Free Republic

There's already a wealth of information out there, both online and in print, about the differences between .223 Remington and 5.56x45mm NATO. Sadly, a lot of this information is either misguided, ill-founded, or just plain wrong. We’re going to try to set the record straight. These are two cartridges that are really just about as similar as you can get, and are identical from an 5.56 NATO VS. .223 Remington external viewpoint, so the confusion is understandable. Hopefully, though, we can clear up some of the issues surrounding these two cartridges and help you choose between them. This is especially...

Is firing a 5.56 NATO cartridge in your .223 Remington chambered AR15 dangerous? Or do Internet forum-ninjas and ammunition companies selling you commercial ammo instead of surplus overstate the dangers? Believe it or not, a real danger exists, and some gun owners who think they are doing the right thing may not be safe. The Cartridges The .223 Remington and 5.56x45 NATO cartridges are very similar, and externally appear the same. But there are some differences that lie beneath the surface. The 5.56 case has thicker walls to handle higher pressures, meaning the interior volume of the case is smaller...