You contact Remington customer service, and ask for an owner's manual for your rifle. Then read and follow the manual.
Which model??
how do you disassemble a model 49 ithaca 22 rifle
take bolt off
slide the spring to the 2nd hole and go from there
Action size.
You can read or download a manual at http://stevespages.com/pdf/remington_572.pdf or you can go to Remington.com and request one.
There is several you tube videos showing the procedure Aug 30, 2012.
Action size.
A Remington Model 700 chambered for the 7mm 08 cartridge would be a short action as the cartridge is based on the .308 Win.
marauder.homestead.com
Remington Model 12 barrels are threaded to the action. Barrels can be replaced with the proper equipment.
Model 58 is an automatic not a bolt action