Nice vid BCG... Thanks... 
Im kind of in the same boat. Been ready for quite awhile to either do a build or buy one pre-built, just been super busy. When I slow down for my winter-spring break Im going to get into this. If I buy one already built I suppose it would be a good idea to equip myself with the tools needed for assembly just in case and for repairs or mods plus when I decide to do my own build I will already have the tools on hand.
In the video in the link above. The tech demonstrates using a special tool to install the spring and the front take down pin detente. He mentions that he made his from a punch. I had some quarter inch rod and was going to make the tool from that stock and then I looked around and found a cheap Chinese made Phillips screw driver with the correct diameter in my tool box. A minute with a dremel cut off tool, and a couple of minutes at the drill press drilling a small hole, and presto, I had the tool. Made installing the spring and detente pin a simple task. Proud to say that I didn't launch the pin once and didn't cuss it a bit.
An easy and cheap "tool" for the front take down pin and detent is your average $1.25 clevis pin from Ace Hardware (or your hardware store of choice). Worked great when I built my .300 Blackout.
I don't know if all lowers have it or not but my spikes has a tiny hole in the front takedown. I was able to compress the spring and hold it in place with a needle in the hole.
I would recommend ALG defense rails, they use shims and even come with a barrel nut wrench that doesn't require a torque wrench. I have 2 of them on my sbr uppers, both were less than 120.00 bucks and they are the best rails I have used. I have spent big money on larue rails, DD rails etc, but the ALG is the best IMO.
Just a quick update. I fired my AR for the first time tonight, worked perfectly. I didn't lose any pins or springs during the build, but I did ruin a free float barrel nut, I bought an economy armorers wrench and it didn't fit well. I thought I could make it work, but it slipped and I took a chunk out of the nut. I had to re-order the nut and a quality barrel wrench, that and the weather (unheated shop) and my MS, slowed me down. I'll sight her in tomorrow. I highly recommend building an AR if you have ever thought about it. It's not hard at all and a lot of fun. Thanks for all the help and advice from you guys.
Congrats! You should get some better weather later next week. tRidiot's build party thread and this thread have me considering putting one together from scratch. I really don't 'need' one, and I certainly don't need another caliber to reload, but it certainly is tempting. I don't think I'll get to make the build party, but I sure would like to be there to watch and learn!
