[G Larry]

OR, you could do your own forensics and determine the actual specs on your weapon!

[ReverendJames]

So how does impact a Ruger Mini14? The military stuff is cheaper. Best not use it in that rifle?

[SIDENET]

Get an AK variant chambered for 7.62 x 39.

Problem solved.

[Georgia Girl 2]

Yes if its marked .223 it is dangerous. If its a bolt action marked .223 a 5.56 is totallly dangerous and overpowered. An M-4 which is a 5.56 but will take a .223 is a different situation.

[hemogoblin]

This is surprising; I have always seen them presented as interchangeable. This is a great site that lists them together ...

[50cal Smokepole]

Both my AR uppers are 5.56. The Rem .223 ammo is not as accurate out of them as the NATO stuff. No surprise there. I chose 5.56 because I can safely shoot the .223. I reload the NATO brass for varmint hunting and knocking the paint off the gongs at 300 meters.

[rsobin]

If you reload , load to max. OAL. This will lower pressures significantly.

[SuperLuminal]

Hmmmm...

[Chode]

.308 there's no substitute...

[Pontiac]

I have 2 AR-15s and never fired anything other than surplus ammo.

I have never had a problem in either rifle.

[E. Pluribus Unum]

Q. Can you shoot 5.56 mm ammo in Ruger Mini 14?

A. Yes you can, the Mini 14 has always had a 5.56x45 chamber.

The mini14 receiver is marked ".223 CAL" not ".223 rem."

[phockthis]

sfl

[Cobra64]

I did my homework on this before I bought my AR15 in 5.56.

To the novice, the two rounds look identical.

[org.whodat]

LOL, when you start worrying about the thickness of the copper/brass you have a problem but it has nothing to do with the firearm. LOL

[musicman]

BFLR

[smokingfrog]

For an AR-15 it doesn't matter what the RECEIVER says.

Check the stampings on the BARREL.

Rock River Arms is known for using the Wylde chamber in their varmint rifles.

AR15 Chambers (pdf file)

[Mat_Helm]

Pretty simple, just trim your cases to specification to be sure you have no head space problems and work your loads up before trying to go for maximum velocity and watch for pressure problems before they occur. You can also check for case internal volume by measuring before you reload your cases to look for case wall thickness affects before setting up your specific load. I have found that the commercial Winchester brass loads pretty much the same as their military brass and the same as Lake City brass. Stay away from the Federal brass.

[stevie_d_64]

bump

[flowerplough]

“It is our understanding that commercially available AR15’s and M16’s – although some are stamped 5.56 Rem on the receiver – are manufactured with .223 chambers.”

Knew something like that was coming, was surprised how far down the page I had to read to find it.

Basic rule of precision consumer-market manufacturing: Do whatever’s cheapest or easiest, eh?. How many of our technologically/numerically illiterate customers are gonna discover or understand the difference?

[CholeraJoe]

My original Colt AR-15 is marked .223, but I know it will shoot 5.56 NATO rounds easily. I’ve put several thousand through it including ball, SS-109 and tracer.