OK, I'll be the dumb one and ask if a standard 308 cartridge will fit in a 308 express lever rifle? If it is custom fit- what is the possible longevity of this cartridge? I am a lever rifle kind of guy and this rifle sounds awesome. I just do not want to buy something that is going to be hard to find ammo for. I would also like to see Marlin make a 26 inch octagon barrel for the 30-30 round like they have for the 45-70.