from Gun Digest..

 

the first couple of pages of this is the history of 223 vs 556 pressures.. the last part is pretty good discussion about whether you are really 556 or not..

 

http://www.gundigest.com/223-vs-5-56

Ill check this link on my pc

Now I have to buy a throat checker and maybe a reamer. BTW I have suspected this many times.

Excellent article.

*sigh* go look at the reamer dimensions. There are 5.56 reamers new out of the box that are tighter than some .223 reamers out of the box. Then you have things like .223 wylde and 5.56 sam-r which are tighter than 5.56 that are designed and intended to shoot 5.56. If you aren't popping primers, worst case is you are probably just wearing out your bolt and barrel a bit faster. Their solution to this is to buy a device to ream out the leade right through the chrome. Their answer to why you shouldn't care is that you are flame cutting it anyway.

 

Also, signs that this article may just be written by someone who's measure of reality may not be all that relevant. 1) they start it with a filler page of irrelevant history. 2) The guy says don't believe round counts, and tells you a claim of 1000 rounds in a weekend is a lie or will destroy the barrel. FYI, lets say you do a two day class, 8 hours of range time a day. You'd average one shot ever 57.6 seconds to hit 100 rounds? That's one 30 round mag every 28 minutes.

At this point, many an advocate of “there is no difference” will say “I’ve shot thousands of rounds through my AR and it hasn’t given me any problems.” I’ve worked in gun shops for too many years to accept round-counts mentioned across the counter at face value. Nothing personal guys, but the true number of rounds fired is typically a quarter to a tenth of the asserted number. I teach law enforcement patrol rifle classes in the summer, and I see how much work (and have done it myself) it takes to run 1,000 rounds through a rifle. If your buddy says “Yea, we went to the range this weekend and put a thousand rounds through each rifle,” he’s exaggerating. And if he isn’t, you do not want to borrow any of his rifles, as a thousand rounds in two days is enough to smoke the barrel

 

This guy trys to write a informative, technical article, but he ends up giving us a non relavant history lesson and some semi technical info all mixed in with his own knowledge opinion. Those last two sentences (in bold) made me laugh though. Going through 1k in a weekend is easy, guess theres alot of AR barrels out there that are "smoked" lol.