5.56 nato

PA Chuck Hunter · June 18, 2010, 12:39 PM

I am a beginner who is curious about the difference in casings between the 5.56 NATO and .223 Remington

There is an opportunity to buy some once fired resized & reprimed 5.56 NATO brass and I would like to reload in accordance with the Sierra handbook suggestion for .223 Remington: 55 grain FMJBT bullet using 25 grains H335 powder (~2900 fps). Would I be OK with this?

Mtn Biker · June 18, 2010, 01:21 PM

The latest info I have seen shows NATO 5.56 cases have similar volume to commercial cases. (It used to be thought they had less volume due to thicker brass) You should be just fine with that load but..... I would load a handful at a reduced load just as a precaution and try them in your gun. That way you would be sure there are no signs of high pressure and that the cases feed and eject ok in your gun. If they look ok then work up to 25gr and you should be good to go.
It would be the pits to find out that the brass is not sized correctly after you have a couple hundred rounds loaded!

VL

Edward429451 · June 18, 2010, 01:26 PM

All you have to do is to weigh a bunch of cases 233/5.56 and you see that they weigh about the same, sometimes the 223 cases are the heavy ones!

size and trim before you weigh

**Unclenick** · June 18, 2010, 02:43 PM

The cases are not different, when new, just the chambers are. The NATO chambers are bigger. This is to allow easier feeding and extraction when firing full auto. As a result, cases fired in NATO chambers are usually bigger than those fired in .223 chambers, and have to be sized down more to fit a SAAMI chamber. Some NATO guns, particularly machine guns, can actually stretch them beyond the point a standard die can bring them back small enough to chamber in some SAAMI chambers. Most of commercial reconditioners roll size them for that reason. Once fired in your chamber, they should be OK. Only once in awhile do you get cases that can't be made to fire in a commercial chamber, and you just have to toss those.

NATO 7.62×51 cases are usually heavier than commercial .308 Win cases. I have not run into that with 5.56×45 vs. .223 Rem cases, but you should doublecheck each headstamp. Figure a weight difference of about 4 grains is call to knock your charge down 0.2 grans if the case is 4 grains heavier, and to raise it 0.2 grains if it is 4 grains lighter. That will keep your rounds running pretty even.

H335 is a little slower than I like to use with anything under 60 grains. You have to keep its pressure up for uniform burning with lighter bullets. I prefer Reloader 10X for 55 grain bullets and IMR 4198 for anything lighter.

amamnn · June 18, 2010, 06:05 PM

Apparently there is or was a sudden increase in retired military ammo. Some of the shooters I meet at the old soldiers service rifle matches here have shown up with bandoliers of .556x45 NATO over the last couple of months. These folks buy bulk US made ammo and shoot it in chambers made as described by Nick. They then have cases to reload for quite some time.

Those people wishing to do the same should ensure that their rifles are chambered for the .556 and that the cartridges are boxer primed. Not all NATO countries use the boxer (easily reloaded) primer in their cases.

medalguy · June 19, 2010, 11:14 PM

Personally, I prefer to buy once fired brass unsized and uncleaned. That way I can see exactly what the brass looks like and from that I can tell if it's been reloaded previously. I can also then be assured that it's resized properly (since I'm doing it) and the primers are correct and properly installed. It may take a little less time if you buy prepared brass, but you can never be sure exactly what you're getting either.

steve4102 · June 20, 2010, 01:58 PM

My only comment is on your 25gr of 335. According to Sierra 25.7gr is max and according to Hodgdon 25.3gr is max. If you are planning to start with 25gr I think you are starting out to high. Drop your charge down to the "Start" charge and work up looking for accuracy and signs of pressure. As your Sierra manual says, "always start low and work up".

June 18, 2010, 12:39 PM	#1
PA Chuck Hunter Junior Member Join Date: May 13, 2010 Posts: 6	5.56 nato I am a beginner who is curious about the difference in casings between the 5.56 NATO and .223 Remington There is an opportunity to buy some once fired resized & reprimed 5.56 NATO brass and I would like to reload in accordance with the Sierra handbook suggestion for .223 Remington: 55 grain FMJBT bullet using 25 grains H335 powder (~2900 fps). Would I be OK with this?

June 18, 2010, 02:43 PM	#4
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,742	The cases are not different, when new, just the chambers are. The NATO chambers are bigger. This is to allow easier feeding and extraction when firing full auto. As a result, cases fired in NATO chambers are usually bigger than those fired in .223 chambers, and have to be sized down more to fit a SAAMI chamber. Some NATO guns, particularly machine guns, can actually stretch them beyond the point a standard die can bring them back small enough to chamber in some SAAMI chambers. Most of commercial reconditioners roll size them for that reason. Once fired in your chamber, they should be OK. Only once in awhile do you get cases that can't be made to fire in a commercial chamber, and you just have to toss those. NATO 7.62×51 cases are usually heavier than commercial .308 Win cases. I have not run into that with 5.56×45 vs. .223 Rem cases, but you should doublecheck each headstamp. Figure a weight difference of about 4 grains is call to knock your charge down 0.2 grans if the case is 4 grains heavier, and to raise it 0.2 grains if it is 4 grains lighter. That will keep your rounds running pretty even. H335 is a little slower than I like to use with anything under 60 grains. You have to keep its pressure up for uniform burning with lighter bullets. I prefer Reloader 10X for 55 grain bullets and IMR 4198 for anything lighter. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

June 18, 2010, 01:21 PM	#2
Mtn Biker Senior Member Join Date: January 12, 2009 Posts: 122	The latest info I have seen shows NATO 5.56 cases have similar volume to commercial cases. (It used to be thought they had less volume due to thicker brass) You should be just fine with that load but..... I would load a handful at a reduced load just as a precaution and try them in your gun. That way you would be sure there are no signs of high pressure and that the cases feed and eject ok in your gun. If they look ok then work up to 25gr and you should be good to go. It would be the pits to find out that the brass is not sized correctly after you have a couple hundred rounds loaded! VL

June 18, 2010, 01:26 PM	#3
Edward429451 Junior member Join Date: November 12, 2000 Location: Colorado Springs, Colorado Posts: 9,494	All you have to do is to weigh a bunch of cases 233/5.56 and you see that they weigh about the same, sometimes the 223 cases are the heavy ones! size and trim before you weigh

June 18, 2010, 06:05 PM	#5
amamnn Senior Member Join Date: May 13, 2006 Location: WA, the left armpit of the USA Posts: 1,323	Apparently there is or was a sudden increase in retired military ammo. Some of the shooters I meet at the old soldiers service rifle matches here have shown up with bandoliers of .556x45 NATO over the last couple of months. These folks buy bulk US made ammo and shoot it in chambers made as described by Nick. They then have cases to reload for quite some time. Those people wishing to do the same should ensure that their rifles are chambered for the .556 and that the cartridges are boxer primed. Not all NATO countries use the boxer (easily reloaded) primer in their cases.

June 19, 2010, 11:14 PM	#6
medalguy Senior Member Join Date: August 31, 2009 Location: New Mexico Posts: 1,033	Personally, I prefer to buy once fired brass unsized and uncleaned. That way I can see exactly what the brass looks like and from that I can tell if it's been reloaded previously. I can also then be assured that it's resized properly (since I'm doing it) and the primers are correct and properly installed. It may take a little less time if you buy prepared brass, but you can never be sure exactly what you're getting either.

June 20, 2010, 01:58 PM	#7
steve4102 Senior Member Join Date: December 23, 2005 Location: Minnesota Posts: 2,968	My only comment is on your 25gr of 335. According to Sierra 25.7gr is max and according to Hodgdon 25.3gr is max. If you are planning to start with 25gr I think you are starting out to high. Drop your charge down to the "Start" charge and work up looking for accuracy and signs of pressure. As your Sierra manual says, "always start low and work up".