I'm beginning to research (shop) for my first AR, and am undecided between a 16" and 20" model.  I plan on using the rifle for 3 Gun matches.  Any advice would be appreciated.  

Theo :-)  

20" is better than 16" for 3Gun.

The 16" barrels sometimes have problems making the "minor" power factor with 55gr factory ammo.

The long gas sytem in a 20" (or 20" cut to 18") will smooth out the recoil impulse somewhat.  Get a good brake/comp like JP's BC Comp and you are good to go.

-z

I purchased a 20" Colt Hbar for my first AR, or rifle of anykind for that matter. I came to the conclusion that I wanted a lighter rifle really fast. The 8 1/2lbs that the Colt weighs is at the outer edge of where I would like the weight to be. If you add anything to it now your too heavy. I added a TA-11 ACOG, 19s Arms mount, 3 point CQB sling and a Harris lightweight bipod and I was at 10 1/2lbs. That was without a magazine full of ammo which I believe is about a pound. It was way to heavy. I decieded to go with the Bushmaster Modular model which starts out at 6.3lbs and it made all of the difference in the world. Being shorter and lighter it is allot easier to move around and much less fatiguing to aim freehand.

Damn!!  For a minute I thought that TT was back.