I was looking into getting one of these uppers and was wondering what would be the advantages or disadvantages from choosing one or the other I can get the 11.5 w/flash for about 350 from a friend.Is this a good price or should I just save up and get the M4 A3 direct from Bushmaster Any advice is greatly appriciated

The shorter one flashes a lot more, and the velocity on it is pretty bad. If its a good upper, and you just want a toy, it should work. The M4 contour barrel heats quickly, so i would get a 16 inch hbar. The 14.5 inch barrel is a little on the short side of the velocity spectrum.

If it will be a fun/range gun only, get which ever is easier. If it is something you may want to build that has real world use, the 11.5" barrel has very limited use. You are comletely wasting a good 5" of barrel space for a extra long flash hider that doesnt work nearly as well as the Phantom.

With the 14.5" upper and Phantom, you get a lot more velocity behind the rounds you fire, and a awesome flash suppressor.