Bob has hit the nail on the head. I had a 280 AI and was shooting 63.0g of powder and with the 7Mag was shootig 65.5g of powder. The 7 Mag got 75 fps more, probably due to variations in barrels.
I have discovered R#25 with the 154g SST's which is pushing the 154's at 3200+ with extreme accuracy in the 7 Mag. The 154g SST is really a fantastic deer bullet when you start getting out there a ways. I hunted a fruit tree that was 300-325 yards away from my stand. I killed two bucks in their tracks at 300, and one jumped straight up in the air doing a summersault, landed on it's belly and never even kicked at 325 yards. The 154 SST's demand to be jammed into the lands for extreme accuracy in the 7 Mags that I have shot them in.
Recently a fellow on the fire suggested that I try Retumbo with Fed 215's with the 162g A Max and glory be, shot three shots in a single hole at 3100 fps, Rem 700 sporter-26" stainless barrel. He said that customs got 3200 fps with a tighter chamber.
I use vias muzzle breaks on my 7's and see the bullet impact on the deer's hide...recoil less than a 243 sporter.
