What is the difference between the .223 Remington...?

Question

What is the difference between the .223 Remington cartridge and the 5.56 x 45 mm NATO cartridge? There is a difference can you tell me what it is?

Answer 1

The .223 Remington is the most widely-used centerfire rifle cartridge in the developed world. In its 5.56x45 military form, it is the primary issue ammunition for the U.S. Military and NATO forces. It is a popular sporting cartridge, and probably the most commonly used centerfire varmint cartridge. In our Readers' Poll, the .223 Rem (both standard and improved) ranked first among preferred varmint rounds. The .223 Rem is efficient and versatile. It can sling 40-grainers past 3650 fps, and deliver 90gr VLDs accurately at 1000 yards. Its parent case, the .222 Remington, was once a mainstay of benchrest competition. Today, with custom match bullets, the .223 Remington can still deliver impressive accuracy, shooting well under quarter-MOA in a good rifle.
.223 Remington Cartridge History
The .223 Rem was derived from the .222 Remington, a round popular with benchrest and varmint shooters in the 1950s. The U.S. Army was looking for a new, high-speed small-caliber round to replace the .308 Winchester (7.62x51). To increase velocity with a 55gr bullet, the U.S. Military bumped the .222 Rem's case capacity by pushing forward the shoulder and shortening the neck. This military modification of the .222 Remington was originally called the .222 Special but was later renamed the .223 Remington. In military metric nomenclature, the round is called the 5.56x45. For the full history of the 5.56x45 cartridge, read the 5.56x45 Timeline, by Daniel Watters.

223 Remington vs. 5.56x45--Chambering and Throat Considerations
Is the .223 Remington the same as the 5.56x45? The answer is yes and no. There ARE differences between the .223 Remington as shot in civilian rifles and the 5.56x45 in military use. While the external cartridge dimensions are essentially the same, the .223 Remington is built to SAAMI specs, rated to 50,000 CUP max pressure, and normally has a shorter throat. The 5.56x45 is built to NATO specs, rated to 60,000 CUP max pressure, and has a longer throat, optimized to shoot long bullets. That said, there are various .223 Remington match chambers, including the Wylde chamber, that feature longer throats. Military 5.56x45 brass often, but not always, has thicker internal construction, and slightly less capacity than commercial .223 Rem brass.
Should you be worried about shooting 5.56x45 milspec ammo in a .223 Remington? The answer really depends on your chamber. 5.56 x45 ammo is intended for chambers with longer throats. If you shoot hot 5.56x45 ammo in short-throated SAAMI-spec chambers you can encounter pressure issues. The new long-throated 'Wylde' chamber allows safe use of military ammo. Wylde chambers are quite common in Rock River guns. Other manufacturers, such as Fulton Armory, offer modified "match chambers" with extended throats that allow safe use of 5.56x45 ammo in .223 Remington rifles. For a complete discussion of the .223 Rem vs. 5.56x45 question, read this Tech Notice from Winchester, and this GunZone Commentary by Dean Speir. Without belaboring the point, we'll repeat the official SAAMI position: "Chambers for military rifles have a different throat configuration than chambers for sporting firearms which, together with the full metal jacket of the military projectile, may account for the higher pressures which result when military ammunition is fired in a sporting chamber. SAAMI recommends that a firearm be fired only with the cartridge for which it is specifically chambered by the manufacturer."

http://www.6mmbr.com/223Rem.html





D58


Hunting with Rifle, Pistol, Muzzle loader and Bow for over 3 decades.
Reloading Rifle, Pistol and shotgun for over 3 decades.

Answer 2

Difference Between 223 And 5.56

Answer 3

OK here goes.
The cartridge casings for both of these cartridge cases are basically the same as far as the length and exterior dimentions are concerned. The 5.56 loaded to military specs usually have thicker case walls, and a thicker "head" for extra strength. (This heavier weight handles increased pressures easier) On the down side, the heavier case reduces powder capacity.
The 5.56 and .223 Remington chambers are nearly indentical. The difference is in the "Leade" dimentions. Leade is the barrel area directly in front of the firearm chamber where the rifling stops in order for the bullet to "seat" properly. "Leade" in a .223 caliber chamber is .085, in the 5.56mm chamber the leade is .162, almost twice as much as the .223 Remington chamber..
You can fire .223 Remington cartridges in a 5.56mm gun chamber with the longer "leade", but you will lose a bit of accuracy and velocity over firing the.223 Remington in the chamber with the shorter leade it was desined for.
You can also experience problems shooting higher pressure military 5.56mm cartridges in a .223 Remington rifle with it's much shorter leade.
Chamber pressures are greater in firearms with the shorter leade too. This can result in blown cartridge case heads,primer pocket gas leaks and expansion issues, and over-all function of the firearm.
Most 5.56mm ammunition is full metal jacketed.Performance bullets,hollow points,soft points, ballistic bullets etc are loaded into .223 Remington cartridge cases. Again...Firing a .223 Remington cartridge in a 5.56mm is PERFECTLY SAFE, and will only slightly effect recoil and accuracy..
It is NOT reccomended that you shoot 5.56X45 NATO Military ammunition in a firearm chambered for .223 Remington. The shorter "leade" can result in pressure related problems I already mentioned
Whew...............The differences spelled out....

Answer 4

You've already got good answers to this--Logan..., JD, and D58. The basic rule I have always been told is you can safely fire .223 into any firearm chambered in 5.56, but unless specified (like the Mini-14) 5.56 should not be fired in a .223.

Answer 5

There ARE differences between the .223 Remington as shot in civilian rifles and the 5.56x45 in military use. While the external cartridge dimensions are essentially the same, the .223 Remington is built to SAAMI specs, rated to 50,000 CUP max pressure, and normally has a shorter throat. The 5.56x45 is built to NATO specs, rated to 60,000 CUP max pressure, and has a longer throat, optimized to shoot long bullets. That said, there are various .223 Remington match chambers, including the Wylde chamber, that feature longer throats. Military 5.56x45 brass often, but not always, has thicker internal construction, and slightly less capacity than commercial .223 Rem brass.

Should you be worried about shooting 5.56x45 milspec ammo in a .223 Remington? The answer really depends on your chamber. 5.56 x45 ammo is intended for chambers with longer throats. If you shoot hot 5.56x45 ammo in short-throated SAAMI-spec chambers you can encounter pressure issues. The new long-throated 'Wylde' chamber allows safe use of military ammo

Answer 6

I believe that the 5.56 round produces more pressure than the .223. using a 5.56 round in a .223 designed rifle can be unsafe.
those chambered for the 5.56 can accept the .223 rem

Answer 7

Good question you had 8 years ago I often wondered myself.

Answer 8

the 5.56x45 is the same as the .223. 5.56x45 is what the military calls it, .223 is what it is called to sell to civilians. There is no difference at all although velocity and such can differ by manufacturer as is the same with any type of ammunition, some military ammo is AP. Both are the same but with different names.

Answer 9

cartridge length yet same diameter bullet

Answer 10

5.56x45