.223 remington versus 5.56 x 45 mm NATO - is it safe to interchange???
- Thread starter Boltgun
- Start date
- Location
- West Quebec
Re .223 vs. 5.56 : My understanding (and may be a little too simple) is that 5.56 NATO ammo is loaded to higher pressures and with a shorter leade (jump from throat to rifling starting point) - bore is the same. This will cause spikes in chamber pressures that will over time cause failure somewhere in the action. Get a gunsmith to run a chambering reamer in your .223 chamber to covert the leade and then watch for signs of over-pressure.
re 7.62 NATO ammo in civilian .308 rifles : Military arms are designed to function under horrible conditions and still chamber ammo even if it's dirty, or there's dirt in the chamber, hence the longer/wider chamber size. Because the chambering is sloppy (certainly by reloader's standards) the brass will expand to fill the chamber and probably never easily shrink back to the proper dimensions even when re-sized. The ammo is compatible, but not necessarily re-useable! New military brass in .308 rifles should last a long time because it's thicker/stronger. Thoughts?
re 7.62 NATO ammo in civilian .308 rifles : Military arms are designed to function under horrible conditions and still chamber ammo even if it's dirty, or there's dirt in the chamber, hence the longer/wider chamber size. Because the chambering is sloppy (certainly by reloader's standards) the brass will expand to fill the chamber and probably never easily shrink back to the proper dimensions even when re-sized. The ammo is compatible, but not necessarily re-useable! New military brass in .308 rifles should last a long time because it's thicker/stronger. Thoughts?
I have done some major testing in regards to NATO spec ammunition vs standard civilian ammunition. Indeed there are significant pressure differences between the ammunition types. However, most rifles are now interchangeable between NATO vs non-NATO ammo. I've seen the Ruger Mini-14 rated for .223 only use 5.56 NATO and after a few rounds and the action seized - now this was the target shooting addition version of the Mini-14 mind you. So yes, you do have to be careful. Read carefully.
Another minor difference between mil-spec 5.56 and civilian .223 that may have been overlooked is that the primers are crimped into their pockets on mil-spec brass. The primers are crimped in so that they do not back out of the base of the case during recoil, especially under military conditions like sustained fire where cartridges are subjected to multiple recoil vibrations when stored in a large capacity magazine, ammo cans or belts.
When re-loading mil-spec brass you have to take the time to hand ream each primer pocket to get a fresh primer to seat.
I have never had a problem with civilian factory-new ammo ever having a primer back out on it's own during casual target shooting, but I guess it could potentially happen and cause a failure if used in a military environment which is why mil-spec case primers are crimped in.
Occasionally one of my mil-spec reloaded cases would have a primer back out on it's own just from being stored for a long period of time, and I also have had the occasional re-load primer back out from jiggling in the magazine, which could be a result of taking away a tiny bit too much material from the base when reaming.
I have not reloaded for 308/7.62, but I would expect that the primers are crimped in on military brass of that caliber also.
When re-loading mil-spec brass you have to take the time to hand ream each primer pocket to get a fresh primer to seat.
I have never had a problem with civilian factory-new ammo ever having a primer back out on it's own during casual target shooting, but I guess it could potentially happen and cause a failure if used in a military environment which is why mil-spec case primers are crimped in.
Occasionally one of my mil-spec reloaded cases would have a primer back out on it's own just from being stored for a long period of time, and I also have had the occasional re-load primer back out from jiggling in the magazine, which could be a result of taking away a tiny bit too much material from the base when reaming.
I have not reloaded for 308/7.62, but I would expect that the primers are crimped in on military brass of that caliber also.
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This can only happen if the pocket is dangerously loose. The usual cause is over-pressure loads, singly or repeatedly. I suppose if you reamed the heck out of a pocket, with a cutting-type reamer, the same thing could happen.
Don't ream primer pockets use a pocket swager. They are not expensive and a useful tool.
This is true.
Depends on the "brand' of military brass also. If when reaming the pocket such that removing the minimal amount of material necessary to fit in a new primer is actually too much reaming to hold the new primer in, these types of cases are actually not reloadable and should be discarded. Unfortunately it is hard to tell, since it feels like a proper tight fit when loading the primer with the press.
I load 5.56 with 19.8 grains of IMR 4198 and a 55 gr FMJ BT, should be safe...
I have used both hand reamers, and also electric drills, but it's a hassle.
It is. Here are all of the alternatives: http://squibloads.wordpress.com/reloading/get-the-crimp-out/
- Location
- Georgetown Ontario
SAAMI states it as unsafe to shoot 5.56 Nato ammo in a commercial spec .223 chambered gun! That's proof enough for me.
Rooster1a2
Regular
- Location
- North Vancouver, BC
Incidentally, isn't the pressure limit for CIP .223 the same/similar to 5.56 NATO?
Also, regarding earlier statements in the thread about XCR barrels being marked .223 instead of 5.56 NATO in order to allow export - I have one marked 5.56 NATO. So in my mind there are two possibilities: 1) The regulations which caused manufacturers to use the .223 mark instead of 5.56 NATO have expired/been retracted or 2) those barrels actually had .223 chambers.
I have to say - it seems dishonest, for lack of a better term, to mark a barrel with a 5.56 NATO chamber as .223. The same applies to ammunition marked .223/5.56. This is a huge pet peeve of mine.
http://www.luckygunner.com/labs/5-56-vs-223/
Folks,
check out this link, these guys actually have scientific proof that .223 and 5.56 are OKAY to use together, rather that a bunch of nonsence formed opinions!
As I have seen this show up regularly, and people on both sides of the coin continue to argue it, I am making this a sticky for those who want to refer to the governing body of the ammunition industry. That is the Sporting Arms and Ammunition Manufacturing Institute also referred to as SAAMI.
Here is a comparion of the .223 Remington versus 5.56 x 45mm NATO chambers:
Further to that, this is a link to the unsafe arms and ammunition combination pages:
http://www.saami.org/specifications...1-Unsafe_Arms_and_Ammunition_Combinations.pdf
I hope this helps those that are not sure.
Boltgun
Nothing new about this discussion .... from the "Questions & Answers" column of the 'The American Rifleman' magazine, Dec. 1975
"Springfield .30-'06 Barrels - Bullets of military issue ball rounds have to move forward about 1/8" before contacting the throat in my M1903A3 Springfield rlfle. Is this normal in an 'as new' rifle?"
"The condition you describe is normal. For years the Springfield barrels were dimensioned so that the bullet of a chambered cartridge cleared the forcing cone (commonly called the throat) by about 1/32" to 1/16" prior to firing.
WW II production showed that it was difficult to maintain such close tolerances in arms and ammunition. Some bullets were sufficiently large to engage the forcing cone as they were chambered. This could result in the case separating from the bullet, the powder spilling in the chamber. Removing the bullet required a cleaning rod. This was remedied by reaming the forcing cone to advance it about 1/10th" in new barrels and barrels on hand.
A similar situation was experienced with .50 caliber MG barrels. The forcing cone was advanced about 1/2 caliber (1/4") by reaming new barrels and barrels on hand. According to Ordnance Field Service Modification Work |Order, a long burst was to be fired to advance the forcing cone the required amount by erosion if a forcing cone reamer was not available."
There is a not-to-scale drawing of the description.
This is how military .30-'06 chambers got known as being overly large by civilian standards. The story is similar for .303 Lee-Enfield barrels, only we were told it was to chamber dirty, bent ammunition.
"Springfield .30-'06 Barrels - Bullets of military issue ball rounds have to move forward about 1/8" before contacting the throat in my M1903A3 Springfield rlfle. Is this normal in an 'as new' rifle?"
"The condition you describe is normal. For years the Springfield barrels were dimensioned so that the bullet of a chambered cartridge cleared the forcing cone (commonly called the throat) by about 1/32" to 1/16" prior to firing.
WW II production showed that it was difficult to maintain such close tolerances in arms and ammunition. Some bullets were sufficiently large to engage the forcing cone as they were chambered. This could result in the case separating from the bullet, the powder spilling in the chamber. Removing the bullet required a cleaning rod. This was remedied by reaming the forcing cone to advance it about 1/10th" in new barrels and barrels on hand.
A similar situation was experienced with .50 caliber MG barrels. The forcing cone was advanced about 1/2 caliber (1/4") by reaming new barrels and barrels on hand. According to Ordnance Field Service Modification Work |Order, a long burst was to be fired to advance the forcing cone the required amount by erosion if a forcing cone reamer was not available."
There is a not-to-scale drawing of the description.
This is how military .30-'06 chambers got known as being overly large by civilian standards. The story is similar for .303 Lee-Enfield barrels, only we were told it was to chamber dirty, bent ammunition.
Yep. Your right. A whole 2400psi higher. Talking in the 35000 psi area here.
Look I honestly have shot 9mm NATO in 9mm para pistols and 5.56 NATO in 223rem rifles for the last 30 years. I have all my teeth, fingers, eyeballs. Nothing has exploded on me.
Moe
