Depending on the competition for the gear. If you are talking High Power and Long Range...
Rifle, ear protection, eye protection, ammo, mags, and something to see your spotters and scoring disks, binoculars will work.
Then to be more comfortable (but not mandatory) a mat of some kind to lay on.
Shoot a couple matches to see if you want to continue, then you will probably want a spotting scope and stand, shooting jacket, stool, and a bunch of other stuff that you will accumulate.
Just about any rifle will work if it has a detachable mag that holds five rounds for the rapids, so just take what you shoot best with iron sights and shoot.
For the long range they have F-class which you can use a bi-pod or rest and you can use a scope, and the any rifle/any sights class.
I shot a 2X600 today using an AR15 in the service class.