Apparently I'm just not meant to own an AR-15, because every time I try to order parts, I end up with someone taking my money and then refusing to send me my merchandise.
The last time this happened, it was from someone I knew over Facebook. This time, it was from an internet vendor with an actual physical address and everything. Both times, they've tried to scam me and refused to communicate when I asked, quite reasonably, "Hey, where's that stuff I paid for?"
To everyone who thinks I am paranoid for not showing my face on the internet: this is one of many, many reasons why I feel that, honestly, I'm not paranoid enough. I'm obviously far too trusting when it comes to believing people will actually send me what I pay for.
And this is the main reason why I bought an SKS: because I suspected I'd never get my AR built, and I wanted something to fill the "semiautomatic rifle" slot in my firearm inventory. At least this way, I have one from each of the major food groups.
I will go into greater detail, including the name of the vendor, as soon as the credit card company assures me that the chargeback is complete. Oh, believe me, I am going to vent my spleen and name names, and hopefully no one within the sound of my voice will buy from this company ever again.