Make sure you check length after necking down the -06 brass. Necking down always forces the case longer. The .270 is designed slightly longer than the -06 but make sure you check.
If I neck down or up and thus change the caliber from what the headstamp says, I color the base with red magic marker to warn of the change. .25-06, 270, .280, .30-06 and .35 Whelen are all formed from the same basic brass. changing from one to the other is pretty easy.
Recommended you aneal the brass to make it easier and extend the life of the necks.
You can also take .30-06 family brass and convert into 7 X 57 or 8 X 57 (Mauser) but you have to trim off about 6mm.