I haven't been out rock shooting hardly at all yet but I plan to. I'll be taking pretty much the same loadout as below and maybe a bit more useless weight for training purposes.
Rifle (Equiped with sling & bipod), ammo, Badlands Superday, binos, wind meter, rangefinder, gps, headlamp, iphone, rear-bag, couple black garbage bags(handy things), spare socks, wool cap & gloves (even in summer, mountains get cold at night), fire kit, belt knife, spare folding knife, diamond stick sharpener, latex gloves, several peices of papre towel, TP (dont go in the bush without it!), 100yards of 130# braided fishing line (never needed it but seems useful), space blanket, bit of duct tape, 1.5 liters of water in the hydration bladder, 8x10 sil-nylon tarp and SNACKS! If I'm planning on being all day, I will have a bit more water and take my stove along to make some ramen or something similar for lunch.
I usually have extra clothing in the pack as well. If its not wet I typically still bring a rain jacket crammed in the pack.
Looking at that list it sounds like a lot, but all told I'm not very comfortable being off-trail with much less. I have run into some wacky weather changes and my 'extra' items probably only weigh 4 or 5 lbs.
The areas I hunt don't typically offer ranges much farther than 400 or I would probably pack a spotting scope & tripod as well.