Depends on the model, I have a Savage 110 270 and it hold for 4 rounds.
Uses .277 bullets
I just picked up 90% Savage 110E .270 with 3X9X40 for $350.
Just picked up a savage .270 WIN. in a model 116 with bull barrel. From Shiptons Big R in Billings,Montana.PH:406-652-9118.
It can only safely accept the 270 Weatherby Magnum if that is what it is chambered for. If you want to chamber it in some other caliber than get a new rifle. Just because two bullets have the same diameter bullet (270 or any other caliber) does not make it safe to fire it in your gun.
Medium
try http://stevespages.com/page7b.htm
in excellent condition, i have seen them go for $270
have shot targets with 270 Winchester at 1000 yards. never tried one further. Have shot smaller bullets at longer range, would think the 270 would be accurate at longer range as well.
20-400 USD or so
In my opinion theyre fairly close to each other. Theyre both based on the 30-06 cartridge case. The 270 shoots lighter bullets at higher velocities but the 308 can shoot heavier bullets. I would base a choice depending on the application.
3+1 Meaning 3 in the magazine and 1 in the chamber.
About $300, depending on exact version and condition. Really good rifle, BTW.