Sicen Sun, 28, was arrested in 2017 after he advertised one of his imitation weapons for sale for $1 million on a Facebook buy, swap and sell group.
He's since pleaded guilty to charges including possessing a digital blueprint for the manufacture of firearms, manufacturing a pistol without a licence permit, and possessing an unauthorised pistol.
"With 2020 hindsight I just realise how silly, idiotic, stupid and naive my actions were," he told his NSW District Court sentence hearing on Monday.
"I could not even begin to contemplate that a hobby would land me in such strife."
Sun, who dresses up as pop culture characters and was previously described by a lawyer as "something of a fanboy", said he meant for the replica firearms to be used as costume props.
