The 143/6.5 bullet has a sectional density of .293. The 145/270 bullet has a sectional density of .270. That means that the 6.5 will penetrate deeper in any game animal at any range assuming equal bullet construction. And since we are comparing the ELD-X in both calibers that is as close as you can get to an apples to apples comparison. Both will penetrate more than enough on deer size game, but if you start hunting larger game the extra penetration is something to consider. A 140 gr 6.5 will match a 180 gr 30 caliber for penetration.
The 270 will shoot flatter at any hunting range. At some point well beyond where hunters will be shooting the 6.5 may be shooting flatter. Both shoot flat enough to hit game animals out to 500 yards. The 270 only has a 1.5" advantage at 300 yards with a 200 yard zero.
The 145/270 has a 270 fps advantage at the muzzle over the 143/6.5 according to Hornady (2970 vs 2700). But nobody kills stuff at the muzzle. The farther you go down range the more the gap closes. By the time you get to 500 yards the 270 only has about 120 fps advantage. Once you get out to around 700 yards the 6.5 will pass the 270. In other words the calibers are close enough (6.8mm vs 6.5mm), the bullet weights are about the same and impact speeds are more than enough at close range with either, and at longer ranges the same or a slight edge to the 6.5. No animal will ever know the difference.
But.....
I will almost guarantee that 9 times out of 10 a 6.5CM will be more accurate than a 270.
In an 8 lb rifle a 6.5 will recoil with about 14 ft lbs of recoil. Not much more than a 243. In an 8 lb rifle a 270 will recoil with about 19 ft lbs recoil. Just a hair less than a 30-06.
God post.
