The salute will be used to celebrate the 150th anniversary of the Royal Australian Artillery and will be the first time the Portland cannon will fire in nearly two decades.

In Warrnambool, a volunteer garrison at Flagstaff Hill will dress in the uniform of a colonial artillery battery to honour the occasion.

The period-accurate clothing includes an original 'exploding grenade' hat badge, garrison artillery buttons and a webbing belt.

While most elements of the day will be kept historically-accurate, about 500 grains of black powder would be used for the salute - a far cry from the original 13 kilograms required in the 19^th century.

Garrison member Ken Ryan said only blanks would be fired.

"They won't let us play with live stuff, they're worried we might drop one lot into the caravan park," he said.

"If we used 13 kilograms there would not be a window within a kilometre of the fortification.

"When we do fire the 500 grains of black powder, when you stand up near the hills, you'll feel the ground vibrate. There'll be plenty of smoke, plenty of noise - we learn a couple of new words each time from the ladies in the crowd."

Group member and former soldier Steve Ivey said despite the safety measures, it would still be a "ground-shaking" moment.

"It's very exciting, especially since the Portland cannon hasn't been fired since the '90s," Mr Ivey said.

"They used to say it could never be done. Well, that's about to change.

"At Flagstaff Hill, we also assigned roles to volunteers at the cannon - including ranks and orders - to recreate the scenario of a colonial artillery battery as it carried out drills."

Warrnambool mayor Richard Ziegeler praised the efforts of volunteers in maintaining the heritage-listed cannons - two of 26 sent from England in 1866- assigned to defend Victoria's gold.

"The garrison at Flagstaff Hill is an important part of Australia's military history and it has been kept alive thanks to the dedication of Flagstaff Hill staff and volunteers," he said.

But while the cannons may be well-loved, their significance is often glossed over.

Little known are the tales of the Crammond and Dickson Shield and the Sir William Clarke Trophy, or the success of the Warrnambool battery.

Mr Ivey said the city's garrison held the honour of best shooters in Victoria.

"There were two major prizes for cannon shooting in Victoria," he said.

"There was the Clarke trophy - the rules were if a battery won it three times, they would get to keep the trophy forever.

"The Warrnambool battery won it three times and you'll see on the trophy that Warrnambool was the best. Nobody seemed to know where it went - turns out the army used to use it as a centre piece on their dining-in nights. There were officers who went down trying to pinch this thing. Eventually the Warrnambool guys decided the only way to keep it here was to donate it to Flagstaff Hill where it is today.

"The other was the Cramond and Dickson Shield. It was named after a business here which had all the buildings at the bottom of Liebig Street. There was also a Dickson who was a lieutenant in the artillery. They had a shield - it was given in about 1966 to the army to use as a shooting trophy. The army has it but we're not exactly sure where it is at the moment. I see letters from the historical society asking for it back, but the army's replied we're not getting it back.

"We're trying to get it back and photograph it so we can complete the history of the cannons."

He said the importance of Warrnambool's cannons could not be understated.

"They've actually found evidence there were privateers before the forts were built from Russia that were seriously planning on coming down here to raid a rich gold port - it was actually on the table," he said.

"Because of the Crimean War, there were further scares Russia might go to war with Britain. The threat was real and despite some people thinking they were a paranoid lot in the 19^th century, they weren't. By the time they decided to build all the forts, the Russians thought it wasn't such a good idea after all.

"So we can argue on the basis of that, the cannons were a resounding success because they stopped the Russians from attacking.

"Then, if you go back to the 1860s, we had the American Civil War going on. A confederate ship came down to Melbourne and their ship was repaired and refuelled and provided with provisions. After the civil war finished, they imposed sanctions on Australia for supporting the confederates.

"So Australia paid for it after the war was over for supporting the wrong side. Before them, you had the French - that was another reason to be frightened. The French were looking to colonise and Napoleon sent down expeditions to gather information about Australia.

"The perceived politics at the time were that since we were a gold-rich nation, we needed to defend our coastline. Every colony needed to worry about their own defence until we had federation. If we were to get invaded, they'd come from the sea, so we needed to defend our coastal areas."

The importance of the cannons was not lost on Flagstaff Hill volunteer Ken Ryan, who said Saturday would carry a particular significance for him.

"My great grandfather was in the original regiment," he said.

"There's a picture of him at Flagstaff Hill. He's on the left hand side about the third one down in the middle with the moustache. His name was Edward Carter."

He said it was incredibly important to keep the tradition of cannon-firing alive.

"I think it's really terrific," he said.

"It's great to be involved in something like this and the whole bunch of us enjoy what we do up there and it's really good some descendants are involved too.

"It's part of our heritage - they were there for a purpose and it's good to keep it alive. I've been involved for about five or six years now."

View the salute at:

Portland - 9am

Port Fairy - 12pm

Warrnambool - 3pm

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