Any good 7-08 bolt gun with a custom barrel should be printing under an inch with 139s - 140s.
I always start with Nosler BTs, then Sierras or Hornadys. Never monos at first. RL15, Varget, or RS BG. Should be grouping well, the 7-08 is not a fussy cartridge. If it won't group with NBTs then you have other issues.
