There was an argument about gun crime vs. violent crime on Facebook yesterday.
Violent Crime victims (per 100,000 pop.)
UK : 2500
US : 500
Gun deaths (per 100,000 pop.)
UK : 0.25
US : 10
It might only be me, but if these figures are correct, looks to me like overall, forgetting the sensational headlines, guns prevent violent crime at statistically low cost.