Jean Gilson-Levi was stopped at Dover whilst carrying a single-barreled semi-automatic weapon in the boot of his car.
The clergyman, 52, of Penfold Road, said that he used the weapon to shoot in his native Belgium.
He has been given a 20 month suspended sentence for two years as well as a £1,000 fine and £500 fee to cover costs.
The leader of the Restored Covenant Churches of God admitted two counts of illegally owning a shotgun and later made an attempt on his own life.
Judge Adele Williams told him he had "an inflated opinion of his own importance".
She went on to say that he thought he was "better than everyone else, better than the police or the UK authorities."
Kent Online has reported that on the day he was arrested he had also been stopped driving and found to be without a licence or insurance.
He was fined by magistrates.
The judge has given him until the end of December to pay and has confiscated the gun and ammunition and placed a total ban on him possessing a firearm in the UK.