Ok Noob question here sorry for my ignorance in advance.  I got one of the AA mid-length blem gun  and wanted to turn it into a tac driver.  Does the fact that it's a piston gun change the fact that I need to get a different type of barrel?  Or do I get a standard mid length barrel that I could use for a piston or a DI gun? Any other suggestions to aid in my project gurus ? I'm more of an AK guy but couldn't pass up the deal so your alls help is appreciated.

You got a great deal on that rifle and the barrel is mid range in quality.  That said, you need to define what you are wanting for precision.  AR precision is improved by barrel quality and matching high quality ammo to the barrel type but these improvements are usually "stacked tolerances" that are beyond most shooters ability.  There is not a lot of quantified data that says either DI or piston systems are more accurate.  

For your rifle, I would try some 62gr match ammo and a good optics and see if the rifle is meeting your "precision" criteria.  Should be 2 MOA or better based on your ability.    

If you decide to exchange barrels, you will need to replace the gas system (with either a DI or AA piston kit) because the AA gas block is pinned to the existing barrel.  Based on your decision, you may need to replace the upper receiver (the AA upper has a smaller hole for the gas tube) and BCG; so the best option may be having a second complete precision upper.  The AA lower is mil spec and will accept any mil spec upper.

Good luck,
fatkid

It's pinned on, but the pins knock right out, then the block slides off.  If the match barrel is mid, it should pin on, if the diameter of the barrel is the same.  The notches for the pinned block need to match that on the barrel.  I believe they do.  I looked into this myself, but mine shot very well with the hand loads I used.  I doubt without a better trigger and all the other variables I can shoot any better.

True, removing the gas block is quite easy; finding a replacement barrel with matching machining, very difficult.  If you decide to use the same gas block, a gunsmith or one of several companies will be required drill the holes for the pins.  The machining is pretty difficult but if you are feeling froggy: http://www.ar15.com/forums/t_3_118/412289__ARCHIVED_THREAD____Tapered_front_sight_pins___How_to_drill_.html&page=1

fatkid

You will definitely need a better trigger for sure. It is essential to accuracy. Right up there in importance with the barrel and ammo. One of the many Geissele triggers are the way to go.

That's what I was afraid of, that it would be too complicated.  I guess I will just buy a trigger for her then a rail and go from there.  I live close to Bud's store and pulled about 8 or 10 of these rifles out and had issues finding a blem on any of them I guess that shows my ability to overlook things or AA quality control.  I haven't got to shoot mine yet but look forward, I hope she's a good shooter.  Thanks for the help, I may just look at a DD MK-12 to plink around with and shoot yotes.

The factory AA barrels (Voodoo Tactical melonited) are not "mid level" from what I've heard. They are on the upper level (thanks to the melonite). I've heard VERY good results from the Voodoo barrels and mine does quite well (mid length AA, both a "kit" and a factory version) and will outshoot your ability unless you're a VERY good shooter.  If you're not familiar with the benefits of Melonite barrels, google it and there's lots of info. It's the way to go, IMHO.  You've go an excellent barrel there.... see what you can wring out of it.

Cursed by a low price point

The stock barrel is a great barrel.  I'd install a Samson Evolution FF Rail on it and call it a day.  Those are the rails that AA uses on their rifles.  Since you have the mid-length, your gonna wan the 9" or the 9EX.  Have fun with your new rifle.