AR advice needed

[Delaware_Dan]

I posted this on another forum but I would like to get as much input as possible.

For all the AR experts out there, I think I might be ready to get started on one. I have never really liked the AR platform but with all of it's versitility it's starting to grow on me. What do I need to know? Can I slap any complete upper on any complete lower? What if I want a 9mm upper, will it generally come with everything I need to just put it on? I am completly in the dark here so any help is welcome. Upper and lower brand suggestions are appreciated as well. Ideally I would like to have a 5.56 upper (that will also shoot .223 right?), a 9mm upper, and a 5.7 upper. Sorry for the overload of questions, I just never thought I would be asking them. Thanks for all the help in advance.

-Dan

 

[DMK]

I would like to have a 5.56 upper (that will also shoot .223 right?)

Yes, that will work with .223

Can I slap any complete upper on any complete lower?

Mostly yes, but there are some exceptions. Some 9mm uppers require different hammers. I think there is a way to get a hammer and upper combo that will allow you to swap back and forth, but I have no experience, so I hope someone who knows will chime in with their own experience on that.

I do have a 7.62x39 upper and a 22LR upper than I can swap onto any of my lowers. No problems there.

Try poking around this forum for more info about the pistol calibers:

http://www.ar15.com/forums/forum.html?b=3&f=15

Don't forget the 9mm FAQ:

http://www.ar15.com/forums/topic.html?b=3&f=15&t=108261