The Gun Blogs

Where have you been all these years?

Add these to your list:
US
http://www.injuryprevention.org/info/data.htm\
http://www.nhtsa.dot.gov/
http://www.nsc.org/
http://www.cdc.gov/ncipc/osp/usmort.htm
http://www.cdc.gov/ncipc/osp/mortdata.htm
http://www.cdc.gov/ncipc/wisqars/
http://www.cdc.gov/mmwr/preview/mmwrhtml/ss5002a1.htm

US Crime Info
http://nationalatlas.gov/crimesm.html
http://www.ojp.usdoj.gov/bjs/
http://www.ojp.usdoj.gov/bjs/homicide/homtrnd.htm#contents
http://www.fbi.gov/ucr/ucr.htm

http://www.ncjrs.org/
http://ojjdp.ncjrs.org/ojstatbb/ezashr/asp/Off_Selection.asp

http://www.albany.edu/sourcebook/

Australia
http://www.abs.gov.au/ausstats/abs@.nsf/web+pages/statistics?opendocument
http://www.aic.gov.au/stats/index.html

UK
http://www.homeoffice.gov.uk/rds/
http://www.the-stationery-office.co.uk/
http://www.homeoffice.gov.uk/crime-victims/
http://www.crimestatistics.org.uk/output/Page1.asp
http://www.scotland.gov.uk/Publications/2005/12/13133031/30316

UN
http://www.unodc.org/unodc/en/crime_cicp_survey_eighth.html

And poke around inside those links - lots of data gets ignored or misrepresented, and providing the original unvarnished info is definitely preferable to guessing.