I have a rem 700 SPS in .308 right now. I have a new friend that is a machinist/gunsmith and I decided to change the gun up a little. I cant decide what caliber I want to change the rifle to, I think I want to stay with something with the same boltface as the .308. I was thinking I want to keep it short and light, and maybe something not so popular. I have no idea about custom rifles as I have never had one before. Any tips or suggestions?