A BB gun uses compressed air to push a round steel "BB" out of a smoothbore barrel. It does not have the power, range, or accuracy of a firearm.
Mainly in the stock
No such real item.
Stock dimensions and sights
Caliber and bore are used interchangeably nowadays. There are technical differences you can find in the dictionary if you wish.
A sub-machine gun fires pistol cartridges. A machine gun fires rifle rounds.
There is no difference in that either can be used for the other job. Of course there are hundreds of types of guns around in the building industry.
One barrel
there is a gun iny pants loL
Stock and sights.
2mm in case length.
none.
You have answered your own question.