One chamber
Preferrably a constant air flow interrupted by the bolt (less chance of messing up the timing).
The loading is a problem, I was thinking about taking a look at how the miniguns load BBs and see if I can come up with something from that.
If I can use the bolt to interrupt the air flow I ...

Miniguns are VERY hard to make.
You need to be very skilled at building and designing pneumatic cannons and you'll also need a machine shop

I understand that they are pretty difficult to make, I do have access to a machine shop but I also have an idea to make one a little easier.

If you just ...

I'm wanting to make a small minigun. Small enough to fit on a large RC car (1/8 or 1/5 scale)

OK I just recently acquired an interest in this particular field so I'm not fully informed. My experiences thus far include loading and shooting.

I do however have the needed technical skills to build one myself I just need info on parts and certain other things.

I'm wanting to build a BBMG ...

ok I'm really surprised no one has mentioned this yet. the design you're discussing is used primarily in paintball guns, check the trigger and bolt setup on a paintball marker and you'll find a way for full auto,[/i]