I have one of the R700 40th Anniversary editions with the 5R barrel. Shoots great, but the barrel is nearing the end of its life. What do you think of the 5R barrel and is it worth replacing it with another 5R or should I go with something else? If 5R is the way to go, who makes a good one? If I were to have a 5R barrel made, what twist rate should I go with for the heavy bullets 175gr to the heavy Berger 230gr?