Yeah, you should make a Metal Storm weapon.
http://www.metalstorm.com/
Video:
http://www.metalstorm.com/release/future-weapons-400k.html

Can only the guy you provide use the gun? I can't seem to find the backpack in tools or anything but the gun is in weapons.

Yep; only that guy, and he comes with the backpack and gun. Like other things in the to do list with question marks, I'm interested in feedback about that.
Should the backpack be equip-able to any actor? Should the backpack be replaceable, or refillable?

I think any actor should be able to carry it, and that it should be replaceable.

Or do it the old way and remove the need for a backpack!

Egh, not a huge fan of roman candles, and I certainly need no more than 8000 rpm. Maybe if the concept comes in handy to make another function I want, but I won't make one just for the sake of making one.

No way. That's half the point of the mod, the unlimited magazine and limited ammo reserve.

Sorry to have asked for opinions and gone with the one thing that no one suggested, but I think I'll try to make the mags refillable and wearable by any actor. Might also try making the method compatible with multiple ammos, dunno. As said before, I'll also have operator velocity inheritance removed as an exploitable feature.

I still like the idea of an overheating-sensitive gun, but that idea will wait for later. It certainly won't be applied to the GAU22.

Well, there still is their 40MM Grenade Launcher version

Replaceable yes, refillable only with bunker system, and you have to detach to refill.

Wouldn't that cause MORE of an overheating problem though? A problem with caseless ammo is that there's no casings to take some of the heat with them upon ejection.

It would make the mechanisms simpler though, which would allow higher firing rates and cause less malfunctions. Still, dat heat...

Could have bull♥♥♥♥ hightech heat sinks.

If you're firing bullets and not shells, I think heat shouldn't be a problem so long as you're not operating with a burning torch strapped to the barrel.

You obviously don't know what you're talking about then.

Or you could go old fashioned and have a liquid cooled barrel and chamber.

I never said it'd solve the heat problem. I thought I was suggesting a possible way to have high fire rate with a heat gauge to limit firing.
You could possibly have quick switching barrels; if the heat gauge is maxed out it forces a reload.

Interesting theory. I cordially invite you to come here, and press the side of my Winchester 94's barrel against your cheek after I've fired it 20 times in moderately quick succession. Afterward, you may want to reevaluate your ideas on the matter while I get you some ice.

Anywho, the overheat thing in the mod wouldn't be because it's realistic and I need to be realistic anyways, it would be included because it would be a balancing feature, and potentially unique, interesting, and/or fun.