I am getting my Browning A-BOLT rebarreled to a 280AI. My gunsmith called and said he is about 2-3 weeks from chambering the barrel. It is a 26" 1:8 Shilen in a #4 or 5 contour, cant remember. I plan to shoot 160-175grn bullets with RL23 and Peterson cases. Question is, should I get it throated for the 175's, 160's or leave it to SAAMI specs? Any advice is appreciated.