Ok so I own a Remington 700 SPS tactical .308. This is my first bolt action rifle and I am clueless as to important considerations when purchasing a high end stock. I am planning on buying a Mcmillan A4 stock. I don't have a clue as to the barrel contour I need to order and do I need to have an idea of the next barrel I will replace the stock barrel with? Do I need to buy the detatchable magazine system I plan to use and have it inletted when I buy the stock or can that be done later? Please any advice would be a huge help!!! Sorry for my ignorance! Thank you!