What does "C2 SOT" mean?

I ride my bike through Cherry Creek State Park sometimes and have stopped by the range (while holding my ears because I didn't bring protection) to check it out and see what people are shooting. I have yet to shoot there. I wish there was a way to get my rifle there on my bike, but with that case rule they have it could be difficult. You can get into the park for free on foot on riding a bicycle. ;-)