I personally use a glock40sw with fiocchis fmj major factor for back up the glock is ligth small you can repit fire on the running shoots and is very easy to point just using the front sigth so i vote for the 40sw and for the GLOCK.I use a 44magnum of6 or a king cobra 357 of six inches when they are my first gun but for back up use a glock.juan