I sent off a Colt upper and freefloat tube and asked Steve to put on a RRA NM barrel(they had the best price on these I have ever seen too) using my parts. One week later and my assembled upper is back in my hands. Thats what I call good fast service. I would highly reccomend ADCO to anyone thinking of buying parts or having some work done. I don't work for them I'm just passing on my experiance.