I shoot the 140 Berger out of a 270 WSM at 3307fps, I haven't got it on enough game to know all the variables but so far under 400 yrds they go in and then shread everything inside of a 8in circle and you find the jacket under the of side, DRT
The 270 WSM get's there in a flat hurry, I've got almost 800 rounds through mine and it still surprises me some times, and man it hits hard. The first couple deer I shot with my dad spotting and he was just shock at how hard they hit, kinda gives ya the giggles.
I favor the 270 anyday of the week over a 7mm when it comes to putting game on the ground, every year I try to salavage meat off of critters that have been pounded by 7mm's that couldn't get it done in one shot. It's my very biased opinion but there is something that isn't quite right with the 7mm when you look at terminal performance vs a 270 cal.
I've seen many deer shot with a 7mm mag and they never ran, I've not owned one myself, the 25-06 seems to knock deer down at long range 1st shot almost every-time.
The 7mm mag is an old cartridge, and back in the day when people used FMJ bullets on deer it would not surprise me deer would run off.
comparing a 7mm with fmj ammo and bad shooting to a 270 wsm with ballistic tips isn't convincing.
the .277 have poor bullets for long range ballistics. I mean yes the Berger 150 has a .545 BC but out of a 270 it's going to have a rainbow trajectory.
the 7mm 168 VLD (617 bc) will be about as fast as a 150 from a 270..
the 277 Berger 140 vld has a worse (487) BC the a 7mm 140 VLD (510).. doesn't make sense, but the bigger bore same weight is better in this case.
and the 7mm WSM will most certainly shoot a 140 faster than a 140 in a .270 WSM as it is less overbore. a lose lose for the 270.
if we talk about the 6.5 WSM
. A 6.5 WSM with a 140 (BC of .618) grn VLD bullet and slightly more overbore, would be amybe 25-50 fps slower than the 270 WSM VLD 140 but would have an EXTREAME advantage at long range, by 100 yards the 6.5 WSM will be after than the 270 WSM
The 130 VLD with a .552 BC kills any the 277 has to offer, and would be like a laser beam (FLAT Shooting) I have heard of people getting140's to 3400 fps with 28 inch 6.5 WSM, so the 130 would be 3500 fps easy
If one knows his ballistics and drop to say 600 yards, all this doesn't matter anyway. but the 25 and 27 bores are the worst for high bc bullets.
I have a 25-06 and I know this all too well, the 108 JLK with a .500 bc is the best I can get. I shoot the .523-.466 BC 115 VLD's at a easy 3200 fps
But at long range the .243 .264 and .284 bullets are vastly better.
but if one wants to shoot at game out to 600-1000 yards, the .277 bore is one of the worst on the planet
the 6.5 WSM and 7mm WSM with it's much better bullets would be VASTLY superior to a 270 WSM at long range.
the story of your dad, or those 20,000 guys with 7mm mags that lost deer to a 7mm bullet are not going to cut the cake, the same 7mm guy will tell you of the 30,000 different deer shot by a 270 that ran away. Lets be realistic here.
let us not take extreme examples and blow them ouyt of proportion. I have seen Farmers take a .22 lr and kill deer 1st shoot drop in it's tracks, and I've seen a 12 gauge slug (72 caliber) go through a deers vitals and it run away for 1/2 mile . does this mean at 30 yards a .22 has more deer killing ability than a 3 inch magnum slug from a 12 gauge at 30 yards?