If you have a ten twist Barrel you will have troubles stabilizing anything heavier than about 190g. I haven't tried to do subs in my 308, however the platform isn't that important as long as you recognize it's limitations. Like poor ignition, inconsistent velocities, hang fires. You just have too much case capacity with a 308, IMO. That being said, if I were to want to try some 308 sub-sonic loads I'd start with Trail boss. It may be your best bet to limit those issues, maybe Red Dot, or Unique, but you'll have to use some filler to hold the powder against the primer. Or better yet a Ruger ranchhand 300blk is designed to do sub-sonics well. I would look really long and hard at sub-sonic hunting bullets that are designed to perform down to 800fps. Regular cup and core bullets tend to just fold into a banana shape and exit in an unpredictable fashion, or just flip around and exit base first with no expansion. I've shot about a dozen feral hogs with a suppressed 7 twist 300blk and a 250g outlaw state subsonic expanding bullet. You can easily find them with a quick search. It's designed to open at sub-sonic velocities into six segments that spread out from the main wound and the base of the jacket and lead core punch through and expand. I am sending them off at 1020fps. It train wrecks them. I zero it at 100 and just hold on the body out to 150, I've never had an opportunity to shoot any further than that. There are other places that make sub-sonic expanding bullets as well, but I've never had a reason to try them as the outlaw state 250 has worked flawlessly for my purposes.
