.223/5.56

mag627

mag627

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Hi
I know that if a barrel is marked .223 then you don't use 5.56 in it.
but
I would like to know what the difference would be in performance between milspec 5.56 and (for example) pmc 55 fmj.

I know there is a pressure difference but would like to know fps and energy differences for comparable ammo.
thanks
 
.223 and 5.56 are the same. If there was a promblem shooting 5.56 in .223 rifles or vice versa there would be pictures all over the internet of blown up rifles warning of such dangers.
When the DCRA still issued ammo for annual competition many people built .223 rifles to shoot 5.56 IVI.
 
There ARE warnings all over the internet against using 5.56mm ammo in .223 rifles.

But, according to Canada Ammo, the PMC 55gr fmj is 5.56mm M193 specification. It is not .223 SAAMI ammunition.
 
The difference is in chamber throat. When Savage was working on the idea of a 1:9 223 barrel, the throat issue was addressed. Instead of a SAAMI throat, they put in a deeper one, so it could digest all flavours of 5.56.

If you know a gunsmith, it is easy to put a throating reamer on a T handle and touch a 223 throat, if it needs it. I have done a few dozen by hand when working on Savage prototypes, before they found the solution.

I know Savage rifles in 1:9 are made to take 5.56. Some other big makers have probably done the same thing.

If you don't reload yourself, ask a relaoder to measure your rifle's throat length. If a bullet has to be seated a long way out to touch the rifleing, it is ok with 5.56.

Pressures are the same.
 
Read this,hope it helps




P.O. Box 299 Geneseo IL 61254 Tel 309-944-6939 fax 309-944-6949 info@armalite.com
December 4, 2002
TECHNICAL NOTE 45: 5.56 NATO vs SAAMI .223 Remington Chambers
BACKGROUND: We are often asked whether our rifles feature NATO (North Atlantic Treaty Organization)
or SAAMI (Small Arms and Ammunition Manufacturers Institute) standard 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 case mouth, and the “lead” or
“leade,” the 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 features less freebore and a tighter leade, which normally provide better bullet fit and
match-grade 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 15 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 or powder stains that reveal gasses leaking around the
primer.


The first few rounds of ALL ammunition, from whatever source or lot, should be checked for pressure and
other signs of 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 special, modified SAAMI chambers 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.
ArmaLite’s larger AR-10 rifles are all chambered with 7.62mm NATO chambers. .308 Winchester (SAAMI
standard) ammunition functions perfectly in the 7.62mm chambers.
© 2001 ArmaLite, Inc."
 
And hear I am..............:D

'Maynard' hit the nail on the head, I wept openly last week there was a guy on the 'EE' selling all his 556 cuz his rifle was chambered for 223

I have mixed and matched for decades out of a myriad of rifles (bolt-semi) marked 223/556 762/308 with nary a hiccup.....
 
Last edited:
Thanks for the feedback

More specific question
what are the fps/energy of a military spec'd round vs an off the canadian tire shelf fps/energy (say at 100 yds)
 
Presures and velocity of 5.56 and 223 are similar.

5.56 is made to have a specified range of port pressures at the gas port. not too much - not too little. The 5.56 pressure barrel maeasures pressure at the chamber and at the gas port.

I have never tested 223 in a 5.56 test barrel, but I would expect the majority to work just fine. But there would be no guarantee of that.

223 ammo can be shot if 5.56 barrels. Years ago 5.56 ammo was not good in some 223 barrels (chambers). I would be surprised if any 223 rifles made now by major manufacturers (companies with lawyers) are incompatible with 5.56 ammo, but I would measure the throat before trying it.
 
jennis said:
And hear I am..............:D

'Maynard' hit the nail on the head, I wept openly last week there was a guy on the 'EE' selling all his 556 cuz his rifle was chambered for 223

I have mixed and matched for decades out of a myriad of rifles (bolt-semi) marked 223/556 762/308 with nary a hiccup.....
Click to expand...

was I the guy selling it?:redface: oes 630 rounds of 5.56 sound about right.
I might not of sold it if I had new better but I did get what I payed for my ammo back and now I can get some better match grade stuff.

I still have some 5.56 tracer though.;) so you guys are saying it would be fine to shoot the tracers out of my rem 700 sps 223 tactical?
 
ammo.ar15.com/project/AmmoOracle_061808.pdf

Follow the link above and pour yourself a drink. 53 pages of info on .556/.223
:)
 
Greenhorse six said:
Read this,hope it helps




P.O. Box 299 Geneseo IL 61254 Tel 309-944-6939 fax 309-944-6949 info@armalite.com
December 4, 2002
TECHNICAL NOTE 45: 5.56 NATO vs SAAMI .223 Remington Chambers
BACKGROUND: We are often asked whether our rifles feature NATO (North Atlantic Treaty Organization)
or SAAMI (Small Arms and Ammunition Manufacturers Institute) standard 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 case mouth, and the “lead” or
“leade,” the 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 features less freebore and a tighter leade, which normally provide better bullet fit and
match-grade 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 15 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 or powder stains that reveal gasses leaking around the
primer.


The first few rounds of ALL ammunition, from whatever source or lot, should be checked for pressure and
other signs of 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 special, modified SAAMI chambers 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.
ArmaLite’s larger AR-10 rifles are all chambered with 7.62mm NATO chambers. .308 Winchester (SAAMI
standard) ammunition functions perfectly in the 7.62mm chambers.
© 2001 ArmaLite, Inc."
Click to expand...

Thanks for the solid information
 
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