So I am starting to look at/want a rifle scope for my M&P15T.  None of my friends have had any experience with the Nikon P223 line, so I thought I would fish for some opinions on here.  I want a magnified scope, but I'm not planning on reaching out beyond 300yds or so.

What, if any experiences have you guys had with the Nikon?

I have a P223 fixed 3 power on a walkaround hunting AR 15 that I really like. It has a series small circles on the lower half of the vertical reticle (BDC) that are supposed to be calibrated to the 55gr Ball load. I would say it is pretty close out to 300 yds. Certainly close enough for most shooter/rifle combos. I like the glass, nice and crisp, no edge blur on my lens grid. For the money they are vary good scopes. I would assume the same applies to the 3-9x as well. My preference is for smaller and lighter so I tend to use more fixed power scopes on my rifles. All the Nikon glass I have used over the last 10 years have been well made and plenty  durable for normal hunting/shooting duty.

Imho, either the fixed, or the variable model should be an excellent choice for what you want to use it for.

I just put one on and for the money it seems to be a good scope. For 300 yds. it'd be perfect.

I had one for awhile - decided to go the red dot route but it's a great scope - very accurate, clear glass, etc.  
the guy who bought it from me is winning shooting contests with his buddies out to 250 yds

I have one and love it. Buy with confidence. 9x won't be enough to punch super small holes in paper but it will definitely reach 300.

I had one and it worked great, held it's zero and the glass was pretty good to boot.