Gary McKay never knew what the regular patrols through the jungles of Vietnam would bring.
He went to Vietnam in April, 1971, as a Second Lieutenant and commander of 11 Platoon, in charge of the lives of 35 men despite being just 22 himself.
Men who he had only met for the first time a few months before they were assigned to a base in Phuoc Tuy Province.
On those treks along trails through the jungle, they walked in single file, each soldier searching through the foliage for any sign of North Vietnamese Army (NVA) soldiers.
Sometimes contact would come on a daily basis for a week, each of them close-quarter engagements where the enemy soldiers were as few as as 15 metres away. Close enough to see the expressions on their faces. Certainly close enough to see what happened when the bullets they were firing hit the enemy.
"It's scary. It's noisy. It's at times chaotic. After you've been there and done it, you hope no-one else has to do it.''
That would never be graphic, like a hundred movies have made death in war appear. Usually, all McKay would hear was a grunt and the enemy would fall to the ground. He would later describe it as like cutting the strings of a marionette puppet.
Other times, they would leave the jungle and return to base having not seen the enemy. Sometimes this would happen for a few days in a row, soldiers walking through the jungle with sweat - maybe from the heat, or the tension - trickling down the side of their faces.
They would spot signs the enemy had been along the same track - trees along the path bent back, or a fresh bootprint in the soil filling with rain - so they knew they were nearby.
But they wouldn't see them. Once, this happened for four weeks and the tension kept building - McKay says they were as taut as violin strings when they got back to base, wondering if tomorrow would be the day when they would come under fire.
Then there was the day of September 21, when, as McKay describes it, "the sky fell in".
They were part of Operation Ivanhoe, looking for the 33rd regiment of the NVA, who were believed to be heading towards 11 Platoon's base camp. On patrol on September 20 and 21, his platoon hit NVA soldiers along the jungle paths, before being called to help 12 Platoon, who had found a large element of an NVA regiment in a heavily fortified bunker and was preparing to attack.
"We'd never heard the amount of fire that came our way," McKay says.
"It reminded me of what blokes had told me about the battle of Long Tan. We're on our guts and we're were fighting for our lives, heavily outnumbered - probably 8-1 - with the enemy dug in.
"There was so much noise. The radio operator next to me had the radio shot off his back. I had my hat shot off.
"It was pretty intense."
Within the first half-hour of the battle, three of McKay's four machine gunners had been killed and the fourth was mortally wounded and would die on the chopper ride to hospital.
McKay realised the platoons needed the firepower of those machine guns to beat back the North Vietnamese.
"There wasn't enough time for me to tell someone to get forward and get the guns going, I could see what needed to be done, so I did it," he says.
"I went forward, I recovered the gun off two of my dead machine gunners. I got the gun working and had to use the gunners' bodies as cover from fire.
"Once I got the gun going, I was able to stop the enemy attacking us."
One of his soldiers on the right flank did the same thing and, together, they managed to thwart the enemy assault.
They received the order to pull back to allow artillery to hit the area and, in another skirmish later that day, McKay was hit in the shoulder, totally blowing away the joint and making his arm useless.
He was pulled out of the firefight and choppered to hospital the next day. He would never return to the war in Vietnam.
But during his 12 months in and out of hospitals while they repaired his ruined shoulder, he received the Military Cross for gallantry because of his actions on September 21, 1971.
"His display of courage and steadiness in battle rallied his men," the citation reads, "and although he was badly wounded in a later action, he continued to encourage his soldiers in a manner that reflects great credit upon himself, his regiment and the Australian Army."
While this year marks the 100th anniversary of Gallipoli, 2014 also features another military commemoration. Fifty years ago this year the first Australian combat troops were sent into Vietnam, which should see Vietnam Veterans Day on Monday take on added significance.
McKay, who now lives in Kiama, was part of the last battalions to serve in that war. He was choppered out just a few months before his battalion - 4RAR - left the country.
A few years earlier, walking through the jungles of Vietnam was the furthest thing from his mind. He didn't even know where South Vietnam was - he was more interested in surfboat rowing and playing rugby.
But then, in 1968, his number came up - literally - in the televised lottery that decided which men were conscripted. The process resembled a bingo draw and, to today's eyes, seems a slightly comical way to decide something so serious.
"It's just like a big chook raffle where they've got a machine and marbles come out," McKay says.
"One saying what month and another one says what day and away they went.
"It was a lottery. Australia couldn't afford to have universal conscription, with everybody going in, so they had what was called selective national service. Depending on how many people they would draw birthdays out of a three-month period. They did that four times a year.
"My birthday came up and in I went."
He says he understood the idea of being called up but what irritated him - and a lot of other men whose numbers had also come up - was the randomness of it all.
"It was the luck of the draw," he says.
"If everyone went in, you'd have nothing to bitch about but because not everyone went in, it gave you a reason to have a complaint."
Because he had finished high school with good marks, he enrolled in officer training, graduating six months later as a second lieutenant. He went on to spend time training other soldiers.
While he - and all soldiers - had the option of doing their two years of compulsory military service in Australia, McKay asked to be sent to Vietnam.
"I realised I only had six months left in the military and I wasn't going to go to Vietnam," he says.
"In a perverse sort of way, that cheesed me off. I had my life interrupted, allegedly for service to support what was happening in South Vietnam. so I wrote a letter and said: 'OK, I want to go to Vietnam as a reinforcement'."
He got his wish, being assigned to command 11 Platoon in October, 1970, meeting them for the first time at the Jungle Training Centre in the Gold Coast hinterland.
"I trained with them for six weeks, then we went up to Townsville and spent the next four months doing final preparations for going to Vietnam," he says.
"So I had to get to know my platoon real quick."
At just 22, the lives of his men in his hands, he was greatly helped by his experienced sergeant, who had fought in Borneo, Malaysia and had just completed a tour of duty in Vietnam.
"He was the man I looked to for advice," McKay says.
"Whenever I made up a set of orders, I would always go down to his tent and run it past him. He'd pick the eyes out of it and tell me where I might make some adjustments.
"When we were out in the field and I wanted to make a new set of plans, I'd always run it past him. We were a team - just because you're the second lieutenant doesn't mean you've got all the brains."
After Vietnam, Mckay stayed in the military until 1995. During his time, he was posted to the Royal Military College, Duntroon, in 1983. The move saw the start of a second career for him as writer, starting with a memoir of his Vietnam experience called In Good Company.
"The only reason I wrote In Good Company was that there wasn't any autobiographies on Vietnam on the bookshelves and the cadets that I was teaching at the Royal Military College, they had no idea what it was about," he says.
"I gave a lecture once at the college and some of the academic instructors said: 'You ought to put that in a book'. So I did, and bugger me dead, it became a bestseller. As a result of that, the publishing house Allen & Unwin said: 'You better write another one'."
He now has a tally of 14 books to his name - many of them about Vietnam.
His time in Vietnam he refers to as "a war in the shadows" because of the jungle foliage. It's also a time that has never left him - even decades later.
"I can tell you there's no glory," he says of war.
"It's pretty scary. It's noisy. It's at times chaotic. After you've been there and done it, you hope that no-one else has to do it.
"Even 40 years down the track, you don't forget those moments in combat when you're fighting for your life and you've got to shoot someone. You never forget that horror. It stays with you forever."