I think the premium bullets do make a difference in killing power or whatever one chooses to call it. I don't see them as a tool to make a marginal rifle a sufficient rifle. When it comes to rifles like the 270, it was a very adequate caliber which is made even better with the use of premium bullets. Bullet construction and sectional density are far more important to my choice of guns than caliber size. I would pick the 270 with a 160 grain bullet over a 300 Mag with a 100-110 grain bullet.