I've got some data that has given me the most consistantly accurate 5-shot groups at 100 yards. I only had 12 of these bullets left to work with and the velocity isn't up there were it should be, but when I get some more bullets I'll have more data with increased powder charges.
Here is the load,
Primer - W209
Sabot - MMP
Bullet - Hornady 300gr. XTP MAG
Powder - IMR-4198, 50 grains
I fired all twelve of these bullets, two 5-shot groups and a 2-shot group. The two 5-shot groups averaged 1.952" at 100 yards. This is the first time I have got under 2" with two 5-shot groups. One of the groups had four shots that made one hole in the bullseye, the group size for these four shots is an amazing .460", thats under half an inch!
The velocity of this load is 1884 FPS.
I'm going to up the powder charge when I get some more bullets, I'll let you know what happens.