I would go for the Vangaurd S2 over the savage. its holds 5+1 and its cheaper too. The s2 have a heaps better finish than the old ones.
From what I have read over bore calibers like longer barrels to get the most FPS. Normal cals like the 223-308 ect don't really suffer from shorter barres as much
An over bore cal is something that has been necked down from a parent case. 22-250 243 25-06 270 belted magnums also fit into this category.
I'm not talking about accuracy but energy and fps left when down range. Some very popular righters have say over the years that less than 24" robs the 270 of its full potential.
Here is a link to an interesting barrel length test. not 270 but though someone might get some interest from it.
http://www.tacticaloperations.com/SWATbarrel/