caliber question

[Argonnakid]

The Nosler manuals have a different area for both the 5.56 and the .223 rem. .

 

[Stebo]

nymike,

Is this the rifle that you struggled to get the barrel nut loose on, finally machined it off? You thought it had been pinned, did you determine that to be true? The upper would have some hole drilled in it, probably in the threads. Just curious. Wondering if S&W went that extra step to insure that model was compliant and could't be readily changed. That might explain the 223 barrel. Also, what FF did you install?

 

[nymike]

yes same gun, reasons could all be linked

 

[lhump1961]

My understanding is that the .233 and the 5.56 are basically the same with a few exceptions from the "sporting" .223 to the "military" 5.56.

-the leade (throat) space is longer (SAMMI specs) on 5.56 to accommodate a longer OAL sometimes found in military 5.56 ammo.
-the brass on a 5.56 is slightly thicker than on a .223 thus the variations you will see in loading data.

I would be wary of firing 5.56 ammo in a .223 because of the risk of running a bullet up against the rifling in the barrel...not good! BUT, having said that you can find lots of info stating that you can fire either in a .223...I'm not sure I would do it as the 5.56 ammo will run at a higher pressure in the true .233 from lack of head space and leade.

now can i reload 556 brass to 223?
That should be fine but I wouldn't load .223 to 5.56!

Most AR type rifles are chambered to handle both but when in doubt a phone call to the manufacturer is needed to be sure.

 

[oneyeopn]

I load .223 brass to 5.56 data all the time...on the powder I use the difference is .1gr. No pressure signs no problems with the brass and some of it is on its 4th and 5th reload with no problems.

 

[Argonnakid]

To my understanding, the OAL. as listed by SAAMI for both the 5.56 nato and the .223 rem. is 2.260. The reasoning for the different leade is with the thicker casing in the 5.56, the case volume is reduced. This causes a higher starting pressure. The leade is slightly, just slightly longer in a barrel chambered for 5.56 to give the bullet alittle more time(microseconds) before it contacts the rifling of the bore. This gives the pressure time to drop down some. As far as the headspacing is concerned, there is no difference between the two. The case dimensions are the same exact. These rounds headspace on the shoulder of the case. I hope this is useful information for you.

 

[REM 3200]

Take it to a gunsmith and have him run a 5.56 chamber reamer in it and you are good to go.

 

[shawn mccarver]

ok guys, got a question, im pretty sure i know the answer to but i wanted some reassurance. while working today i happened to pass a store and a smith and wesson dealer sign caught my eye, so i stopped to see if they had any 223 in stock, well they guy says sure here ya go, and hands me boxes that say 556, and i said oh no good i got a 223, you cant shoot 556 out of it. so he asked me what kind of gun, m&p15 i said. so he says its a 556, i told him it says 223 right on the barrel not 223/556, he said i think your wrong, i knew i was right, and he said either way ALL smiths are chambered for 556 so you can shoot 556 no matter what the barrel says.... now i think thats dead wrong, if it could handle 556 it would say 556, am i wrong? my gun says 223? if this guy was wrong he definatly is giving info to people that could be potentially dangerous?

You probably have a "compliant" rifle, and I understand those are marked for .223 to avoid the whole "military cartridge" thing that seems to cause so much heartburn among certain types of people.

The real question then, is whether S&W actually chambers all rifles the same, and just marks the compliant ones differently; or, whether they really are chambered differently. S&W will probably tell you to shoot only that ammo for which it is chambered as marked on the barrel.

The reason for this is that there are differences in the dimensions of the chambers of the 5.56 and the .223. I believe the general rule is that you can shoot both in a 5.56 chamber and only .223 in a .223 chamber. I recall an article years ago, however, in which Ruger (maybe Bill Ruger himself) was bragging (and justifiably so) about the strength of his Mini-14, and he said that the Mini-14 would handle the 5.56, no problem.

That said, I would follow S&W's advice. Your only other option is to take it to a VERY reputable gunsmith and have the chamber checked to be sure of what dimensions you have in your rifle. Short of that, use the ammo shown on the barrel.