Thread: 223 or 5.56

Well from what I can read, there is also a second pressure pulse (apparently) So the first is the pulse that overcomes the bullet's inertia to leave the case, the second is when the bullet touches the lands, hopefully we all know about this? Many testers and equipment dont measure this second one which maybe the key one for the 556/223 issue as its so highly strung. So simply the books I have from knowledgeable ppl prepared to write about it in a book (ie are legally then liable as opposed to some knowall on a forum with a name like "jacksmackhead" who's "never had an issue") say you have to check and if need be ream the chamber to make it safe in all conditions. Add in that an AR15 gets extremely dirty, more abused and hence and hotter than a bolt action (who does 30~60 round mag dumps from a 223 boltie? in a minute?) so yeah sure. ie compare apples with apples.

My stance is to be safe and err on the side of caution, especially as there seems to be no real gain for most people.

"I am not going to even hazard a guess at how much higher" Some of the tests I have read suggest an AR15, dirty, on a hot day and abused (so hot) can exceed the bolt's test pressure done when new. Now this test pressure is done 1 or 2 times and never meant to be repeated and not 30 rounds (or more) from a mag dump.

On the other hand of course we dont see lots of pictures of f****ed AR's and ppl missing bits of hand / face.

There is a good kindle book series by Patrick Sweeney Gunsmithing the AR15 vol1 and vol2 and The Gun Digest book of the AR15, vol1 to 4, 6 books in all, worth reading IMHO.