To start I would like to give my apologies if this is in the wrong topic area.  I am new to long guns and especially ARs.  After holding a bushmaster AR at the range a few days ago I had to have one.  But for 900 I dont think so.  I am in the process of trying to buy one from a board member and will be seeing the AR FTF before final Purchase.  So I would like to know what are the tell tale signs to excessive wear and tear.  How to be certain the weapon is functional w/o firing, and anything else I should be mindful of before I hand over the cash?  The weapon in Question is a Bushmaster 16" A3 HBar with an A2 flash hider and std. A2 stock with 1000 to 1500 rounds fired through it.  Lastly, being and A3 does this mean the carry handle is removable to reveal a picatinny rail? I apologixe for my ignorance or possible stupidity in some of my questions.   I am greatful for your responses to my inquiries.  

-MTS-

Do a simple function check (Info Here) and also check fit & finish..

1500 rounds is nothing...   the AR (if not abused) should look damn close to NIB.  The good thing is with used AR... as long as the lower is in great sharp, everything thing else can be replaced.  Look closely at the lower... check for stress cracks, etc.  But if it's a BM...  it should be good alloy.

When looking at a used firearm... you really need to go shoot it

Lastly, being and A3 does this mean the carry handle is removable to reveal a picatinny rail?

Yes, the A3 designates a removable carrying handle with a flat top underneath.  As with any used gun look for abuse and abnormal wear and tear.

CD

if its a stock bushy, look for the shiny bbl too

you will see the excessive wear on an AR; check for cracks on any of the metal and plastic parts

Thanks guys I really appreciate your help!