I shot the 140 Sierra in my 7mm rem mag and they usually left a large exit. I switched to the 140 solid base which left a less dramatic exit. Both had DRT effect.
Of the powders you listed, I'm partial to IMR 7828 ssc. I can get close to 3000 fps with a 150 partition from a 22" barrel. My loads start at 0.040 off the lands due to the size of a model 70 magazine box. Oal on my loads hover around 3.340 +- 0.005.
I put an old, say 40 yes old, M8 6x on a 270 win, last month. It wouldn't adjust and the point of impact wandered around. Sent it off to Leupold for repair. They're sending my 6x back along with a VX3HD 3.5-10x cds duplex. I guess they couldn't fix the M8.
My first load for that Bob was a 117gr Sierra gameking with 48grs of H-4831 @ 2975 fps. Killed my biggest south Texas buck with it. A bunch of coyotes and Javelinas went down too.
I sent an M8 6x back to Leupold last week. I sent a Vari X II back last year with an adjustment ring that wouldn't turn. Got it back a few weeks later, put it on my 7mm rem mag and zeroed it in with my favorite 160 accubond load with no trouble. The work order showed they replaced ocular...
I have been shooting 62grs of Grand with a 150 gr Partition with a Nosler case and Fed 215 Primer. My results show a consistent clean burning powder except there seems to be a 25 to 30 fps increase in velocity when the temps get into 90s. My initial loads had average velocity of 2995 fps and...