BULLETS AND BARREL TWIST
(From Four Guys Guns) The .223 and the 5.56×45 cartridge are some of the most commonly used rifle cartridges in the U.S. and the world today. There are many similarities between the two but bear in mind you should REALLY know the differences. I could write a really long and possibly dry article on all the intricacies, uses, history and dimensions, but this is not for re-loaders, competition shooters or experienced people. You want the straight deal on what this means for you and your new rifle, and we can expand on knowledge from there.