The 223's are considered more accurate due to differing chamber dimensions and neck diameters.
In an effort to be able to shoot both in a more accurate chamber, the Wylde chamber design was inaugurated. All of my AR15's and '223' bolt guns have either 5.56 Chambers or Wylde Chambers, and I can shoot both types of ammunition in all of them.
The issue with the 223 chamber and the 5.56 case design is that the 5.56 has thicker metal in the necks which are intended for better survival in machine gun applications. In addition to a hotter 5.56 load, this has the potential to create overpressure spikes by restricting neck expansion and bullet release. The military has no interest in reloading, and is interested primarily in preventing feed jams in automatic weapons. Cases fired in such automatic weapons may be stretched to an unsuitable length for reloading because of the generous chamber dimensions intended reduce those feed jams.
Where 308/7.62x51 is involved, that stretching can be even more serious.
Also note that the recent resurgence of the Hornady Frontier Brand has included ammunition labeled as 223 as well as other ammunition labeled as 5.56, and each is specifically loaded to the different cartridge specs. Read those labels.
Much of this is considered by some as conjectural. Regardless; it is still wiser to follow the convention of restricting 223 chambers to 223 headstamped brass.
This is particularly important to handloaders, who may be picking up range brass composed of both sorts of cases. Care must be exercised to cull the 5.56 from cases destined for use in 223 chambers. Also, nearly all factory 5.56 ammunition has crimped primers.
Greg
Topic: Ammo Difference (Read 1409 times)
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