Could be smaller than a normal power cell, point is it isn't 2mm big. The caliber only applies to the bullet not the cartrage.
And as I've said
three times now even if its the size of a standard cartridge, it's still ridiculous.
And a Magazine is what you put bullets into, it loads into the gun from the bottom. A clip loads into the top of the gun. So an individual bullet or powercell is not "A magazine" onto itself.
Obviously a power cell is not a "magazine" in the conventional sense, but it's depicted in the same way.
The Energy weapons in Fallout 3 and New Vegas have ejection ports. So there goes that idea of yours that they don't need them. The simple fact is there was no need to be that detailed when showing the guns back in the originals.
No, they do not. Where do you see the ejection port in this video of the gauss rifle:
http://www.youtube.com/watch?v=jWwsBq48gxk
Or on the laser rifle:
http://images.wikia.com/fallout/images/9/90/AER9LASERRIFLE.png
Or on the plasma rifle:
http://images.wikia.com/fallout/images/6/6c/PlasmaRifle.png
Of course there's no need to have one on energy weapons because that wouldn't
make any sense. You'd only need one if you had a disposeable power source attached to the round (which doesn't even exist in any energy weapon), which is totally unsupported by evidence.
That's your opinion. You tried to use canon to prove your point, and that didn't work out. It is very reasonable that in the Fallout Universe they combined a powercell with a 2mm projectile. After all a coil/rail gun right now is Huge, yet in Fallout it is rifle size.
Repeating a failed argument is not a very good strategy.