His job dates back more than 150 years and is one of the biggest tourist attractions at Edinburgh Castle.
Sergeant Dave Beveridge is the District Gunner, responsible for firing the one o'clock gun.
The tradition dates back to 1861 when it was fired at one o'clock to give the ships docked nearby a time signal they could use to set their navigational equipment.
Sergeant Beveridge considers the job and important part of keeping up military tradition. He said:
"People are generally interested when they come up here because they like the traditions of Great Britain... you tell them the history and they're actually interested, they think it's great."