Steve Gash article in Shooting Times

[JASmith]

I hate to burst your bubble on this, but, the .270 Winchester has access to the complete array of Accubond, Ballistic Tips, Gameking, Interbond, SST, Scirocco, and TTSX bullets up to 150 grains where applicable. This means plenty of low drag selections. The .270 earned its reputation as a flat shooting long range hunting cartridge by being exactly that, a flat shooting long range hunting cartridge.

I love the Grendel because I'm fascinated by its ability to do so much with so little, but sir, it is no .270.

Low drag selections coming into the .277 stable? Yes.

The kicker is that the span of bullet weights for the 6.5 caliber is about the same as for the .277 lineup. That automatically means a larger sectional density for smaller diameter bullets of the same weight. Hence it will be difficult to find a .277 bullet with superior performance to a 6.5 caliber bullet in the same weight. With the range of bullet weights being roughly the same, we see the 6.5 caliber has the edge bullet for bullet.

This means that, when using cases of equal volume, e. g., 6.5-06, the 6.5 will give superior performance with that superiority increasing with range for similar bullet designs of the same weight.

Turning to the Grendel, load data is available for bullets ranging from 85 grains to 156 grains. As long as these bullets are going fast enough to reliably expand, they will perform as well on game as the same weight .277 bullet even when the larger bullet is going a few hundred fps faster. Further, the slower bullet can outperform the faster one when it is going so fast that the bullet fragments instead of simply expanding.

This behavior was established in tests referenced in the Ideal Bullet Weight papers. This means that the only difference is the range over which the two bullets are within their impact velocity envelopes and the trajectory. Bottom line, as long as both bullets are above the expansion threshold and below the fragmentation ceiling, there is essentially no difference in average permanent wound channel between .264 and .277 bullets.

Further, as stokesrj points out, the 270 tends to drive bullets of classic design a bit too fast for reliable performance in game. Yes, there are spectacular wounds, but these are too often on the surface but with not much penetration because the bullet blows up, or a lot of meat is ruined by multiple fragments and ripping because of the near-explosive encounter.

The Grendel does not have this problem.