I am getting ready to build a tactical comp gun and already have some parts. I have a trued and squared Remington action. I also have a new 6mm 1-8" barrel that will finish at 28". My question is should I keep the 6mm barrel and chamber in something like .243 or should I go with a 6.5 barrel? I plan on using aftermarket bottom metal and a McMillan A5 stock.