Off topic

[Russ Pagels]

My friend bought a stag arms AR-15. the receiver is marked 5.56X45,my DPMS is marked 5.56MM and .223.I thought I read some where,the rifleman?, that the two rounds were not interchangeable and could lead to problems. any one know. Bruce are you there?...Thanks Russ

[Face]

"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.[6]"

From: http://en.wikipedia.org/wiki/.223_Remington

[Face]

Using commercial .223 Remington cartridges in a 5.56 mm NATO chambered rifle should work reliably, but generally will not be as accurate as when fired from a .223 Remington chambered gun due to the longer leade.[15] Using 5.56 mm NATO mil-spec cartridges (such as the M855) in a .223 Remington chambered rifle can lead to excessive wear and stress on the rifle and even be unsafe, and the SAAMI recommends against the practice.[16][17] Some commercial rifles marked as ".223 Remington" are in fact suited for 5.56 mm NATO, such as many commercial AR-15 variants and the Ruger Mini-14(marked ".223 cal"), but the manufacturer should always be consulted to verify that this is acceptable before attempting it, and signs of excessive pressure (such as flattening or gas staining of the primers) should be looked for in the initial testing with 5.56 mm NATO ammunition.[


http://en.wikipedia.org/wiki/5.56x45mm_NATO