Just got a new tscustoms rifle. Now I need to load some rounds for it but my problem is its a 18" rifle. My 26" 260 loves 142 smk with h4350, should I go to a faster burning powder like varget or cfe I also have some benchmark and h1000 I plan on shooting 100 amaxs and/or 123 system possibly some 120 amaxs depending on how the other 2 shoot anyone have any suggestions for me?