ammo on the gun
For a hunting gun, I want no part of any ammo on board aside from what's in the magazine and chamber. These days I'm looking at how to make my guns lighter, not heavier, as I hoof it to and fro. I'm even carrying fewer arrows in my bow quiver!!!
For a HD/SD, patrol shotgun, ammo on board makes a bit more sense.
We had a run in my outfit on "sidesaddles" and everybody was quick to screw one on the side of their patrol shotgun. Then they realized that the gun often no longer fit in the rack in the vehicle. We also had some folks get carried away installing the bolts and tightening same, pinching receivers, stripping the mounting bolts. It was also a pain to dismount the whole side saddle to do a thorough cleaning of the trigger group, and if the bolts were stripped, you had to get creative to get the thing apart.
For me the sidesaddle lies right where I want to grip the gun in a casual, trail type carry. Your not always in a tac sling, or at a ready stance, you've got to carry the thing some distance, sometimes.
The elastic cuffs never hold up very long for me. The stuff gets loose, ammo drops out on the move, over bumps, I ended up going through elastic cuffs on a regular basis.
I ended up taking a stripped out sidesaddle and screwing the poly plastic fingers onto the Choate stock on my gun. Solid as a rock, and holds ammo great.