Running a 16"1:8 twist barrel pistol length gas system in a AR platform. Have 130 to 168gr bullets to load for subsonics. With imr 4227, imr 4198, cfe blk and h110. Is this a good starting point with my powders i have. From what i have read it should be. I will work a load from high to low to find the sweet spot. I have adj gas block, springs, buffers and low mass bcg to play with if needed. Looking to see if any 300 blkout experts have loaded this way with good success.