"Whatever can go wrong, will go wrong". Lol.....
Note to other hunters out there: The elastic loops in a stock pack can suddenly lose their tension after 7-8 seasons, especially with a heavy round like a Whelen. I was hiking in on opening morning this Saturday when I heard a metallic "clink" noise behind me. There was nothing in my backpack that should have made that noise, so I stopped to check it out. It was the last couple rounds that had fallen out of the shell loops on my shell holder (rifle slung on my back). I made it to my stand with 2 cartridges after some flashlight searching.
Found a few more on the hike out. So.....replace those $15 ammo carriers every couple years for cheap insurance. And it's probably a good idea to pull the rounds out during the offseason.
You can maybe get away with having tired elastic in your worn-out socks and old busted underwear, but you aren't trusting them to hold your ammo.