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Posted: 12/17/2004 9:25:26 AM EDT
| Please pardon my ignorance, but I need to clear something up. I was always under the impression that these rounds were identical, just named different due to civilian/military reasons (much like the .308/7.62. Can either round be fired from any AR15? I ask because I read somewhere recently that you couldn't fire 5.56 ammo from an AR chambered for .223, but you could fire either round from a weapon chambered for the 5.56. Is this just internet noise or what? |
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Unfortunately, that website is blocked here at work. I guess they haven't gotten around to blocking this site and 1911forum, or I'd be totally screwed. So, a rifle chambered for 5.56 is built beefier than a .223 chamber? I'd like to be able to take advantage of good deals on surplus ammo when I finally get to purchase my first AR. Or is there that much difference in price? |
Here's some of the information from the Ammo Oracle:
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Not beefier, just a tad more expansion room in the shoulder and neck, and a little more unrifled area in the bore just ahead of the chamber, called the leade or throat. Both intended to keep pressures from exceeding limits, especially the throat. If the bullet is already engaging the rifling while in the chamber, the chances are that pressures will spike when the round is fired. The extreme is the 80 grain match round; the bullet is so long that specially-chambered rifles should be used which need even more leade than a standard .223 chambering to fire that round without going KBoom. 5.56 and .223 chambers can be made from the same lot of barrel blanks, only difference is in how the chamber and barrel rifling are cut. |
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