7.62 and 5.56 question

shortandlong said:
there is an M14 and an ar 15 in my future
is 7.62 Nato the same as 308 Win? and;
is 5.56 the same as .223 remington ?

Not EXACLTY the same, but if you have a Nato chamber, 'close enough'.

from:
http://en.wikipedia.org/wiki/5.56_×_45_mm_NATO#5.56_mm_NATO_versus_.223_Remington

While the 5.56 mm and .223 cartridges are very similar, they are not identical. Military cases are made from thicker brass than commercial cases, which reduces the powder capacity (an important consideration for handloaders), and the NATO specification allows a higher chamber pressure. The 5.56 mm chambering, known as a NATO or mil-spec chambers, have a longer leade, which is the distance between the mouth of the cartridge and the point at which the rifling engages the bullet. The .223 chambering, known as SAAMI chamber, is allowed to have a shorter leade, and is only required to be proof tested to the lower SAAMI chamber pressure. To address these issues, various proprietary chambers exist, such as the Wylde chamber (Rock River Arms)[1] or the Armalite chamber, which are designed to handle both 5.56 mm and .223 equally well.

Using commercial .223 cartridges in a 5.56-chambered rifle should work reliably, but generally will not be as accurate as when fired from a .223-chambered gun due to the excessive lead.[2] Using 5.56 mil-spec cartridges (such as the M855) in a .223-chambered rifle can lead to excessive wear and stress on the rifle and even be unsafe, and the SAAMI recommends against the practice.[3] Some commercial rifles marked as ".223 Remington" are in fact suited for 5.56 mm, such as many commercial AR-15 variants and the Ruger Mini-14, but the manufacturer should always be consulted to verify that this is acceptable before attempting it, and signs of excessive pressure (such as flattening or gas staining of the primers) should be looked for in the initial testing with 5.56 mm ammunition.[4]



from : http://en.wikipedia.org/wiki/.308_Winchester

.308 Winchester is the commercial name for the military 7.62 × 51 mm NATO cartridge. Two years prior to the NATO adoption of the 7.62 × 51 mm NATO T65 in 1954, Winchester (a subsidiary of the Olin Corporation) branded the cartridge and introduced it to the commercial hunting market as the .308 Winchester. Winchester's Model 70 and Model 88 rifles were subsequently chambered for the new cartridge. Since then, the .308 Winchester has become one of the most popular hunting cartridges available. It is also commonly used for civilian target matches and police sharpshooting. The relatively short case makes the .308 Winchester especially well adapted for short action rifles.

While the .308 Winchester and 7.62 × 51 mm cartridges are generally identical, there are minor differences in their case dimensions and chambering specifications that should be noted. The 7.62 × 51 mm is smaller by a few thousandths of an inch in some dimensions. This can lead to excessive chamber pressures if a .308 Winchester cartridge is fired in a 7.62 × 51 mm chamber. However, the opposite should present no problems.
 
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thanks I heard that, but i heard there were differences in the shoulder ......is it safe to shoot 308 winchester in a norc m14
and what about reloading?
 
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Hundreds of thousands of RG 7.62NATO rounds are fired every year at Bisley England, out of rifles chambered for .308.
Before the NRA UK went to the new RG 155 gr match bullet for competition, plain old RG 144 gr ball ammo was used.
 
How ever did we live through it? Long before there was an internet, lots of shooters used .308 and .223 factory ammo and reloaded using regular FL .308 sizer dies in their milsurp battle rifles and vice versa with no fuss whatsoever. Doing just that has never bothered my semi'd M-14 in the least.
 
shortandlong said:
whoa i wouldn't want to chance it myself, Manyard but what about resizing and reloading to 7.62 and like wise 223 to 556?

Has anyone ever seen 7.62 NATO or 5.56 NATO dies? Not .308 or .223, I mean dies that are marked 7.62 or 5.56 NATO.
If you fear blowing your face off because you are shooting civilain ammo out of a Mil. Spec chamber, have the chamber re-cut.
With all this being said, if you are reloading, a grain or two of powder could also run pressures higher then NATO of SAAMI Specs.
Primers, powder lot, and type of brass and bullet design all change chamber pressure. A load using Win brass will have lower pressure the the same load in an IVI case.
Remember Mil. Spec ammo or Mil Sup ammo is made by the lowest bidder.
 
Has anyone ever seen 7.62 NATO or 5.56 NATO dies? Not .308 or .223, I mean dies that are marked 7.62 or 5.56 NATO.

I was actually wondering just that
hince my education continues:)

If you fear blowing your face off because you are shooting civilain ammo out of a Mil. Spec chamber, have the chamber re-cut.
yes i do not its not pretty but its the only face i have, chamber recut? hmmmn how would that affect the resale value? and are there any accuracy trade offs, what would be the cost and risk?
I think that is a really really good idea though
 
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If you fear blowing your face off because you are shooting civilain ammo out of a Mil. Spec chamber, have the chamber re-cut.
The problem is that military chambers in any multinational calibre as in made in more than one country are made to a set of tolerances. If Canadian Ross rifles in .303 had such perfect match tolerance chambers that would help yo explain why other supplied ammo within tolerance may have jammed. The same in theory applied to 7.62 Nato. The ammo with a cross in circle headstamp means it has been manufactured to a set of tolerances that in this case are covered by a STANAG, (Standardised Nato Agreement) which there are many and one covers link for Machine guns one will cover ammo in such andsuch calibre. When a country builds its rifles or buys them in it has the chance to inspect and use gauges to see if the chambers are in tolerance. If the ammo procured is within tolerance the theory is that all will work well. Both .308 and .223 are the effective civilian versions of the original calibres adopted by the military. However the military wont necessarilly be using the same bullets in their ammo as you get in SAAMI approved federal .308 for your Model 70. That is one issue, also the military ammo evolves and pressures change, bullet weights change as do components. The biggest problem is quality control in both the rifle factories, hence European and UK proof House laws to protect the buyer and should stop defective materials being sold but how do you test each round of ammo without firing it?
More accidents are caused by poorly assembled or incorrect ammo components than badly dimensioned chambers. The Chambers of both military and civilian rifles should fall inside these tolerances but if one is at one end of tolerance and the ammo is at the other then problems can occur.
i usd to work with a motor bike nut who forever talked of blue print porting his engine. In theory almost ackly improving it as mass production left enough to be desired that pushing the limit would improve performance.
If you believe that your chamberwont tolerate 7.62mm ammo then look at the UK NRA rules which were quite strict that all rifles in use had to be in proof not just have passed at sometime. Handloading was prohibited for a long time and Barrels to upgrade your P14 to target rifle were available in 7.62mm Nato which is what .308 was sold in the UK apart from sporting ammo.
For many years it wasnt recognised as anything beyond a marketing pitch by Winchester and to be honest as long as the ammo fits and is within pressure limits for the weapon then it is the right ammo!
 
shortandlong said:
yes i do not its not pretty but its the only face i have, chamber recut? hmmmn how would that affect the resale value? and are there any accuracy trade offs, what would be the cost and risk?
I think that is a really really good idea though

There is a .223 match chamber reamer designed for shooting 69 gr bullets that just so happens to work great with 80 gr bullets. It is called a .223 Wylde, named after the designer, Bill Wylde from Greenup Ill.
I personally don't think a rifle re-chambered with a match reamer would drive down the resale value. OK now, would you rather have a rifle that was chambered with a dull production reamer that just makes specs, or a rifle that was chambered with a nice sharp match reamer?
 
Thank you, I found this thread educational. It also prompted me to check what "caliber" I actually do have, and the answer supprised me even more. I have Armalite 180B and according to them the chambering is 223 hybrid.... What does that mean exactly ?
 
I have a 2007 Z06 Corvette.....Can I use 92 octane from Chevron or 92 octane from Esso.....Wait a minute....there BOTH the same....556/223
762/308:slap:
 
jasiu123 said:
Thank you, I found this thread educational. It also prompted me to check what "caliber" I actually do have, and the answer supprised me even more. I have Armalite 180B and according to them the chambering is 223 hybrid.... What does that mean exactly ?
I'd be asking the seller the same question!
 
I guess I was hoping somebody who knows this stuff to explain me what the "hybrid" chambering means on the 180B.

Jennins: I would rather ask the same question hundred times and look stupid for asking it then not ask a single question that would lead me to do something stupid ... and loose a finger or two ... so when you have something constructive to say, please do share. If you think I have lower IQ then you, great, I have nothing against that, good for you, go on your business and ignore me, let your high intelligence forbid you from wasting you valuable time writing sarcastic posts. my 2cents ... :)

TIA
 
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