Killswitch, don't take it the wrong way, but what you are asking is kind of like asking "What engine do I need for my truck ?". Depends. are you going to run Nascar truck series, drag race, or tow a large trailer up mountains? It's really all going to come down to what you want to do with it. A few questions you have to know the answer to is, what platform you want to put your .308 in semi, bolt, or single shot? What is your mag box length going to be, if this applies? Do you want to change anything to possibly be able to seat your bullets out further so you can gain velocity? Do you wish to shoot any VLD's, or Hybrids? If this seams like a lot, it is. if you want to be able to run anything and everything and it shoot pretty good, well that is what the factory has came up with in a SAAMI chamber. This way it can handle most everything. Kind of like a factory engine in a truck, it's not great, but it isn't to bad either.