A nail gun has a body, a breach assembly, a triggering device, a safety assembly and a magazine. The safety assembly has a safety lever and an activating beam, both of which are required to be activated to selectively engage the triggering device to allow the nail gun to perform a nailing cycle. When the nail gun is operated incorrectly, the safety assembly does not engage the triggering mechanism so the nail gun is prevented from performing the nailing cycle. The magazine is mounted in the breach assembly and feeds fastening devices into the breach.