I'm with the other poster about the need or desireability for non-organizational full-auto fire. However, I disagree that possessing the parts and an AR-15 is illegal. What the memo says is that if you have parts that you can place into an AR-15 that will make it full-auto, you indeed have a machine-gun even in disassembled form.
To make an AR-15 full-auto with M-16 parts requires the drilling of the receiver to accept the auto-sear. Doing so would make the gun itself a machinegun. Possession of the Drop-In Auto-Sear in combination with M-16 parts is bad, though, as this can literally be dropped in. Possession of all of the parts required and listed below along with an undrilled receiver is NOT illegal.
Just a point, you have to have the following parts stockpiled:
1) M-16 Bolt Carrier
2) Auto Sear with pin and spring
3) Auto Selector
7) Firing Pin (I Think)
** In place of the M-16 Carrier and Firing pin, Bushmaster sells a modification part that installs on your AR-15 bolt carrier to allow it to trip the auto-sear.
To stay legal, you cannot put ANY of these parts in your gun or they would make the rifle a machinegun.
Additionally, you must have a drilling fixture, drill, and the proper drill bit. It'd also be a good idea to make sure beforehand that your receiver isn't one that's blocked or bastardized (Colt) so that you cannot modify the gun.
You might wanna ask yourself one question. "Do I feel lucky?" Personally, I don't feel lucky. Full-auto has limited applications mostly in formal, trained units or during ambushes. Both of these can occur if the proverbial feces hit the fan.
We may or may not worship God, but John Moses Browning made sure we can choose.