ZRider
I forgot what gun you might be shooting, but I am using the regular MMP Blue sabot in my 50 cals and I am also using the XTP (less expensive and I am not shooting extended ranges). When you place the bullet in the sabot it does st in the bottom of the sabot as yo think it should but as you push the bullet to the powder the bullet wil seat in the sabot. Harvester now makes a 'crush rib' that is somewhat thinner and easier to load in tight bores.
The XTP's shoot like a dream, I have used them on ground squirells - in Idaho we can not use anything less that a 44 cal on big game from a ML so I have no experiance with them shooting deer - but others do.