I had sent my AR-10 back to ArmaLite for the upgrade.  In less then two week I had it back in my hands.  I also had the muzzle brake removed and had an flash compressor put on.  Now I am waitting on my CAR stock.  The rifle is an AR-10A2 that has an 16" barrel.  I even order two packs of 5-20rd mags with my order and got them very fast.  I have not shot the as of yet, but will soon.  The rifle look good with good with the black compressor with the heavy SS barrel.  I know this post is worthless without pics, but I have not had the time to take pictures yet.  

So if you need the upgrade, do it.  

Bob the Nailer.