bafsu (and me), also highly recommend
http://palmettostatearmory.com/ good bunch of guys, prices are very competitive with the same stuff BCM and Brownells have. Just an FYI and a very reliable source.
When I built mine, I had a bug telling me "I'll get a super dee duper trigger later"......I used a Bushmaster Lower parts kit on my P.O.F lower, and with the stock Bushy trigger, was a match made in heaven... It is very snappy, take up is minimal and reset is as crisp as fresh garden celery.
You do not need a gunsmith, as posted just a few tools. Do you plan a Delta Ring or free float? I like the free float, but it's a matter of personal preference.
Rock River sells complete uppers, made in the USA, and are very reasonable as well. I nit picked with a Colt HBAR cold forged barrel, Daniel Defense upper, Yankee Hills free float carbine handguard, and A.R.M.S 71 flip up BUIS.
Not many tools needed. and AIM Ar-15 wrench is $20 it's a multi tool of sorts for the AR. Check out Brownells "How to" videos on the AR... a small punch kit can be had pretty cheap. A razor blade holds the front take down spring in place for the pin to be installed you don't need that tool....
I actually used this vid to help. Went without a hitch..... Little blue masking tape, urethane, or solid rubber mallot, for the bolt release pin. and everything else is no problem...
Good luck, post pics..It's nice shooting one you built for the first time....
Shameless Papa Plug for my Frankenstein:


Before the vented YHM handguard.


all started with this
