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View Full Version : 223 vs 556 debate, need help


sfguyhere
02-26-2010, 11:56 PM
So, here's the deal. I'm looking at getting a Colt LE6940 in 223. I know you're not suppose to shoot 556 in it because of the headspace, etc... but, there isn't a decent 556 at the great price I'm getting.

Also, I don't really want a 556 because of the loss in accuracy with 223 ammo and i'd be shooting mostly 223 ammo anyway with little 556.

I'm under the impression that the Colt 223 would hold up to occasional 556 ammo?

Is there anyone in my situation that can help?

Thanks ! ! ! ! ! ! ! !

Josh3239
02-26-2010, 11:57 PM
The Colt 6940 is a 5.56mm, it can do both. Not being able to use 5.56mm in a .223 has nothing to do with headspace, it has to do with higher pressures and a different leade.

http://en.wikipedia.org/wiki/5.56x45mm_NATO#5.56mm_NATO_versus_.223_Remington

sfguyhere
02-27-2010, 12:04 AM
Hi Josh,

Thanks for the info... The receiver did have 223 stamped on it. You think it's still a 556?

FMJBT
02-27-2010, 12:18 AM
What does the barrel have stamped on it?

Barney Gumble
02-27-2010, 12:19 AM
It's 5.56. The stamping on the receiver doesn't tell you what the chambering is. The chambering is on the barrel. If you look at the barrel towards the muzzle end it will be stamped something like "C MP 5.50 NATO 1/7".

Btw before you order, check with your FFL to make sure he'll accept a 6940. It has the same rollmark as the 6920, which is banned by name, so some FFLs won't do it.

Josh3239
02-27-2010, 12:27 AM
Receiver markings are for the most part just to keep the feds happy. Actually most of the newer receivers are marked "multi" since the AR is so modular. One of my ARs is 5.56mm but is marked as "multi", another is 5.56mm but marked ".223" and my last one I believe is marked ".223" but is actually 9mm. I have a 9mm conversion barrel for my .40S&W marked Glock 23.

But back on topic, I'd be surprised if Colt makes an AR that isn't 5.56mm.

Hi Josh,

Thanks for the info... The receiver did have 223 stamped on it. You think it's still a 556?

sfguyhere
02-27-2010, 12:30 AM
You guys rock ! ! !

Thanks for the info... The rifle is a 6940 and feels awesome. It takes to the shoulder like a well used S x S... I will have to get an AIM point for it as the flip sights are made for long distance shooting.

1*mike
02-27-2010, 12:32 AM
Hey sf guy did it come n pink or did you paint it yourself. Fabulous

sfguyhere
02-27-2010, 12:37 AM
LMAO ! ! !

Dude, the 223 / 556 did not occur to me until I was at the station, putting in my request for a department letter with my receipt in hand...

maxwellca21
02-27-2010, 12:39 AM
Also, I don't really want a 556 because of the loss in accuracy with 223 ammo

is this really true? can anyone verify this because im curious about this also.

sorry for the thread jacking.

1*mike
02-27-2010, 12:39 AM
The tactical glitter blinds the zombies

sfguyhere
02-27-2010, 12:42 AM
Hey Maxwell,

I got the info from a few sources and am including a link to one of the other forums... Maybe a resident expert could add more info?

http://www.ar15armory.com/forums/556-223-Ammunition-Ch-t22582.html

Josh3239
02-27-2010, 12:48 AM
Again, I believe this has to do with the difference in leade.

is this really true? can anyone verify this because im curious about this also.

sorry for the thread jacking.