I modified previous concept of shotgun ammo pouch a little and moved to more traditional design with horizontally oriented tray and vertically oriented shells. Prototype with vertical tray and horizontal shells was less protected from weather and dirt, than I prefer.
Now the outer pouch is solid box structure with foldable lid and velcro on frontal surface. Note: pouch fastener is not installed yet, and new pouch is NOT fastened with velcro (frontal side of lid and frontal wall of pouch are not sticked together) due to the noise discipline reasons.