Owning a fully automatic weapon (machine gun) would not fit with Jehovah’s Witnesses viewpoint on keeping a firearm for personal protection. If a Witness keeps firearms for hunting to supplement his diet with wild game that is acceptable even for elders. Keeping weapons for self defense opens one up to becoming bloodguilty through accidental or unnecessary discharge of that weapon. Of course accidents can happen when a weapon is owned for hunting, but when the gun is kept for use against humans the congregation takes a dim view of it.
Fully automatic weapons dispense ammunition at a rapid rate when the trigger is held in firing position. The energy from the exploding charge of one round is used to chamber and fire the next round. Legal ownership of such a weapon is very expensive and requires an intensive background check and other screenings by government.
It is highly unlikely that a Jehovah’s Witness would ever jump through the hoops to acquire a machine gun legally. And if he should possess one illegally that would be a big issue since obeying the laws of the land is very important part of being a member in good standing.
Since it is absurd to think one would use a machine gun for killing game,most likely the ownership of such a weapon would fall under the category for protection and use against other humans.
Such ownership is a personal decision.
However a JW who chooses to arm himself in such a manner would be restricted from many privileges in the congregation as can be seen here
Christians respect others’ consciences. (Rom. 14:21) If it became known that a member of the congregation kept a gun for protection against humans, some fellow believers might be shocked, even stumbled. Love moves us to put others’ interests ahead of our own, even when that means putting aside what we may feel is a legal right. —1 Cor. 10:32, 33; 13:4, 5.
Christians strive to be exemplary. (2 Cor. 4:2; 1 Pet. 5:2, 3) After receiving Scriptural counsel, a Christian who continues to keep a gun for protection against other humans could not be considered exemplary. He would therefore not qualify for responsibilities or special privileges in the congregation. The same applies to a Christian who continues to carry a firearm as part of his secular work. How much better to seek other employment!