I have two Model 70 featherweights c1985 vintage in .243 and 7x57. Like any other lightweight rifle the barrel heats up after a few shots. (By the way the .270 cartridge has its roots in the 7x57 mauser as you probably know)
But before thinking about changing barrels on your 270 try a little work on your rifle. My 7x57 used to shoot 1.5" 4-shot groups at 100 yards. Perfectly accurate for hunting out to 300 yards and just about everything I pointed it at fell over.
But I wanted to see if I could improve on this so I
- Fully floated the barrel
- Bedded the action
- Fitted a Timney trigger and set it to 2.25 lb
- Had the barrel recrowned - it had taken a few hits over the years
- Fitted a Zeiss scope
- Fitted a limbsaver recoil pad not because of the recoil but to lengthen the stock for a better fit
and I refined my reloads and improved my target shooting techniques. I now shoot sub MOA with this rifle which I think is not bad for a rifle of this age. Of the actions listed above those which probably had the greatest effect on improving my accuracy with this rifle were improving my technique, lightening the trigger and the recrowning but they all contributed.
As for reloads, once I had established a base load I found that that the rifle was quite sensitive to bullet seating depth. The 139gr Hornady SSTs in this rifle actually liked being seated 1.8mm (70 thou) off lands.
So what I am suggesting is that there are many things you can do before changing a barrel. But the first thing I would do is have an experienced shooter fire your rifle to see if he or she can improve on your groups. And the second easy action would be to adjust the trigger if it is still at factory setting. The Model 70s factory trigger is good and easily adjusted but don't go below 2lbs.
If you are not reloading experiment with different factory rounds and bullet weights, but only change one thing at a time.
This is probably teaching you "how to suck eggs" but I thought it worth repeating before you go spending money on a new barrel.