One of the bigger changes in Right-to-carry laws over the last couple of years has been the drop in number of hours required for training
The research in More Guns, Less Crime indicates that the main effect of longer training periods has been to reduce the number of people with permits. States with longer training periods have had smaller drops in violent crime rates as a result of fewer people being able to defend themselves and deter attackers. I know of no evidence that increased training is associated with reductions in accidental gun deaths. The only benefit is that increased training is associated with a somewhat larger reduction in multiple victim public shootings. However, since this is such a small share of total murders and since the effect of more training is associated fewer permits and more murders, the net effect of longer training requirements is increased crime even in this case.