Weapon idioms

Cannon

Cannon fodder

Loose cannon

Gun

Gunning for someone

Hired gun

Jumping the gun

Smoking gun

Son of a gun

Sword

Speak with one's sword

Meant one's reply would be in the form of swordplay rather than words.

In Reginald Barclay's fantasy holoprogram, he answered Data's suggestion he yield while fencing and Barclay replied, "I will speak with my sword, sir." (TNG: "Hollow Pursuits")

Sword of Damocles

Trigger

Pull the trigger

Trigger (something in) someone

Weapon

Secret weapon