Sicen Sun says he was an enthusiastic video gamer who only ever intended for the replica firearms - which included an imitation sub-machine gun - to be used as props.

Judge Penelope Wass in the NSW District Court on Tuesday sentenced the 28-year-old to a 12-month suspended sentence after finding the overall risk he posed to the community was very slight.

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"No gun was loaded nor was it capable of being loaded with ammunition," she said.

"They were being used in fantasy role-play games."

Sun had 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.

He was arrested in 2017 after he posted one of his imitation weapons for sale for $1 million negotiable on a Facebook buy, swap and sell group.

"With 20/20 hindsight I just realise how silly, idiotic, stupid and naive my actions were," he told his NSW District Court sentence hearing earlier in August.

"I could not even begin to contemplate that a hobby would land me in such strife."'

The judge accepted Sun never intended to sell the Facebook-listed imitation for such a high price and that he instead, like any craftsman, craved recognition for his work.

She did, however, note that if one of his replicas fell into the hands of criminals "it could be used to invoke fear of it being a genuine weapon".

"The replicas were not stored securely in the offender's home making them arguably more likely to be stolen and fall into the wrong hands," Judge Wass said.

Sun had been assessed as having a low risk of re-offending and was now all too aware of the consequences of possessing replica weapons, she concluded.

Australian Associated Press