Work colleagues and parents were among the 300 people who signed a petition pleading for leniency for Martin Wynn Davies, head of Ysgol Gynradd Deiniol in Marchwiel, near Wrexham.
Ten years on from the shootings at Dunblane primary, the 58-year-old was sentenced to four years at Mold Crown Court last week, after pleading guilty to 14 charges relating to 10 handguns, two rifles and ammunition.
Davies asked for nine similar offences involving four handguns and five rifles to be taken into consideration.
The minimum sentence for some of the charges is five years, except in exceptional circumstances. But Judge John Rogers, QC, said Davies's positive record and the manner in which he had co-operated with the police investigation were exceptional.
Steve Parry, acting chair of governors at the 179-pupil village school, said Davies "was a dedicated professional who supported the school, but unfortunately for him his hobby was found to be outside the law. He has tremendous support still at the school and in the local community. It is an unfortunate and sad case."
Davies, who was due to retire next year after 23 years as head, has been suspended since police raided his home and that of his elderly parents in April. The court was told the conviction would cost him his job. Education authority officials will now meet the school governors to discuss Mr Davies's future position.
The court was told that Davies disposed of his handguns following the Dunblane shootings - but built up a new collection of handguns and rifles.
He had also inadvertently taken ammunition to school in the boot of his car.
Davies was brought up on a farm and had his first weapon at age eight. He was said to be obsessed with guns and had an encyclopedic knowledge. But, while he held a licence for some weapons, others had been held illegally - and insecurely.
The judge said: "I accept that you had possession of these firearms and the ammunition because you are a collector of firearms, and in particular relatively antique firearms. You had no intention of misusing them, nor at any time did you attempt to do so."
But the intention of the post-Dunblane legislation was to prevent firearms being in circulation.
Robert Trevor-Jones, defending, said Davies had a long and successful teaching career and had given his all to the school. He accepted he had made fundamental and repeated errors.