That trap looks like Those MB750s my brother sets for coyote. He claims they are STOUT! Now I believe it.
That trap is too small for a 750. I use alot of em and the one on the lions foot is likely something around the size of a 550. I trapped a good size lion last week in a 750 that had killed a calf, but I prefer a new house 114 because it has taller jaws, for a higher catch. Lion feet are softer than say a wolf, or coyote foot, more pliable if you will. Because of that lions can, and do pull out of traps with a marginal catch. I have had a couple of lions pull out of 750s over the years. The guy in the photo was extreme!y lucky that he held the lion, and got his trap. I am glad he got him. And yes lions do leave a neck of a trap circle.
