Ah, cherry picking.

Quote Originally Posted by BobinNC View Post
Sierra .224 77 Gr Match King G1 BC .362

In 5.56mm

Started @ 2650 FPS (16" barrel) with a 50 yd zero

@200 Yds -1.1" low (0.2 Mils) 833 Ft lbs of energy
@300 Yds -10.6" low (1.0 Mils) 686 FT lbs of energy

Barnes .308 120 Grain TAC-TX BT G1 BC .358

In a 16" 300 Blackout

Started @ 2200 FPS with a 30 yard Zero (to optimize drops for the slower projectile)

@200 Yds -0.3" Low (0.0 Mils) 902 Ft lbs of energy
@300 Yds -14.8" Low (1.4 Mils) 717 Ft lbs of energy

I don't know what your looking at but the 300 Blackout appears to be superior to the 5.56mm at all ranges under 300 yds.

For engagements over 300 yds you better have a good scope on the superior 5.56mm and know how to use it at range, because you going to need it.

It seems to me that the 5.56mm is sort of a niche option, and compares to the 7.62x35mm, not in a good way. But for engagements over 300 yds it is better, but only with a properly scoped rifle.

IMHO and YMMV.....
Factory velocity of the Barnes load is 2150fps, not 2200.
http://www.barnesbullets.com/ammunition/vor-tx-rifle/

2650fps is very slow for a 77gr bullet in a 16" barrel. Mk262 and the Black Hills offering were based on 2750fps for that bullet in a 16" barrel.

Using different zero distances is not a good comparison. I'm using total drops below rather than path estimates. Drop does not vary with zero distance or sight height. With either cartridge you can pick various zeros or just zero at 100 and dial on the scope.

Here's how it looks to me. These are run from the same ballistic calculator using the same pressure and height above sea level (630ft) for true apples:apples comparison.

Barnes 300BLK
__________Distance / velocity / energy / drop
Muzzle _____0 _____2150 _____1232 _____0.00
300yards _____300 _____1527 _____621 _____42.63

Black Hills factory ammo with Sierra 77gr TMK (.415 G1 BC)
__________Distance / velocity / energy / drop
Muzzle _____0 _____2750 _____1293 _____0.00
300yards _____300 _____2118 _____767 _____24.66

Hornady ELD Match, standard pressure, 73gr ELD (.398 G1 BC)
__________Distance / velocity / energy / drop
Muzzle _____0 _____2700 _____1182 _____0.00
300yards _____300 _____2050 _____681 _____25.83


Wind drift will be even worse, in comparison, than drop. Using shorter barrels will reduce the differences in velocity, energy, drop and drift, while using longer barrels will increase the benefit of 5.56. With really short barrels the 5.56 will lose relatively more of its velocity and energy, so 300BLK will be noticeably better for energy, but will not catch up for drop and drift until barrels are down in the 6" range, which is shorter than practical for either cartridge.