Difference between 5.56 and .223 ammo

**voola** · April 26th, 2009, 10:00 PM

B"H

Are the 5.56 and .223 calibre ammos the same? whats the difference? cause all the sites that list 5.56 list it in brackets beside the .223 . Are these 2 calibers virtually the same? can i shoot a 5.56 in a .223 barrel?

**shooter357** · April 26th, 2009, 10:31 PM

Read through this thread.
http://forum.pafoa.org/ammunition-re...mo-223-ar.html

**rwilson452** · April 26th, 2009, 11:20 PM

The short answer is:

Bad idea to shoot 5.56 in a .223 chamber.

Originally Posted by voola

B"H

Are the 5.56 and .223 calibre ammos the same? whats the difference? cause all the sites that list 5.56 list it in brackets beside the .223 . Are these 2 calibers virtually the same? can i shoot a 5.56 in a .223 barrel?

**Fudmottin** · April 28th, 2009, 05:29 PM

The main difference I've noticed is that the military brass is crimped. Extra step for reloading.

I won't argue in favor of doing something that is explicitly discouraged. But I've had no problems firing M193 in a 700VS. My AR uppers are either 5.56 or 300-221.

**Pa. Patriot** · April 28th, 2009, 06:00 PM

Originally Posted by voola

B"H

CUrious, why do you put this at the top of all your posts?

**TXDMERC73** · April 28th, 2009, 06:32 PM

u can shoot a .223 in a 5.56mm barrel but not good idea to shoot a 5.56 mm in a .223 barrel ,but when i had my ruger ranch rifle, i shot both calibers no problems the 5.56 was alot more accurate then the .223.

**Jake Mc.** · May 1st, 2009, 01:38 AM

From Wikipedia

The .223 Remington is a sporting cartridge with almost the same external dimensions as the 5.56x45mm NATO military cartridge. The name is pronounced either two-two-three or two-twenty-three. It is loaded with a 0.224-inch (5.7 mm) diameter, jacketed bullet, with weights ranging from 40 to 90 grains (2.6 to 5.8 g), though the most common loading by far is 55 grains (3.6 g).

While the external case dimensions are very similar, the .223 Remington and 5.56x45mm differ in both maximum pressure and chamber shape. The maximum and mean pressures for some varieties of the 5.56 mm (different cartridge designations have different standards) exceed the SAAMI maximums for the .223 Remington, and the methods for measuring pressures differ between NATO and SAAMI.[2] The 5.56 mm chamber specification has also changed over time since its adoption, as the current military loading (NATO SS-109 or US M855) uses longer, heavier bullets than the original loading did. This has resulted in a lengthening of the throat in the 5.56 mm chamber. Thus, while .223 Remington ammunition can be safely fired in a 5.56 mm chambered gun, firing 5.56 mm ammunition in a .223 Remington chamber may produce pressures in excess of even the 5.56 mm specifications due to the shorter throat.