I'm building my first AR. I've owned a couple AR's in the past and I used one while in the Marines but, never built one. After the conversion I did on my Saiga 7.62 I decided to give it a shot. Parts List: AXTS AX556 Lower Receiver BAD Combat Ambi Selector Switch - Short Throw Geissele Super Dynamic Combat Trigger VLTOR MUR-1A Upper Receiver Rainier/AXTS Raptor Ambi Charging Handle Geissele Mk4 13" rail in Sand or KAC URX3 Rainier Arms 16" Select Barrel Rainier Arms Low Profile Gas Block Battlecomp 2.0 Troy Folding BUIS - FDE Nickel Boron BCG JP Enterprises Silent Captured Spring Buffer Assembly Magpul K2 Pistol Grip or Standard MIAD I haven't decided on a stock yet. I was thinking about the ACE SOCOM stock, the long version, which would impact the decision about the pistol grip. I was honestly thinking about ordering a K2 for my Robinson XCR as well and testing it out. I ordered my lower from AXTS in Salem about 2 weeks ago. Lead time is 60 to 90 days. I just got in my Geissele trigger from Tier One Tactical in Cali. I was dreading paying double the price for the VLTOR upper when just by chance I found some in stock for a few hours at Strong-Side Tactical in Colorado. I managed to pick one up for $199.95, which is MSRP. I am kicking myself for not buying a couple more but, shrug, I didn't want to be greedy. It should be a nice rifle and I've figured it's probably gonna set me back about $2800. Hopefully parts will start coming in soon so I can start assembly. I was originally considering the Geissele Mk1 rail because the rounded sides have been reviewed as being nicer to handle but, I like the new MK4 rail. My only problem with it is that unless they do the Keymod version you won't be able to attach any extra rails. Also, who knows when they'll be released.