I load for 9 different guns in 300 win mag and in all cases the TTSX's shoot well seated .050" off the lands but you should be using RL22 and Fed215 primers. H1000 shoots good but not as good as the RL22 or even RL25. But you definitely should move to the Fed215's (if you can find them).
I thought "Woods" was shooting my Encore with a 300wm by his comment! That's the same combination my rifle likes best.
Barnes requires you to shoot the TTSX .030 to .070 off the lands but recommends starting at .050. and "grit" hit the nail on the head. Don't put to many variables it to the mix all at once. You also have to keep in mind that the closer to the lands you are the high the pressure cup is, "keep track of your velocity's" so you know when your reaching un-safe limits.
Honestly, I have found in some rifle / bullet combinations that the highest velocity isn't always the most accurate. Not only that, you may want to lower the grain of the bullet a tad to like the 168's. They shoot better in my WM than the 180's do. Realisticly most "not all" 30 caliber rifles perform best at that grainage. Just look at the .308 Winchester. Don't be affraid to slow it down a bit, you may be surprised by the out come. I know I was. One other powder that works good in my WM with the TTSX is IMR4831 but RL-22 has a more consistant performance shot to shot.
My work-ups consist of 5 shot strings in 5 grain increments. I run 1 powder with 3 different bullets, 1 case brand and 1 primer to start. All information is then run threw a ballistic program. Next I change up the primer only. Than the case. Next I take the best of the best and mess around with the seating depth in 3 shot strings. If I am still not satisfied with the results I move on to another powder choice and start over.
If I am using new cases I fire form then twice before I get serious and pay close attention to case prep, headspacing, & runout. No more than .002 runout. Headspacing no more than .002 but look for .001 anymore than that your working the brass more than needed and your running in the danger zone. To much HS can be very dangerous and hurts accuracy so be carefull!
Good choice with the Barnes if you take your time working up a good load. Best performing bullet on game out there bar none! Because they do retain nearly 100% of mass upon impact you don't need to run the heavier grain bullets like you need to with other bullets!
WRG