OK I'll play devils advocate
now looking at this logically, to me anyway, the .270 has more power and is a larger cartridge in all ways and being a long (64mm/2 1/2") cartridge can utilise the slow powders to get the bullet of choice out to the target with authority and as it's also of slightly larger diameter should in theory at least have a larger surface to area to transmit it's payload of energy to said target. Although the .270 can work in a shorter barrel one is giving up some of it's potential :!:
Now the 6.5x55 Swedish cartridge seems more at home in a 20" barrel. The powders it likes are more medium burning in range and better, to my mind at least, in that shorter length it's just more suited plus the 6.5x55 is probably a better foxing round than the .270 Win.
Of course all this is just my take on it and I do happen to have a 20" barreled .270, no mod as it's a BSA CF2 Stutzen (Full stock), and on the other hand the 6.5x55 has I believe a 22" barrel that I threaded for a mod.
So me I would cut the 6.5x55
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