Years of experience has taught me to carry my ammunition in hard-sided plastic cases, such as the ones made by MTM Case-Gard. They’re a lot tougher than commercial paper cartridge boxes which have literally fallen apart on me more than once. I’ve got a few of these plastic boxes that have lasted decades. Right before the season, I always stick a spare box of ammunition in my truck. They may rattle around but the cartridges inside don’t get dented or otherwise damaged.
These days, I even carry factory ammo in such boxes when I head to camp and sometimes the box stays in the truck through the winter.
On one particular hunt, my brother and I were both using rifles chambered in .308 Winchester, a proven buck-buster that has put a fair amount of venison in my freezer. A couple of weeks before the opener, we zeroed both guns using my loads and they were X-ring accurate. He grabbed a few rounds from my box (he had his own ammunition but I think he does it to annoy me) before we headed across this canyon bottom and used them to anchor his prize.
As luck would have it, I had some spare rounds in one of those elastic carriers fitted to the rifle buttstock. On the way up the hill chasing Frank, I stopped to take a breather and noticed a couple of cartridges were gone. Well, you don’t drop cartridges out of a plastic box, so I made a note!.
Instead of taking any further chances with on-the-gun cartridge carriers, I think slipping one of the plastic boxes into my cargo pocket or backpack is a good idea. Problem solved.
There’s another reason I like these things. I can write on them with a Sharpie the exact load, including bullet weight and powder charge, so I know at a glance what I’m grabbing.