Stick with the .270 for your re-barrel. A lot of people like the 6.5 manbun/creedmore, but out to 900 yards if your shooting a 150 grain bullet, it out performs the Needmore according to Ron Spomer. I also have a .270 and always shot a 130 to 140 grain bullet, but I should have been shooting a 150. BC is very close to the 143 eldx manbun. Anyways, here is a link:
.270 vs 6.5 Manbun(Creed)
For elk I came to the conclusion years ago I wanted more horsepower based on what I observed in killing them, and I decided to go to the .300 Win Mag and now the .300 PRC because it's better round in several aspects. Please don't derail the thread if you disagree this it's just one man's opinion. Any way I just never thought of going to the 150 back in the day. Now that I also need a re-barrel, I think I will stay with the .270, and I can load from 90 grain bullets all the way to 175 if I build it that way/proper twist. My stock, over the counter remington 700 ADL would clover leaf back when it was new in 1974 and it still shoots about moa to this day. I used to shoot rabbits, coyotes, as well as deer and elk. So, to the OP, don't get swayed by all the followers on the 6.5, the .270 is still as good as it needs to be. And if you reload like I do you already have all the stuff for the .270..