The reduction of 21% took the total from 647 in 2010-11 to 514 last year in Scotland.
Police cleared up 70% of all offences alleged to involve guns last year, up 2%.
Justice Secretary Kenny MacAskill welcomed the figures published by the Scottish Government.
"These figures represent great progress in tackling the menace of firearms offences in our communities. Year on year the number of crimes involving guns on our streets is dropping rapidly," he said.
"The message appears to be getting across that guns put lives at risk and anyone caught using them can and will be punished heavily. This is complemented by great detection, educational and preventative work done day in, day out by our police officers across Scotland to make our communities safer."
Injuries and deaths from firearms fell by 14% from 111 to 95.
Air weapons accounted for almost four in 10 offences, down slightly from 234 to 195.
Guns were involved in five killings in 2011-12, compared with three in the previous year. Attempted murders, vandalism, serious assaults, common assaults, reckless conduct and robberies involving a firearm all decreased.
The use of shotguns and pistols reduced over the year, the figures show.
Strathclyde Police recorded the largest proportion of firearms offences, while Lothian and Borders Police recorded the most vandalism offences.