My CZ 550 is chambered in 500 Jeffrey. Mine feeds a combination of Woodleigh 535g softs, 570g TSXs and 570g banded solids absolutely fine from the magazine. It is a little quirky about the magazine spring, you have to make sure as you load the last cartridgie it springs up a bit. If you do that, all rounds feed flawlessly. Not sure if it's a slightly week Magazine springs, rough spot in the feeding or what, but I'm going to have my local gunsmith, Kevin Weaver, fix that this winter and put on a brighter flouresecnt red dot front sight. So feed problems are minimal considering it was a conversion from 375 H&H to 500 Jeffrey.

Chuck