Re: 2960 in a 27", my experience showed about 100fps for a 3" shorter bbl in a 55,
so in the 47, I figure you are getting about 25 per inch +/-, so about 100-130 or so more than a 22" sporter.
2850 in a 22" w/140 is moving in a small 6.5. Nice performance.
Comparing the 140 Berger .612, dropping from 2950-2750:
200 yd zero
400/500 yd clicks:
18/28 vs. 21/33
The initial 200fps MV diff drops to 169 at 500 yds....
Energy 1554/1328 at 500 yds...either capable of doing fine as far as I am ever likely to shoot.
Even a 130 Berger/2850 will do 1250 lbs at 500, drop 20/31 clicks at 400/500 w/200 zero.