Want to build a 308 on my long action rem 700. I have ptg bottom metal with an accurate mag that's labeled 300 wm. I made up some dummy rounds and they feed pretty reliably, I don't need 100 percent reliable feeding but wouldn't mind it. I see they have a 30/06 mag would this work better? I'm left handed and have an action and stock so I would like to make this work the best it can.