You better start checking the vest of the top shooters in the country then. You will find a plastic tube with lead shot in the gun side seam
Some of us lower level shooters just carry a Barney mag or moon clip on that side.
Wow, I thought it would be an issue to. Here's the deal right from the rule book:
3. Concealment Garments.
All equipment should be so placed that, when wearing an open
concealment garment with your arms extended at your sides and
parallel to the ground, it can NOT been seen from the front, rear or
sides. Your concealment garment should be practical for your
environment and loose enough to allow easy movement.
Competition only garments are prohibited. Competition only
garments are defined as: vented or mesh vests that allow the
firearm, holster, spare ammo or ammo carriers to be visible when
standing normally, chest pockets, specially-made pockets or any
material inserted in pockets or around pockets to keep the pocket
open for stowage of partial magazines after a reload. Garments
that are considered “competition only” will incur an FTDR.
See “Proper Magazine Retention” in the Glossary for further
details.