5.56x45mm vs .223 Remington - Page 3

BAC · June 28th, 2009, 12:53 PM

Matt, methinks your sig line is oddly appropriate here.

-B

BAC · June 28th, 2009, 01:02 PM

Quote:

Originally Posted by Sig 210

There are several myths concerning military 5.56mm ammo. It is a myth that US made 5.56mm cases are thicker than commercial cases. For over 40 years I have weighed my cases when real good accuracy is desired. See the link below for case weights.

It is also a myth that 5.56mm military ammo is loaded to much higher pressure than commercial .223 ammo. US military 5.56mm ammo is loaded to 52,000 Psi + 3 standard deviations; not to exceed 58,000 psi. SAAMI specs are 55,000 psi.

SAAMI pressures

BTW: There are at least a dozen different .223 chambers. Unless your rifle is an H@R Handi rifle or it has a tight .223 match chamber there are no problems with firing 5.56mm military ammo in that gun. H@R re-ground their reamers and their chambers are all over the place from huge to very tight.

A gunsmith friend says that he knows of no US firearm maker who currently uses a SAAMI chamber for the .223.

This is a good link to peruse:

AR15BARRELS.COM - Technical Documents

That's interesting. The two relevant PDFs on that website both indicate a noteworthy variance between .223 Rem and 5.56x45, and even more curiously the second PDF describes a lack of consistency in .223 Rem chamberings compared to in 5.56x45 chamberings. NATO EPVAT testing indicates that 5.56 NATO chambers must be proofed to 62,000 psi. Max pressures for a rifle/ammo combo are to add 25% to the stated pressure, totaling almost 80,000 psi (yes, that's significantly higher than the lower SAAMI pressures).

I'll give you that some military ammo is loaded on the higher end of the allowed SAAMI specs, but there's a lot more room for pressure spikes (military concern given the sheer volume of ammo they receive) and reloading errors in NATO chambers than in SAAMI chambers. I'd sooner take the low end of the NATO chamber than the high end of the SAAMI chamber.

-B

Tubby45 · June 28th, 2009, 01:51 PM

Quote:

Originally Posted by Sig 210

There are several myths concerning military 5.56mm ammo. It is a myth that US made 5.56mm cases are thicker than commercial cases. For over 40 years I have weighed my cases when real good accuracy is desired. See the link below for case weights.

Then explain to me why military brass has less case capacity and is heavier.

Quote:

A gunsmith friend says that he knows of no US firearm maker who currently uses a SAAMI chamber for the .223.

Gee, probably all the SAAMI members who must abide by the SAAMI specs for every firearm chamber they cut.

Sig 210 · June 28th, 2009, 02:30 PM

Quote:

Then explain to me why military brass has less case capacity and is heavier.

US military 5.56mm brass does not have less capacity and it is not heavier. I have weighed .223 and 5.56mm cases for years. The heaviest cases made are Lapua match. Some Brit 5.56mm cases are very heavy.

Go to the link: Click on Tech and then click on brass weights.

AR15BARRELS.COM - Technical Documents

Quote:

Gee, probably all the SAAMI members who must abide by the SAAMI specs for every firearm chamber they cut.

Not so. For about 25 years Ruger has said that their rifles rifles will accept either 5.56mm or .223 ammo.

Sig 210 · June 28th, 2009, 02:35 PM

Quote:

NATO EPVAT testing indicates that 5.56 NATO chambers must be proofed to 62,000 psi.

How does the proofing of a barrel translate into cartridge working pressure?

BAC · June 28th, 2009, 02:42 PM

Did you read the last part of my statement?

-B

Sig 210 · June 28th, 2009, 03:04 PM

I am not advocating that anyone fire any 5.56mm ammo in a .223 SAAMI chamber.

I am saying that annually for the past 41 years I have fired somewhere between 10,000-30,000 rounds of 5.56mm military ammo in .223 and 5.56mm chambers with no ill effect.

Yes, I do own pressure testing equipment and one of my .223 guns is set up with it as we speak.

Tubby45 · June 28th, 2009, 05:26 PM

Quote:

Originally Posted by Sig 210

US military 5.56mm brass does not have less capacity and it is not heavier. I have weighed .223 and 5.56mm cases for years. The heaviest cases made are Lapua match. Some Brit 5.56mm cases are very heavy.

Go to the link: Click on Tech and then click on brass weights.

AR15BARRELS.COM - Technical Documents

Right, and Randall only weighed a few cases and came up with a theory. We load about 30,000 rounds a week of .223 using fired military brass and commercial brass. The commercial brass is lighter and holds more than the military brass. This is consistent across the little over 3 million rounds of .223 my company has loaded over the last two years.

Quote:

Not so. For about 25 years Ruger has said that their rifles rifles will accept either 5.56mm or .223 ammo.

Newsflash: you can chamber a 5.56 NATO round in a .223 SAAMI chamber. That's nothing new and proves nothing.

BamaSteve · June 28th, 2009, 06:22 PM

Good info for me in the future. I plan on getting some sort of rifle and I suppose I'll look at the 5.56 chambered weapons, due to the versatility it provides.

I think this a long time out for me though :(

Eagleks · June 28th, 2009, 11:57 PM

Geeez... I was just trying to keep it simple... not give a whole detailed thesis on the differences......

the real point is simple.... if it's a 5.56 / .223 barrel you can shot both ammos in it, if it's purely .223 you can only shoot .223 in it (gee ... just like a .357 & .38 ..they aren't dimensionally the same either).

So, buy the one that shoots both and quit worrying about it.

June 28th, 2009, 12:53 PM	#21
BAC Distinguished Member Join Date: May 2007 Location: Tampa, Florida Posts: 1,980	Matt, methinks your sig line is oddly appropriate here. -B __________________ RIP, Jeff Dorr: 1964 - July 17, 2009. You will be missed. Defensive Carry Search Tips Step 1 - Choose a subforum on right side under "Search in Forum(s)" Step 2 - Type general topic of interest in "Search by Keyword" textbox. Step 3 - Read results and refine/repeat as necessary.

June 28th, 2009, 02:42 PM	#26
BAC Distinguished Member Join Date: May 2007 Location: Tampa, Florida Posts: 1,980	Did you read the last part of my statement? -B __________________ RIP, Jeff Dorr: 1964 - July 17, 2009. You will be missed. Defensive Carry Search Tips Step 1 - Choose a subforum on right side under "Search in Forum(s)" Step 2 - Type general topic of interest in "Search by Keyword" textbox. Step 3 - Read results and refine/repeat as necessary.

June 28th, 2009, 06:22 PM	#29
BamaSteve Senior Member Join Date: Dec 2008 Location: Alabama Posts: 663	Good info for me in the future. I plan on getting some sort of rifle and I suppose I'll look at the 5.56 chambered weapons, due to the versatility it provides. I think this a long time out for me though :( __________________ Smith & Wesson M&P9cCrossbreed Supertuck EDC Light:Nitecore EX10 R2 EDC Knife:Remington Sportsman Series “If a nation expects to be ignorant and free, in a state of civilization, it expects what never was and never will be.” --Thomas Jefferson 1816

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June 28th, 2009, 03:04 PM	#27
Sig 210 Senior Member Join Date: Oct 2006 Location: Southwestern OK Posts: 797	I am not advocating that anyone fire any 5.56mm ammo in a .223 SAAMI chamber. I am saying that annually for the past 41 years I have fired somewhere between 10,000-30,000 rounds of 5.56mm military ammo in .223 and 5.56mm chambers with no ill effect. Yes, I do own pressure testing equipment and one of my .223 guns is set up with it as we speak.

June 28th, 2009, 11:57 PM	#30
Eagleks Distinguished Member Join Date: May 2008 Location: Kansas Posts: 1,686	Geeez... I was just trying to keep it simple... not give a whole detailed thesis on the differences...... the real point is simple.... if it's a 5.56 / .223 barrel you can shot both ammos in it, if it's purely .223 you can only shoot .223 in it (gee ... just like a .357 & .38 ..they aren't dimensionally the same either). So, buy the one that shoots both and quit worrying about it.