Other than Heavy Metal you're not going to see people running much other than the AR15. A few guys will run a Mini or an AK or something, but pretty much anyone who wants to be competitive will have an AR.
Loose: Not fastened, restrained, or contained. Lose: To be unsuccessful in retaining possession of; mislay.
Agree with poster above. You mainly see AR's. Sometimes you'll see SCAR's, but generally from sponsered shoters since they are so expensive, and not any better than and quality AR.
Just did my first 3 gun event yesterday with an AK because that's all I have at the moment.
Thank you for the membership kind stranger NRA Member "You cannot invade mainland America. There would be a rifle behind every blade of grass." -Isoroku Yamamoto. Japanese Admiral