.223 or 5.56


September 2, 2009, 11:40 PM
Getting another AR, maybe a DPMS, but all of the info I have seen on them say they are .223

Is it safe to fire 5.56 out of them or is that 5.56 out of a 223 crap just that, a bunch of crap

Also, side note that grinds my gears; looking for AR uppers online, want to build a lower and buy the complete upper, all the makers have something about DUE TO THE LARGE VOLUME OF ORDERS EXPECT A 10 TO 14 WEEK WAIT, but when I walk into any gun store they are lined with ARs. Just not with what i want for what i want to pay

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September 2, 2009, 11:50 PM
go to gunbroker and get a stripped lower off of there...for parts kits try Midway or Military Gun Supply...dependin on what part of TX your in you may be able to go by Military Gun Supply's store...its in DFW if I'm not mistaken...

My DPMS AR upper said it was a .223 upper when I ordered it but when I looked at the underside of the barrel, it says 5.56...just wait and see what your barrel is marked...

September 3, 2009, 12:04 AM
SAME ROUND by all accounts in NEW guns....

September 3, 2009, 12:24 AM
SAME ROUND by all accounts in NEW guns....

5.56 is slightly different dimensionally and is a higher pressure round.
You can shoot .223 out of a 5.56 chamber or a Wylde chamber, But for 5.56 you want a 5.56 chamber or wylde chamber.

September 3, 2009, 12:44 AM
and I suppose a 7.62X51 NATO cannot be shot through a .308 either.... Whatever... IF for some strange reason I cannot find any .223 for my AR, then you can be damned sure that I would have no reservations about shooting 5.56 through it instead....

though I Cannot fathom being able to find 5.56 and not being able to find .223...Therefore I wont be dwelling on this "issue."

September 3, 2009, 12:44 AM
It doesn't matter what the lower says whether .223 or 5.56 all the action takes place in the upper. DO NOT use 5.56 in a .223 barrel! It's ok to use .223 in a 5.56 barrel though. Or if you have a Wylde barrel which can handle both. Yes the 2 cartidges are almost virtually identical in size and performance BUT the 5.56 NATO round is different from the .223 sporting round that it produces higher pressure in the rifle.

I am not an expert reloader or a technical genius but SAMMI (Sporting Arms and Ammunition Manufacturers' Institute) states that "rifles chambered in .223 to NOT use 5.56mm Military, 222 Remington, 30 Carbine."

The big difference here is that "chambers for military rifles have a different throat configuration than chambers for sporting firearms which, together with the full metal jacket of the military projectile, may account for the higher pressures which result when military ammunition is fired in a sporting chamber."

"NATO chambers have a long leade (the distance the projectile of a chambered round must travel upon ignition before it enters the bore of a barrel) . SAAMI chambers are tighter and have a short leade. SAAMI chambers are designed for increased accuracy, but will yield dangerously high pressures in guns using military ammunition and/or which are subject to high volume shooting. Under such high pressures, a primer may back out completely, drop into the action and cause the firearm to stop working." which means it can cause MAJOR jamming or ruin your rifle. Extremely dangerous.

Yes many rifles chambered for .223 have fired 5.56 flawless for decades... buuut there is always that small chance that if it does finally give in to too much pressure in too short of a throat.. well this could stress it and weaken it over time. Just use the 5.56 barrel.

September 3, 2009, 10:03 AM
Simply stated:

1. There is slop (extra long leade or free bore) in a 5.56 chamber, that does not exist in a 223 chamber (supposedly, although some manufacturers, Ruger for example, make no distinction).

2. 5.56 Ball uses a thicker case (most any Ball ammo does since self loaders are hell on cases), meaning less case capacity, meaning a higher density charge and/or faster powder to get the rifle to function.

3. Therefore, shooting 5.56 Ball in a 223 chamber will result in higher peak chamber pressure, since the bullet engages the rifling sooner. In a semi-auto, which is designed for a particular pressure curve to operate normally, this will lead to accelerated wear. In any type of action, there exists the potential for throat erosion, although the 223/556 case in not particularly overbore, but a semi-auto can cycle more rounds than a bolt gun, adding heat faster to the chamber throat.

4. In conclusion, AR clones are VERY expensive. Therefore, use the ammo your gun's manufacturer recommends to protect you, your investment, and your standing under your warranty.

September 3, 2009, 10:08 AM
My son is a AR15 fan and he says watch the twist of the barrel before using 62 grain. And he said there is a difference between 5.56 and .223..Don't know. I don't care for them. Saw them up close and personal in VN. My weapon of choice is the AK.

September 3, 2009, 10:16 AM
Personally, I'm with the crowd that believes that there is a difference, no matter how "slight," between .223 and 5.56.

However, when I called Centerfire Systems last fall about my pending Doublestar, the woman I spoke with in sales said "There's no difference between [the two]." When I said something about there being a pressure differentiation between the two, she said "don't worry about it in civillian application." I guess the thought is if you were running hundreds of rounds a week, i.e. combat patrol, it might do something; but for normal range and hunting, not an issue.

Nevertheless, I was relieved when mine arrived stamped 5.56.


September 3, 2009, 10:29 AM
Split the difference. 556 in a 223 bolt gun only, otherwise use manufacturers recommendations.

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