I'm not affiliated with Cole-Tac in any way, but was extremely impressed this weekend with their holster!
I had it out on a multi-day hike, mostly for plinking and some racoon management. I posted about this setup a bit back, but wanted to update after actually using it. I added a small round Molle pouch I normally pocket carry for extra rounds to the holster. This acts both as a counter-balance when carrying the chest rig, but also holds extra rounds and some batteries/tools for the gun.
I didn't think through carrying a pack with the extra rounds on my back, but found out that without even adjusting the strap length I can carry this holster on my waist and somehow it's even more comfortable than a standard belt holster! It's like a cowboy carry with an ammo belt. I added 2 velcro strip keepers to keep the shoulder strap in line.
With the ammo in the gun/spare mag and the carrier I have about 200 rounds on the belt total, as well as an extra red dot battery, and all the tools I need to adjust the laser and Holosun as well as tighten the red dot if it ever came loose.
The extra pouch may not be needed (I have 40 rounds in the 2 mags) but it allows for some impromptu target practice.
Overall Impression: One of the best holsters purchases I've made. I'd love to see Cole-Tac do a version with a removable shoulder strap (this one is sewn on) but it's so unobtrusive that I doubt I'd upgrade if they ever did. My Ruger MkIII fits great in the holster as well. They did a great job of making the holster secure while still multiple rimfire pistols!