Algodoo

I don't have much experience in building such devices so I want to hear anyone's opinion about possibility of making it real.

bad

this wouldnt make a machine gun beacuse most machine guns can fire about 3.4 bullets a second but i would make a great silent shotgun

The exit has to be tangential to the circuit because the bullet flies away tangential so that it can leave without any problems.
but it's a good idea

i like the concept, it's like a circular railgun, really nice

if you work on it hard enough, i have no doubt that it's plausible. of course it goes without saying to use caution. i agree it would be hard to make it a machine gun with a single loop, but could work in a spiral formation. you could disguise it as a garden hose!
anyway if you do make it don't forget to link it for your loyal subscibers

7/10

but i love the idea

this is basically the LHC (particle accelerator) as a weapon
mind if i try to make it better (using attraction)
instead of a hinge to push the ball

it would be possible to build, but very hard because the steel ball would have to be the exact size of the tube, and the releasing system would be hard to design

but its deffinitly possivle