After how many times asking the same question does it take to make this a sticky? One second searching this site or the internet answers the question, usually with pictures.
Please sticky this!
A true OPERATOR can distinguish milspec vs. non by just the smell of a rifle.
The easiest way to tell, just by looking at them, is to look where the threads go into the receiver. The outside of the commercial tube will be the same diameter as the outside of the threads, on a mil-spec diameter tube the threads will be greater than the tube diameter.
So that techno weenies can brag that thier gun, that they never actually shoot with and only pose in thier underwear so the girlfriends, (or maybe thier moms, not sure if they actually have girlfriends) can post the photo's on the web, ...."Is all milspec!"
It really makes no difference unless you want to put the fancy "Milspec" bits and pieces on for the "Tactical photo shoot"!
Scott
Just look between your legs. If your #### hasn't fallen off - your gun is milspec
One way or another, doesn't make a difference. Many com extensions are made of the same materials as their milspec counter parts. This is a gap that has remained since the AR was made commercial, before it become popular to the point that any part of any variation of the type (be it military or law enforcement) could be acquired commercially. Why they haven't standardized? Profit. Plain and simple. Everybody wants something better, something original, authentic and special. The Milspec product market offers just that, as you can almost literally own a firearm that is down to specifications 95% exactly the same as it's military/law enforcement counter part. Now how isn't that cool? However when it comes to performance and otherwise practicality, the improvements of milspec over commercial is marginal. Nonetheless the extra expansive options make for owning an AR quite the freedom of choice in personalizing your firearm and boosting consumerism.
All depends on which side of the coin you look at it.