Neat MB. And what do you mean, Good To GO? I always thought .223 and 5.56(NATO) were the same.

In YOUR line of work, this should be a good weapon for ya. I was talking to a trooper the other morning, and he carries an AR15 He built instead of an issue .223. The issue rifles were made by someone he isn't all that fond of but can't remember the name. Oh and YES, he did have to get everyone to sign off and then qualify with it.

Oh and Yeah, I figure that thing is loud.

What is your opinion of the Kel-Tec PF9 9mm?

Randy, the dimensions are similar but the 5.56 NATO round is higher pressure. With that barrel you will be able to run .223 and 5.56, but don't run 5.56 in a .223 barrel.

They are not exactly the same. You can use .223 in a 5.56 chamber and should not use 5.56 in a .223 chamber.

Oops. Posted at the same time. What he said.

Randy as mentioned A 5.56 will fit in a 223 Chamber but it can cause an over pressure issue. A 5.56 chamber will work just fine with both.

What cliber it says on an AR lower doesn't mean much. The issue is what the barrel and upper is. Most of mine say multi cal.

I can slap a variety of uppers on the same lower receiver from a 9mm to a 50 Beowolf.

Well I don't have to comment on that. Thanks guys

There is also another .223 chamber on the market, called .223 Wylde. It's supposed to be cut to shoot 5.56 safely, but it's also optimized for accuracy using either 5.56 or .223, since using one chamber or the other effects the performance. I think Bushmaster offers it IIRC

Yessir! I was about to mention that but I didn't want to add to the confusion!

I thought the Wlyde Chamber was 223/5.56 and designed to shoot the longer round like the 77 grain bullets which sometimes won't chamber in a 5.56 due to OAL. Usually on a precision rig.