Well, kind of first build. I say that because I didn't build the upper, that, I bought complete. But I did build out the complete lower. I've been collecting the pieces to do my first build for about 2 years now and finally took the time to get it all assembled. I watched a step by step video on YouTube to walk me through the process. Overall it was a fairly simple process, one I took slowly, just to make sure I didn't mess up. I did slip up a few times along the way, but nothing serious, just back up and repeat the steps. The pivot pin was a bit tricky since I didn't have an install tool, but YT saved the day again with a method to do it without the install tool that worked just fine. Thankfully everything fit in place just as it should. I've heard that sometimes tolerances are out of whack, but I don't think I encountered that here. Nothing had to be forced and nothing was loose. The action appears to be smooth and the trigger seems to function well. Here is what makes up this build: * PSA Blemished Lower (no issues with mine, I know some folks have had trouble with them) * Defense Package LPK w/Ambi safety * Magpul STR Stock - FDE * Magpul MOE+ Grip - FDE * Tom's Tactical Buffer Tube Assembly * Alpha Shooting Sports .223 Wylde Upper with 16" fluted barrel and Keymod Rail in FDE * Magpul PMAG in FDE I'm hoping to get this to the range for a test fire in the next few weeks, if I think about it, I'll report back on this thread as to the operation. I still have a few mods I'd like to make to this build, including upgrading the trigger, adding a Magpul B.A.D. lever, switching out the charging handle - possibly for a BCMGunfighter, and swapping out the trigger guard - I'd rather have something curved. I'd like to add a grip of some kind to the rail eventually as well. For optics, I'll be mounting a Vortex Crossfire II 3-9x40 with BDC reticle on a Burris AR-PEPR scope mount. For a later build, I'd like to build a complete upper as well. But that will have to wait just a while. My thanks to everyone here at NWFA that gives information and encouragement to us newbie builders, I may never have attempted this without your input.