Ditto the previous comments on length suggestions 5.5 - 6 inches. I like 6 a little better - the site radius is just about right for me open sights
Also, when it is scoped, it feels a little better balanced. When the barrel gets long you start to feel like you might as well be carrying a rifle.
Go 6" and if you decide to shoot her open sights for a packing gun, you'll not be dissappointed.