Home Forums Hunting & Shooting AR and Tactical Rifles AR in .223 Rem or 5.56 NATO

OK, I am a little confused. I realize that there is a little bit of difference in the two cartidges but I am curious to hear real world experience.

What I (Think I) know.....
.223 Rem- less head spacing from the lands and groves (smooth bore chamber area shorter)Should not shoot 5.56 NATO rounds due to the higher pressures
5.56 NATO - More space for a longer OAL or longer bullet seat enabling a bit more powder and therefore higher pressures. Rifles chambered in this configuration can shoot 5.56 NATO as well as .223 REM.

Here is where you guys come in...

I would think that with these things taken into account someone would ALWAYS purchase a rifle chambered in 5.56 NATO.... However, it seems that standard .223 Rem ammo, being slightly farther away from the rifling, obtains less accuracy than the 5.56 NATO rounds in the same tube....
Up until now, I have considered these two rounds to be interchangeable BUT..... It seems that this is not the case.

Your thoughts or comments?

I am in the market for my first .223 AR and thought I would get some input. In some ways, what I read is as "clear as mud." I currently have a .223 REM bolt gun that eats anything I put in it and shoots them all well.

Gosh what a new and innovative question. Has it been a week already?

The search feature is there for a reason. Here is a link to the latest iteration of this question.

http://24hourcampfire.com/ubbthreads/ubbthreads.php/topics/5839528/1/AR_15_questions

5.56 in AR and 223 in a Bolt Gun

Thanks for the link. I tried the search function but never seem to get it to work very well on this site.
Thanks for taking the time to complain and then reply.

I was asking for real world results rather than what I found on internet search such as how a .223 round performs relative to a 5.56 round in a 5.56 AR. I read that .223 will be incosistent in the 5.56. I am guessing that based on the other, less pissy reply, I will be well suited with a 5.56 AR even though my current bolt gun is a .223...... I want the AR for plinking and range fun. That is why I asked about PERFORMANCE, not whether you should or could use certain ammo as I already knew that answer. I will not be shooting long range or shooting for tight groups as my bolt gun already handles that very well. I am guessing that .223 REM ammo will be "good enough" for my intended purpose in a 5.56 chamber AR.

Thanks again.

On second thought... what I should have asked is....

Why in the *%$#! would anyone buy a .223 REM chambered AR and not a 5.56?

There is no reason to buy an AR specifically chambered in .223 Rem. The "best" chamber to get is a hybrid like the Wylde chamber or similar from any number of vendors.

A rule of thumb is any barrel with a 1:9 or faster twist is most probably a 5.56 NATO or hybrid chamber.

You're quite welcome.

I have read a little bit about the Wylde and will doa litle more research. Now I just need to see what options are out there in that configuration.

I got the AR bug the last few months and it is pretty bad. 2011 was a new bow and that sure added up the $$. Now with the AR platform, there is a new and/or cool accessory around every corner.

Might be a bad thing.

I wonder if your 223 chambered AR would have a problem if you repeatedly fired any of those silly surplus 5.56 NATO rounds for which a plethora exists floating loosely about the country and for only $300/1000. Naw no worries, carry on...


but the reverse can be an unsafe combination. The additional pressure created by 5.56 mm ammo will frequently cause over-pressure problems such as difficult extraction, flowing brass, or popped primers, but in extreme cases, could damage or destroy the rifle. Chambers cut to .223 Remington specifications have a shorter leade (throat) area as well as slightly shorter headspace dimensions compared to 5.56 mm "military" chamber specs, which contributes to the pressure issues.

I've got a tight chambered Bushmaster CMP rifle that blows 5.56 primers every time.

A Wylde chamber is a much better option.

Wylde chamber will give you the best of both worlds, although a 5.56 NATO chamber will shoot when properly fed.

I have a 5.56, and my uses / needs are similar to yours: "Plinking and Range Fun" I use the green tip AND the .223 American ammo. Some of the cheaper Milsurp ammo has worked (Silver Bear does great) and some doesn't work for me at all (Herters steel cased for example.)

Either way, for your intended purposes, my suggestion is to go 5.56 and shoot whatever will cycle in your weapon. You'll have fun, and nothing to worry about.

My AR chamber marked .223 will not exract 5.56. Takes a cleaning rod to get them out.

Regarding your bolt gun, Remington issued a warnig 20+ years ago that it would not honor warranty on any of its .223 guns fired with 5.56.