Gents, I admit to be a throwback to another age and don't wanna step on you younger guys feelers in any way, but just gotta say here, it will never ever ever never get cold enough for me to walk around in the hinterlands of the UP with something that looks like I borrowed it from my daughter...
I guess I'm semi-young (early 40's), but I don't think that the Moab 6 I recommended looks like something borrowed from a woman. But, hey, maybe it does.
Oh well. It goes across the back like you wanted, but because its a sling pack it's really easy to bring it around the the front to access the pistol quickly.
Pic borrowed from the web, but this is the one I have:
I use mine when riding bike to work and when hiking. I don't "wear it around town".