You need to have a firm plan on what you want to do down the road. If it is going to be a 6.5 CM (and stay that) then use a short action. Depending on what 7mm cartridge you would use- you may want a LA. Especially if you are handloading and loading heavies. I have a 260rem on a short action and one on a long action. The throats were cut accordingly- the SA I load at 2.8 and the long action I am 3.035, and they both work great. So just make sure you have a plan on what you want to do with it- and what ammo you want to shoot.

If you are going with the Savage action then make sure you can find all the other parts (stock, chassis, bottom metat, dbm, etc) before you start. Not as many options for a savage- but if they have the combination you want then it should serve you good.