Sub sonic

No, not unless your rifle is specifically set up for subsonics. There's a huge difference in gas pressure and volume between full power 308 and subsonics, even with very heavy bullets, and it's not the same as the small capacity case of the 300 Blk that can be set up to run both.
 
You might try light buffers and a reduced power buffer spring. I recently read about a company offering a kit with different alloy and steel weights for use in the buffer and Tubbs sells a reduced power spring.