Man, THAT's the truth!
Conflicting info, fo sho'. Definitely a lot to wade through.
And really, all I wanted was some advice on building one...
Building an AR is definitely fun. FInding a lower from a private party is on my list of pretty tough tasks. All lowers, other than the afore mentioned un-machined castings, have a serial number and are typically sold as ‘incomplete’. They are sold that way so a reseller that completes one and then sells it out his door as a rifle is required to collect the excise tax (I believe it is 11% of street value) on the completed gun.
All the legal statements notwithstanding - the BAT effing E is a tax collection agency. They likes their moneys. They make rules and hoops just so as they can collect their moneys. They have agents that wear full entry level gear and carry silenced machine guns so they can interface with a non compliant public.
You do not want to cross their line.
In my opinion, unless you watch the video, like the excellent Brownells video linked previously, and feel like an AR is in your wheelhouse to competently build technically speaking, you will find it cheaper to buy a factory built gun. Factory built is lower cost because they waste very little in the process, they can piece one together with almost no labor overhead and their parts cost is guaranteed less than you can get the same parts for since they buy them by the thousands.
If cheaper isn’t your thing, then building one is a fun and rewarding task. An AR is like a chevy, everyone makes something for them and most of the parts fit pretty well within spec as long as you stay with quality manufacturers.
I wouldn’t be surprised if you couldn’t find a private party lower though. You may have to bite the bullet and complete your gun with a FFL transfered one. So what. Certainly takes the guesswork out of the history of your lower.
Not like the BAT effing E doesn’t know who you are already :^)