NO, not both ways. You can shoot .223s in a 5.56 chamber but not the other way around. The 5.56 has higher pressures and what’s called a longer “leade”. The end of the case is a little but longer that can get crammed in a .223 chamber.
You can go to SAAMI and search for drawings of both and the diagrams will show you the difference. Don’t let anyone tell you differently.
No! .223 can be used in 5.56 BUT NOT THE OTHER WAY AROUND.
Well the .223 actually gets fired...
Are you sure you want to use Nato ammo? Being of Nato, it might misfire.
.223 in 5.56 marked barrel is ok, visa versa not so good.
Google search, there is a ton of stuff online on the topic
While the cartridges are identical other than powder load, bullet weight, chamber pressure and the chamber leade (throating in the USA), i.e. distance from the projectile while seated in the case to the rifling is typically shorter in .223 Remington commercial chambers. Because of this, a cartridge loaded to generate 5.56×45mm NATO pressures in a 5.56×45mm NATO chamber may develop pressures that exceed SAAMI limits for .223 Remington when fired from a short-leade .223 Remington chamber.
The chamber pressure is measured differently (CUP vs. PSI) but the 5.56 is a bit hotter than the .223 Rem. You can always use .223 in a barrel chambered for 5.56 but shouldn’t use 5.56 in a .223 barrel. The .223 Wilde chamber is a compromise and can fire both.
You can use .223 in a 5.56, but you cannot use 5.56 in a .223.
There is quite a lot of technical reasons...chamber pressures, headspace, etc, but suffice to say, do not intermix...to do so invites consequences which most likely would be disappointing, not the least of which would be damage to the weapon.
Google it...there are many, many good articles on the web that can do a much better job of explaining it.
Just use 223. Unless you are wanting to punch through body armor, why shoot NATO pressure ammo. You are needlessly sacrificing accuracy and beating your gun up on the process.
If you are going to war, the answer is different.
http://ammunitionstore.com/pages/news/the-difference-between-223-and-556-ammunition-223-vs-556/This answer is from:
The Difference Between 223 and 5.56 Ammunition – 223 vs 5.56
Understanding the difference between 223 Remington and 5.56x45 NATO ammo is something that can confuse even the most experienced rifle owners. This can largely be attributed to the prevalence of incorrect 5.56 vs 223 information that has been published on the web in the last two decades.
The problem is that a lot of this information is presented as factual when it couldn’t be further from the truth. Unfortunately this information is often regurgitated by others as fact which leads to even more misinformation. So what’s the real difference between 223 and 556 ammo, and which can be used in your rifle? Continue reading to find out!
Here are a few facts when it comes to 223 Rem. vs 5.56 ammo.
•Physical dimensions of 223 Remington and 556 ammo are practically identical.
•Typically, 5.56 chambers will be less pressurized than their 223 chamber counterparts. 556 ammunition is often loaded to higher pressure than its 223 counterpart.
•5.56mm rifle chambers do not have the same dimensions as .223 chambers - it is this difference in critical areas of the barrel that prevent these ammunition types from being completely interchangeable.
What’s the difference between 223 Remington and 5.56x45 ammo?
Knowing those facts, what is the real difference between 223 and 5.56 ammo? To understand the difference between them, it is obviously important to understand what each ammo type actually is. After all, you can’t compare two things if you don’t understand both individually.
What is 223 Rem. ammo?
223 Ammo is essentially slang for the 223 Remington cartridge, and as we mentioned, it does share nearly identical external dimensions with the 5.56 cartridges. Let’s take a look at some facts about 223 cartridges:
•They are loaded with .224 inch diameter bullet.
•Weights range between 35 to 80 grains, with the most common varieties being 55 and 62 grain which weigh in at 3.6 and 4.02 grams.
What is 5.56 NATO Ammo?
5.56 ammo is essentially 5.56mm NATO. NATO is responsible for creating standards for military issued calibers.
A lot of ammunition manufacturers will imply that these calibers can be used interchangeably. While that is sometimes true, it requires expert knowledge and if you do not know what you are doing can be extremely dangerous if not fatal.
Ultimately, the only way to ensure you are using the correct ammo is to check to see what’s stamped on the barrel of your gun and to consult your owner’s manual. Although these calibers are often used interchangeably, if you do not know what you are doing you
Summary:
Ultimately, the only way to ensure you are using the correct ammo is to check to see what’s stamped on the barrel of your gun and to consult your owner’s manual. Although these calibers are often used interchangeably, make sure that you only use ammo that has been approved by the manufacturer of your firearm.
Stick with .223.
You rifle will last longer and the ball is cheaper.
I know the difference between them and I have shot both in various rifles over the last forty years. I’ve found both are safe even though the handwringers say they are not.
My current rifle is listed as 5.56 on the box and .223 on the rifle.
I no longer worry about it in either rifle.
The difference is the thickness of the case and the pressure. And I wouldn’t shoot 5.56 in a .223 weapon even if some of them say you can. But you can shoot .223 in a 5.56 weapon. A lot of AR’s such as our Wyndom HBC are marked for both.
Yes, of course you can. If it’s marked .223 it almost certainly to be US manufactured commercial soft point ammo. If its marked 5.56, it probably European and/or military ammo. I’ve used them both for years in sporting and military-type rifles. No problema.
Don’t shoot 5.56 unless your rifle is stamped on the barrel for it. 5.56 develops greater chamber pressure than a .223.
Here’s a rather definitive answer from the very experienced and knowledgeable Gun Blue:
Use of 5.56 NATO in 223 Rem. Chambers - “Finally, “Can I Use 5.56 NATO in My Mini-14?”
My recomendation to you is to not, repeat, DO NOT rely upon any advice from anyone online, including but not limited to this forum. Pick up a handloading manual, they are easy to get, start a process of educating yourself. The reality is there is very little difference in the ammunition you are discussing.
” Can I use them interchangeably? “
Nope! Nein ! Non !