Just won my bid for a used but like new CTR MAgpul moe stock! The guy that I bought it from said he thinks it is mil-spec but isn't 100% sure. I asked around to see if my m&p AR is mil-spec buffer tube and was told that it is but not other parts of the gun. Just going to have to wait until it arrives and try it out, these go for $95 so I thought I got a great deal on this stock. If for whatever reason it doesn't fit it will go right back up for sale again