Ar-15 .223/ 5.56 Question


March 17, 2008, 07:03 PM
I recently purchased a Colt AR-15 heavy barrel match target rifle. Although the receiver is marked .223, the barrel says 5.56 Nato, Heavy Barrel match Target.

I don't like to mix 5.56 in a .223 rifle. Do I follow the receiver imprint or the barrel imprint? Can I use both in this rifle? Any input is appreciated.


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another okie
March 17, 2008, 07:12 PM
You would think the barrel would be the key factor, but I'm willing to let an expert overrule me.

March 17, 2008, 07:13 PM
Unless I'm wrong here, (I've been wrong before, but I'm pretty sure on this one) I would go with the barrel stamping. If the barrel is made to take 5.56 then it'll handle .223. is the best place to fiind out info such as this. Enjoy your new toy! It'll probably be the first of many. :D

March 17, 2008, 07:25 PM
What we need is a double-blind study... I'm guessing that most people will never be able to tell a difference... Chrony and a bullet puller (to ensure that we're comparing identical weight rounds) should tell the tale.

March 17, 2008, 08:50 PM
the general consensus as far as i can tell is that its fine to use .223 in a 5.56 gun (the barrel is where the chamber is, and the chamber is the important part in this regard) than it is to shoot 5.56 in a .223 chamber. 5.56 is loaded to a little higher pressure than most commercial .223. your rifle will handle either just fine and dandy. 5.56 is often cheaper because you can find military surplus but if you want to use match ammo, you'll pretty much be stuck with .223 as there isn't a lot of 5.56 match ammo out there. again, yours will be fine with either.


March 17, 2008, 08:51 PM
Go with the barrel stamping, more info here

March 17, 2008, 09:10 PM
I can't tell the difference I have put m193 and 223 cheapo ammo through the guns I have they cycle fine and feed fine and accuracy depends on whether or not I am having a good day.

Depends mostly on the bullet type and bullet weight.

Zach S
March 17, 2008, 09:14 PM
You go by the stamp on the bbl, since the chamber is part of it.

You can shoot either in it. Mine is chambered for 5.56 and normally eats .223.

If its a 1/7 twist gun stay away from the lighter ammo (less than 55 grains) and you'll be fine. Well, you'll still be fine with lighter ammo, but the rifle may shoot patterns instead of groups.

March 17, 2008, 09:35 PM
My Colt Match Target is marked the same as yours, and it is chambered for the 5.56 round. If you have the 1/7 twist, Zach is right, stay away from the lighter bullets.

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