.223 remington versus 5.56 x 45 mm NATO - is it safe to interchange???

Yehen said:
I'm pretty sure they're just refering to the higher pressure 9mm nato rounds. They're pretty much 9mm +P+. Most newer guns should be fine with them though.
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You missed the sarcasm....easy enough if you don't know me.
I was highlighting the 9mm nato v. 9mm luger as a case in point to the pure nonsense put out on SAAMIs part.
I think if you look at nato cut chambers for both the 7.62 and 5.56 they are done that way to ensure reliable operation in fully automatic and under adverse conditions - not because the ammunition is necessarily higher pressure...
Tiriaq has said it best; the testing is apples to oranges....Personally I think most of it is over blown CYA on SAAMI's part...admittedly a justifyable position to take considering the position they are in.

Yehen said:
Most newer guns should be fine with them though.
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...and the Browning High Power that has been in service since 1944?:jerkit:
 
Well I must be tempting fate. As it turns out since my first of 130 gun I bought since I was 17 (now 41) I have logged every guns use at the range and woods. An ammo odometer if you will. Some 14 of them of 223 or 5.56. from hunting tikkas, remingtons, savages etc to colt and armalite ar15 platforms. In total just short of 78,000 rounds fired. When I chose a round to use in each of them the only thing I gave a thought of was bullit wt for the twist if it were a 1/12 barrel. In all that time with all that shooting I have never had anything pop. I have all my fingers,eyeballs,and teeth. The rifles are all fine. and even the fast 1/7 twist barrels never once made a varmit bullit explode leaving the barrel. You know I think people are always going to have this discussion for decades to go. I will likely be there decades from now to be living proof that it is safe.

Flame on

Moe
 
I find that 762 'nato' in my 700P ( 308 ) is more accurate than a lot of commercial 308


PS....What weighs more a pound of feathers or pound of sand , exactly they are the 'same thing '
 
Just so your #### dosen't fall off, this is from the Armalites web site tech notes.

P.O. Box 299 Geneseo Illinois, U.S.A. 61254 Tel 309-944-6939 fax 309-944-6949 info@armalite.com
August 17, 2009 Rev 0

TECHNICAL NOTE 74: 5.56 NATO vs SAAMI .223 Remington vs Wylde
Chambers

BACKGROUND: We are often asked about whether our rifles feature NATO (NorthAtlantic Treaty Organization) or SAAMI (Small Arms and Ammunition Manufacturer’sInstitute), or Wylde chambers and whether it makes any difference.

FACTS:
.223 Remington (SAAMI standard) and 5.56mm (NATO standard) rifle chambers are almost identical. The difference is largely limited to the “freebore”, the cylindrical space in front of the casemouth, and the “lead” or “leade”, the tapered region that eases the bullet into full engagement with the rifling. NATO and SAAMI cartridges can normally
be used interchangeably with no problem.

The SAAMI chamber incorporates less freebore and a tighter leade, which normally provides better bullet-to-chamber fit and, therefore, better accuracy than the NATO chamber. It is wonderfully suited to match bullets.

Millions of rounds of NATO ammunition have been fired safely in Eagle Arms and ArmaLite’s® SAAMI chambers over the past 22 years. Occasionally a non-standard round (of generally imported) ammunition will fit too tightly in the leade, and resistance to early bullet movement can cause elevated chamber pressures. These pressures are revealed by overly flattened primers or by powder stains around the primer that reveal leaking gasses.

The first few rounds of ALL ammunition, from whatever source or lot, should be checked for signs of pressure or any other defect before firing large quantities.

If you have a problem, you can generally bet that the ammunition meets neither SAAMI nor NATO specifications.

ArmaLite® has adopted a practice of using a modified SAAMI chamber (Wylde) in its stainless steel match barrels. This chamber is better for match use than the NATO chamber, but fires the NATO ammunition perfectly. We use the NATO chamber in all moly (phosphated) and chrome-lined barrels.

NOTE: ArmaLite’s® larger AR-10 series rifles are all chambered with 7.62 NATO chambers. .308 Winchester (SAAMI standard) ammunition functions perfectly in the 7.62 NATO chambers.
Copyright 2009 ArmaLite, Inc. THE WIZ
 
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roberti11 said:
Look here..
http://www.303british.com/id36.html
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I'm gonna say that SAAMI makes not mention of it because it is a non-issue. I took a look at that guys website, and he seems a little bit over-paranoid. In fact, he reminds me of one supervisor from work, the whose wife even refers to him as "worst-case scenario". One specific thing that I can point to is where he says: "Military brass is thicker. It needs to be. It was made to function and stretch in a wide variety of firearm chambers. Don't forget that the condition of spent brass is of no importance to the service. Like 99% of military brass, it won't be reused." If that's the case, then why was there a huge ruckus raised in the States when the Department of Defense decided to start requiring all used brass to be mutilated as a condition of sale? That got changed in less then a week, and that's the reason why .308 hasn't shot through the roof even more in price. Check Wikipedia on 7.62X51 NATO, and in the first couple paragraphs the address this specifically, with the reference being SAAMI. I'll shoot either through either and not worry at all about it.
Also, as a side note, the reason he was having issues with his reloaded brass not feeding properly is because he probably didn't use a small-base die. It's no big deal on a bolt gun or a lever gun where you can muscle past any small difference in case to chamber size, but if you're gonna reload for a semi-auto you need to use a small-base die to get proper feeding.

Carson
 
hey, this may have been mentioned already, but I was speaking to my local gunsmith, and he said no problem to interchange the .223, and 556 nato. The difference lies within the casing. The nato I believe is made with heavier brass so the interior dimensions are different from that of the .223, but not the outer. Anyone out there confirm or deny?
 
HeavyT said:
hey, this may have been mentioned already
[...]
but I was speaking to my local gunsmith, and he said no problem to interchange the .223, and 556 nato.
[...]
The nato I believe is made with heavier brass so the interior dimensions are different from that of the .223
[...]
but not the outer
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1) it has, read the thread or one of the many others.
2) your gunsmith is wrong, and giving advice that may be dangerous.
3) typically correct (although it varies with brand), so work up your loads if you're using surplus 5.56 brass
4) the external dimensions are essentially the same, it's the chambers and pressures that are different.
 
Whoa! Confusing for a newbie.

Thinking of buying an AR-type rifle from either Rock River, LMT, Stag... Should I be looking for a 5.56 versus 223? 223 doesn't sound safe...

Another question: Does the safety issue compound when dealing with manufacturer such as Norinco?
 
milk said:
Should I be looking for a 5.56 versus 223? 223 doesn't sound safe...
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As long as you don't run surplus 5.56 (which has essentially vanished from the market anyway), you'll be fine. Just shoot .223. For that matter, although I'm against putting 5.56 in a .223 chamber, lots of people do it without catastrophic results. So not a big worry if you plan to shoot .223 .

Having a 5.56 chamber, for most of us, is just for the cool factor. If cheap surplus ever reappears, it might again be a good thing to have the 'milspec' chamber.
 
I was at the range the other day mixing and matching 308/762 in a Ar10 and 223/556 out of an Ar15 without creating a supernova but I have been doing this long before the internet came along
 
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