Worked with them a lot 20 plus yrs ago . Primary is loading the bullet in the sabot , flat base is best from memory , the bullet must be seated straight . I used a rigged setup to check runout . Then there's loading the sabot with no or min run out . I tried powders from pistol to rifle . I was also using a 30-30 for testing . 4198 and reduced 4895 worked but only if the bullet to sabot to case runout was min . I tried corn starch , baby powder , graphite etc ,trying to get uniform release of bullet from sabot .
It also pays to weigh the sabot . After you shoot try locating the sabot , a tarp in front of the muzzle helps , this is to ensure uniform release of the bullet . The distance of the release varies , velocity and twist will determine how well it releases the bullet and how far from the muzzle .
Getting a 2" group at 100" was a good group . Always a flyer .
It also pays to weigh the sabot . After you shoot try locating the sabot , a tarp in front of the muzzle helps , this is to ensure uniform release of the bullet . The distance of the release varies , velocity and twist will determine how well it releases the bullet and how far from the muzzle .
Getting a 2" group at 100" was a good group . Always a flyer .