The only "problem" with the Corelokt is that they are designed to perform best at "standard" velosity of 2500-2900 fps. Magnum rifles can get out of the comfort window easily at close range.
When I was younger and did not reload, I used 150 grain Corelokts exclusively in my .30-06. Performance and penetration was great. Then I took up reloading.
I was young and dumb and sort of "pushed" things a bit (actually pushed things a LOT). I'll not list the loads (out of fear that my computor would explode), but I was pushing 150 grain bullets out the muzzle at 3100+ fps in a .30-06. That's when the "problem" with Corelokts appeared.
Most of my shots were at under 100 yards and suddenly the bullets were failing to hold together and penetrate like I was used to. Instead of backing off on my loads (like I should have), I went to a heavier 165 grain bullet and everything settled down.
It wasn't the heavier bullet that did the trick, but rather that I could "only" push them to about 3000 fps as opposed to the 3100+ with the lighter slug. This put the Corelokt right in the "sweet spot" as far as velosity is concerned at 100 yards or so. This is true of most cup-and-core bullets. They simply weren't designed to perform best at 3000+ fps striking velosities.
I have since gained a bit of experience and knowlege and now load those 165 grain bullets to a more "reasonable" 2900 fps and couldn't ask for better performance except against the heaviest of game. Nothing "wrong" with the Corelokt......just miss used by some with Magnum rifles.
