[Clint N. Suhks]

I’m sure Smith & Wesson M&P15 is a real 5.56mm NATO or else there’d be some big law suits. What does your Stag say it is?

This pretty much proves your theory 5.56 is better than .223 given those specs.

[50cal Smokepole]

The Stag is 5.56. The custom varmint upper is also 5.56. The “leade” mentioned in the article is the key. The fine folks over at Sinclair International stressed that I pay attention to COAL (cartridge overall length). The Barnes Varmint Grenades I use like a little space before the rifling.

[org.whodat]

Lots of foolish stuff posted here, there is no difference in the two rounds military brass is made thicker for shelf life and refurbishing. The two round, military verse civilian, shoot different because of bullet size and bullet crimping. The 223 civilian is more a varmint load. The original ar15’s were chambered in 222 which was a Remington round, rather than buy rights to use the round, the up sized it a hair and changed the neck slope. So a 223 is a fancy 222:, if you get any deformed brass from shooting it will be an over-sized chamber 99% of the time. The military rifle also has a different barrel twist that the civilian, that also will cause a difference in accuracy.