Originally Posted by Pthfndr
Are you going to be shooting known distance on a range or going out to the desert/blm land and setting out targets?
If the first:
Rifle setup / the gun
Range finder - not required If you plan to shoot anywhere but a kd range, you will need a rangefinder. Without precisely removing the variable of distance, you won't learn much.
Weather reader (actual name?) - Most common is a Kestrel, nice to have but not required If you plan on shooting in multiple locations with widely differing elevations and climates, you need one. You could get a 2000ft+ density altitude shift from morning to afternoon.
Shooting mat - nice to have but not required for tactical type match. Shooting a High Power type match it ads a comfort factor
Sand bags / rear rest etc. - bipod for the front, small light weight bag/sand sock for the rear (if you feel you MUST have a rear bag)
Spotting scope - Only needed for High Power type matches
Ballistics calculator - make a dope card. With all of the apps available for smart phones now, there's no reason not to have one.
Paper / pen
Backpack to hold it all in
OP-my differing answers in red. Otherwise good stuff. If you only plan to compete at Sac Valley, some of my recommendations are moot.