I saw a guy in hunting camp with a .338 WM in his shell belt. He carries a .300 H&H. I told him about it and he had no idea how the .338 got into his belt.
I've always figured I saved that guy some expensive surgery, because I'm pretty sure that .338 would have chambered in his .300
And judging from the guy's history, he would have dropped the pin on that shell sooner or later in a barrage to drop some sort of critter.