Happy to oblige!
Give CCI 200s a try. I Always find that mag primers don't work as well as non-mags in the 270.
You may have to search for the sweet seating depth for the BTs.
The velocity is about where you want it, i'd think. You may wish to give Alliant 4000 MR a go for a bit more boost. Works great in my 270 w/140s @ WSM velocities.
Oh, and I use 7828ssc w/CCI 200s for 3200 FPS MV and 140 Berger VLDs.