Around 50 different calibers, anything from a .17 Rem to a 458 Winchester mag.
Caliber is .243, buy ammo in .243.
The Remington 700 and its ammo is likely sold at where other guns are sold. For online stores, you can try Guns International, Gun Broker, or Buds Gun Shop.
Any scope that you choose to use can be used on your remington model 700.
Remington .270, 150 grain.
There is no long action 308, it's a 30-06.
.308
The R-15 uses SAAMI .223 Remington chambers and is not recommended for use with 5.56 ammo. Stick with commercial .223 and you'll be fine.
223 Remington.
Winchester made some that did. Remington also, IIRC.
Depends on what you mean. UMC is a brand of ammo made by Remington. UMC = Union Metallic Cartridge By Remington
Yes, Remington makes the 700 in that caliber.
.22 WRF or .22 Remington Special