is better for bigger game? (That’s my assumption, but is that correct?)

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