Loops are snug, as good as anything commercially made that I’ve ever had. If I would do anything more to this design it would be to sew a flap, at the bottom, that would come up over the whole thing and attach at the top with velcro (noisy) or a sewn in magnet maybe. When undone it would fall down and you have access. Ammo would be protected from elements or from falling out. Kind of like a foward opening flap on a chest rig.
As for loop integrity, I don’t leave ammo in them, when hunting is over I remove it. That way it doesn’t get stretched out permanently. It’ll last a long time.
This is intended to be a little minimalist, I don’t like the zip pouches and stuff like that I see people using on their stocks. To bulky.