I remember finding stripper clips laying around on gun ranges and not having an idea where they came from and what they were for. Most of them were for bolt action rifles and probable surplus ammo. I see a lot of ammo that is sold in bulk like 9mm, 45acp, 8mm Mauser and 7.62×39 are sold in loose ammo cases. The loose ammo can be cheaper, but it is also a pain in the butt to load if you are going to do some serious range reporting. Loading up 3 or 4 magazines isn’t a pain, but try loading up 10 magazines and you’ll feel the difference in your fingers. The military usually issues ammo on stripper clips for this very reason.
Many of my reloaded rounds are on stripper clips because I really don’t like the idea of storing rifle ammunition in loose containers. All of those primers floating around that don’t have anything behind them bothers me. Maglula speed loaders are the best option for you if you do have ammo stored in loose ammo cans. Stripper clips are a better way to store them and for 5.56 ammo, you can find a military speed loader for only a few bucks. Expect your magazines to show some wear from these loaders, but serious shooters should consider having them.