Instead of just working as a retail assistant, he started fixing guns and doing repairs. He had started reloading when he was 13, encouraged by his father who had got him into hunting.
After about nine years, it got to the point where he was spending his nights at home doing gun repairs and it was "too much".
He told Mr Kunac he could not do both but he would like to continue with the gun side, so he branched out on his own, setting up a small business at home.
He was "very fussy", which was important when he was doing his work, as it meant the rifles worked well, he said.
It was a busy time of the year with the opening of the duck shooting season in early May.
Duck shooting was an extremely fun time, with many hunters taking their children to experience what was a "culture thing for New Zealand". It was particularly strong in Otago and Southland, he said.
Increasingly, hunting and shooting enthusiasts wanted a rifle that was "a bit more special" than simply
off-the-shelf.Mr Jefferson likened it to "buying a flash car, changing the wheels on it and making it look better".
"Kiwi men are like that. They love having something a little bit different that no-one else has got," he said.
So he was doing custom rifles, replacing the stock and barrel and building a rifle that was often "a bit lighter and flasher".
Hunters were taking a lot more gear into the hills and were keen to save weight, so the lighter the rifle, the better.
Long-range shooting had "taken off" recently and some enthusiasts were not even hunters. Rather, they enjoyed "getting out there and testing their skills".
Mr Jefferson preferred the hunting side rather than long-range shooting — "I don't get too much enjoyment out of shooting targets" — but he acknowledged it had made his hobby a lot easier.
He would rather be out looking for animals but it was not all about the kill.
"I enjoy watching animals more than people sitting at home thinking they are animal lovers. We're pretty passionate about animals; this country has got huge assets in its wild animals," he said.
He believed the Government did not realise how much money was spent on shooting and hunting in New Zealand.
There were "millions of dollars" spent during the hunting season, and he was keen to see animals managed correctly.
Mr Jefferson still wanted time to go away and do some hunting himself, sometimes taking sons Regan (17) and Mathew (8), just like his father did.