A bullet (any bullet) can only be designed to perform "perfectly" within a very narrow "window" of velosity.
Corelokts are designed to perform best at 2500-2800 fps (like most cup-and-core bullets). This just happens to be the "window" of the .30-06 at 100-200 yards (the most common distance game is taken in North America). That's the distance the Corelokt built it's reputation.
Add more velosity (read....Magnum) and things get a bit "hinkey". If you want a real "test" of how "tough" a bullet is......try shooting heavy bone at 20 yards at a muzzle velosity of 3000+ fps. The Corelokt wasn't designed for this and will sometimes "fail" as will most bullets. Design a bullet for these conditions and then people will scream because they fail to expand properly at 200 yards (where velosity has fallen off).
The bullet makers can't win. The Corelokt performs great....in the "window" it was designed for. It does so at a moderate price too. To gain the do-it-all performancesome seek requires something like the Nosler Partition.....but it comes at a price.
You pays your money and takes your chances. Corelokts are a GREAT bullet.....as long as you don't ask them to do more than the design is intended for.
