Yes
General information on the 721 can be found on the Remington website here: http://www.remington.com/library/history/firearm_models/centerfire/model_721.asp
Your Remington model 721 was produced from 1948-1962. If you can supply the 2,or 3 letter code on the barrel we can pinpoint the month and year of production.
see below
yes
You have a browning a-bolt rifle chambered in .270 winchester caliber.
What model of rifle are we talking about?I would need to know along with the age of the rifle to give you a accurate value.
Long action.
50-500 USD depending on specifics
Depends on your pocketbook.
Winchester lists the ballistics of the ammunition it sells.
100-1000 USD depending on specifics.
Yes. The .270 is simply a necked down .30-06 cartridge, and thus the action would be the same as the .30-06.