Simple Question, Not so simple Answer.

[cstone]

A Sturmgewehr 44 would be pretty awesome. Then I could actually admit that I truly own an "assault rifle."

I would need to stock up on the Privi brass and learn how to reform .308 brass, but it might be worth it if I hit the lottery.

[XC700116]

One I'd actually shoot, an AI PSR Kit with an S&B 5-25 PMII on top and TBAC suppressor, And about a 4 other barrels that I'd add to the mix in different calibers. Or a JP LR-07 with a custom chambering in 6X47 Lapua, topped with an S&B Super Short.

for a pure giggle stick, M2 or minigun.

and Collector/Value gun something along the lines of what TimK said, not sure on that, then I'd probably sell it, and buy most everything listed above and go have a ton of fun with it.

[Icecoldviper]

The 30mm in the A-10

[asmo]

Mk19. No question.

Why? Because fuck that guy, and everyone in his general vicinity.

[asmo]

The 30mm in the A-10

GAU-8/Avenger. Excellent second choice.

[n2877]

The 30mm in the A-10

That gun is insane. I swear it sounds like a long and loud fart when the fire it. I've heard it even slows the plane down a little when fired, not sure if that is true.

[n2877]

BlasTech E-11 would be my choice. ( yeah that's right I'm a star wars fan )

[HoneyBadger]

I've heard it even slows the plane down a little when fired, not sure if that is true.

Technically it is true (Newton's 2nd law) but it is not an easily measurable amount. The 30mm rounds weigh less than 1lb each, if I remember correctly, and the plane can weigh as much as 40,000lbs when loaded up. Even firing several hundred rounds over a course of a few seconds is hard to account for because of the changing dynamics of the aircraft's flight profile, angle of attack, thrust levels, drag levels, coefficient of lift, etc.

[cstone]

https://en.wikipedia.org/wiki/GAU-8_Avenger

The A-10 engines were initially susceptible to flameout when subjected to gases generated in the firing of the gun. When the GAU-8 is being fired, the smoke from the gun can make the engines stop, and this did occur during initial flight testing.[2] Gun exhaust is essentially oxygen-free, and is certainly capable of causing flame-outs of gas turbines. The A-10 engines now have a self-sustaining combustion section. When the gun is fired the igniters come on to reduce the possibility of a flame-out.[15]

The average recoil force of the GAU-8/A is 10,000 pounds-force (45 kN),[3][16] which is slightly more than the output of one of the A-10's two TF34 engines (9,065 lbf / 40.3 kN each).[17] While this recoil force is significant, in practice a cannon fire burst only slows the aircraft a few miles per hour in level flight.[15]

[Aloha_Shooter]

As I understand the question, it's not "what gun would you choose if you could only have one gun?", it's "what gun would you add to your collection if you could have anything you want?".

If that's the question, I'm with thvigil11, give me a perfect, complete Singer 1911. If it's a gun to use rather than just have for a collection, give me the BFG-9000



Oh wait, you meant a REAL gun? Sorry, can't pick just one ...