The 6.5 x 55 is a pocket 270, mine will just touch 3000 fps with 120gr Speer SP's While my 270 I use to own would tough a little over 3150 fps with 130 gr Speer SP's You wold be hard pressed to tell the difference either load has on the deer sized game I shot with it. For heavier game just switch to a 120 gr barnes X for the 6.5 and either a Nosler Partition or Barnes X in 130 for the 270. nope 0.013 thousands of an inch dose not make much of a difference, only on paper and in forums like 24 hour Campfire. Both are good hunters cartridges. Thou the 270 has a bit of an edge here in the States due to availability of both rifles so chambered and ammo on the shelf in most Stores. Meaningless for gun looneys!!
Gemayel pretty much nailed it with this post. For years my long time hunting buddy has used a 6.5x55 while I used a 257 Roberts or a 270. To be frank on the deer sized game we shot any other 3 were more than adequate. I finally bought a 6.5x55 but sold it relatively quickly to Jwall as I quickly realized it didn't fill a nich I didn't already have covered. I will say in my limited time with it or in talking to my buddy we never quite got the speeds I see mentioned so often on the Internet but I can say the same about most chamberings such as the 7x57 just too conservative with the powder scoop I guess. But in my case since I already had a 270 with some history and i have come to appreciate the convenience of being able to buy a box of federal ammo for around $15 I decided I'm a 270 fan.
