There have been quite a few of us using and talking about the combination of Shock Wave 250 gr and the Short Black Harvester sabot with which any good reloading primer will work, I have heard that there is a bad lot of TC primers out doing a lot of misfires so I would avoid them until the problem is resolved. While some people are still using 777 the best results with this load are being produced by Blackhorn 209 most of the time.
Also realize that most TC guns require a break in of 50 to a 100 shots before they produce there best groups. If you are in a hurry for results at long range about 50 strokes with JB bore paste on a good tight patch replacing the bore paste about every 5 strokes will polish your bore.
Also 110-115 or 120 gr of Black horn depending on your particular gun and elevation will match up with your Omega BDC. Lee