My brother was using an ammo carrier several years ago while deer hunting and lost several very expensive rifle rounds because they had slid out of the holder without him realizing it. I found these ammo holders with flaps, bought them for all my brothers, my kids and myself. Have them on all my rifles and shotguns. Have performed flawlessly. As well as keeping the ammo in place the flap also hides the shiny brass casings of the extra rifle rounds and the colors of shotgun ammo. Only down point is when you open the flap they make a Velcro separating noise but that is easily lived with for the job they perform.
Pros: It has a flap, easy to install\remove
Cons: Velcro noise when separating flap
This review was written in the old system and had content requirements that are different than reviews written today.