Cupcake

I only recently learned that there was even a difference between the two. Which is more readily available and which is more affordable? Any other reasons to choose one over the other?

Thanks,

Lloyd

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Redneck Repairs

If at all possible get a 556 its all the same till it isnt . both can be safely fired in a rifle , but the 5.56 is just a bit different . a match .223 can fire a 5.56 tho you will have stopages like lost primers ect ... . a 5.56 chamber will fire . 223 all day with no harm other than accuracy . Rock river preports to fix all the issues with thier " Wylde " chamber , I dont know , but for me on auto its a 556 and on a bolt where i trim cases ect.. its .223 .

azchevy

Get 5.56 The 5.56 chambers are made for high pressue and can fire both.

The .223 are not and I would not fire 5.56 in a .223 chamber

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P95Carry

RR is right IMO - but I'd add, don't go other ways around.

NATO ammo thru a good .223 Rem can be less than ideal - same pretty much as putting sloppy tolerance 7.62 thru a good .308. - plus the pressure deal.

Another thing too - maybe in a crisis the mil 5.56 will be in greater supply/available but the .223 will still do.

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Sig 210

Many current makers do not differentiate between the two. Most of my guns are .223. i do not notice any difference when i use military ammunition. No stretching of cases, no problem with primers, nothing. There used to some difference in the .223 SAAMI chamber dimensions and the 5.56mm chamber dimensions. Think the difference is in the leade. i've miked the case lengths and everything else.

The best groups that i have ever fired were TW 67 military ball in my Handi-rifle and my Encore: 1/4 inch, 100 yards groups are not unusual for these two guns with that ammo. The owner's manual for the Handi-Rifle specifically states not to fire 5.56mm ammo in that rifle.

Have a new left hand Stag Arms AR-15. Have shot it with re-loads, Winchester .223 and military ball, no problems with any of it.

Conclusion, it ain't a big deal.

Sig 210

There are many facets to the .223 vs 5.56mm chamber situation. i'm not sure that anyone today chambers AR-15 rifles to the original 5.56mm military dimensions.

There are those experts who will tell you that the military cases are thicker. Weighed thousands of civilian and military cases and can tell you that this is not so. Always weigh my cases the first time they are re-loaded and segregate them by weight for accuracy. The link below bears that out.

It is true that some, mil-spec. 5.56mm should not be used in a .223 Match barrel. It is also true that some civilian .223 ammo should not be used in a tight Match barrel.

High pressure is caused when a bullet is shoved into the lands of a rifle. When i reload for real accuracy, i like the bullet about 5-10 thousands of an inch off the lands. The bullets of 5.56mm military ammo is well off the lands of all my .223 guns. Probably not so in a Match chamber.

Here is a link that has chamber dimensions and other good stuff.



http://www.ar15barrels.com/tech.shtml

Cupcake

Thanks Guys. A friend of mine thinks I know everything about guns, which is so far from true. Anyway, I'm going with him to the gun store later and wanted at least to sound reasonably intelligent.

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sisco

http://www.winchester.com/lawenforce...spx?storyid=11

http://www.thegunzone.com/556v223.html

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Sig 210

"The 5.56 cartridge case may have thicker walls, and a thicker head, for extra strength. This better contains the higher chamber pressure. However, a thicker case reduces powder capacity, which is of concern to the reloader."

I've weighed and miked thousands of 5.56mm cases by over 20 different manufacturers and have found this not to be a true statement. i would expect such a statement from a US ammo maker.

Cupcake

Thanks again, Guys. Took my buddy to the gunshop and he ended up with a S&W M&P AR15. The reciever is stamped .223 and 5.56. Now I really want one. Really.

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