.223 vs 5.56

[50calshooter]

OK there was a thread similar to this question but more based around the M&P15 rifle.... I didn't get a definite answer/opinion on this. What is more questionable, shooting .233 out of a 5.56 rifle OR shooting 5.56 out of a .223 rifle? When I say questionable I mean, dangerous/harmful to the rifle. OR are they both risky either way? I don't mean to belittle this issue but I think a solid discussion on this will benefit lots of shooters on this board, me included... Thanks guys,

 

[pierrody]

From the Winchester website:

You can fire .223 Rem cartridges in 5.56mm chambers with this longer leade, but you will generally have a slight loss in accuracy and velocity over firing the .223 round in the chamber with the shorter leade it was designed for.

Problems may occur when firing the higher-pressure 5.56mm cartridge in a .223 chamber with its much shorter leade. It is generally known that shortening the leade can dramatically increase chamber pressure. In some cases, this higher pressure could result in primer pocket gas leaks, blown cartridge case heads and gun functioning issues.

(Original article here: w ww.winchester.com/lawenforcement/news/newsview.aspx?storyid=11)

 

[redleg]

I am pretty sure that most manufacturers don't have seperate reamers for each barrel except for the higher end custom or match stuff. They use a standard one for all their production and simply change barrel roll marks to keep the State Dept happy. I also believe that the 223/556 interchagebility issue is over stated by SAAMI. I have yet to see the equivalent warning issued by CIP and in fact most European production ammo is labeled 223 Rem / 5.56mm Furthermore there are cartridges in production that meet neither of the SAAMI specs. RUAG GP90 is one. Is is military ammo, made to CIP chamber specs and yet marketed for 223 Rem rifles. RUAG apparently has no safety concerns with this combination.

 

[CDNbear]

same story as 7.62 V 308 ??

 

[Power Pill]

I didnt know there was a difference

 

[tjhaile]

The CIP pressure standard for .223 is the same as for 5.56mm NATO. The SAAMI pressure maximum is different because a different method is used to test pressure.

http://en.wikipedia.org/wiki/223_Remington#.223_Remington_versus_5.56_mm_NATO

http://en.wikipedia.org/wiki/NATO_EPVAT_testing

Hypothetically, 5.56 ammo fired out of a tight match type chamber might develop unsafe pressures. For the most part, I doubt this is a problem. I have never heard of a kaboom from shooting 5.56 out of a .223 chamber.

 

[greentips]

same story as 7.62 V 308 ??

It is another way around - my understading is that, which I could be wrong, 308 operates at a higher pressure than 7.62 NATO by spec. Some of the older battlerifles are designed around down powered ammunition.

 

[Onagoth]

Just curious, how many people shoot .223 out of their 5.56 chambers.....I am under the impression that .223 is far more readily available, but that many, if not most, ARs come chambered in 5.56

 

[Tuco Pike]

Just curious, how many people shoot .223 out of their 5.56 chambers.....I am under the impression that .223 is far more readily available, but that many, if not most, ARs come chambered in 5.56

I would guess most, since finding actual 5.56 ammo is very difficult not to mention a lot more expensive. Both of my colts are marked 5.56 and I don't think they have ever seen a real 5.56 round in their lifetimes, unless they were test fired by colt with it.

 

[crashcollins]

I tend to shoot whats on the barrel. But lately due to US export restrictions Mfg's are marking their barrels as 223 Rem. when they in fact have 5.56 chambers. Be safe and ask the Mfg. what is safe to shoot in your rifle. All of my rifles are able to shoot 5.56 and are marked as such except for the XCR I just got today. The XCR is marked 223 Rem. but is able to shoot 5.56

 

[brewmech]

I was always under the impression that both .223 rem and .308 win were around before 5.56 and 7.62 NATO. These cartridges were adopted and designated accordingly in there metric class. The pressures may be different but the cases are the same. I have measured military(metric) and hunting rounds with mics and the difference is insignificant. As far as chamber pressures , I don't think there is enough of a difference to worry when using in a modern firearm.

 

[Scharfschütze]

I have measured military(metric) and hunting rounds with mics and the difference is insignificant.

I came to the same conclusion. The .223 is only .004" larger in diameter than 5.56. Very insignificant in my mind. I would hesitate to shoot 5.56 in a .223 chambered rifle but that's just me.

 

[mosquito99]

the conversion factor is .o3937. so 7.62X .03937= .299994 and 5.56X.03937= .21889.
its not .004 its less. just looking at the number the metric is smaller, just !!!.

 

[Tom_Swift]

If it's a milspec platform gun shouldn't it be able to fire 5.56 and they just put .223 to get past export restrictions.

 

[Grizzlypeg]

Is there a reason why all the rifles aren't chambered in 5.56 (other than recent export regs)?

 

[mosquito99]

i think its a nato requirment, ISO manufacturing, and with ISO everthing is metric. not 100% sure

 

[Grizzlypeg]

The whole thing is just about a practical as Whitworth wrenches.

 

[brewmech]

I agree grizzlypeg i worked in a paper mill, whitworth wrenches really are useless.

 

[jennis]

In this the internet age, where people will film seemingly anything ending up on 'youtube' and 'liveleak', feel free to post 'links' of mixing and matching gone terribly awry

Truth be told my one 700P shoots 762 'nato' better than the bulk #### offered in 308 winnie, my other 700P will also throws out 556 all day long, as far as my semis some are marked 223 others 556 I mix and match like Rosie o'Donnell at a 5.00 buffet......

 

[TGC]

To make it easy, are your firing military ammo or civilian ammo, and they both will work, like one poster said, 308 or 7.62, both the same, military has a bigger kick, and civilain casings might be different. go shoot have fun.