I've decided to buy a 38/.357 revolver. a gun both my wife and I can shoot. I was going to get a 3" barreled sw686, but the store has a used sw66 in 2-1/2' barrel. this is for home defense and I do not "plan" on shooting .357, mainly 38's or 38+p's. I'm not sure which to get and can only buy one not both. I've read some people said "pre lock" is better or some prefer the internal firing pin rather than the firing pin on the hammer. Any advice?