If you just want to dump rounds downrange, with either a AR or AK, buy a slidefire. I got mine for $150 shipped.

Keep in mind HK isn't the only full auto ... have you considered other platforms? Like an UZI, the MAC 10 or Cobray M11, or MP40 ... Maybe a grease gun?

There's other options out there ...

A couple weeks ago I added a transferable Cobray M11 with a LAGE upper for what I considered a reasonable price for the times ... Just 3-4 years ago they were going $2500 - $3500 now they've doubled and more, and like all the rest of MG's they are performing better than better than the stock market and unlike the stock market, they are pretty much a sure thing as it would literally take an act of Congress to put an end to the NFA.

I second Kimberkids post. Having a choice back in the day between the UZI and the MP5 I liked the UZI better. But that's a matter of personal choice. A decent UZI runs less than half the cost of the MP5.

I'm with Lyman & JoshNC ... while I can't say I've had 35k worth of fun in the 5 or so years I've had 2 of the 3 of my MG's but I didn't buy them as investments, I bought them to shoot and enjoy ... the fact that they have more than doubled in what someone would pay for them now is just a bonus.

If the nfa were to dissolve today I would be just ecstatic because then I could make all my hk's f/a instead of having to switch my sear pack from gun to gun, same goes for my m16 ... I could then make my AUG, Scorpion 61 & EVO automatic not to mention my SiGs ... one thing for sure tho ... I'd have to get a part time job to support my ammo habit