long action cartridges
You may find some loading have some air space in the case but others will fill every little space. The 270 is a wonderful and very efficent cartridge. The 30-06 case that the 270, 280, and 30-06 use does allow quite a big choice in which powder is used. A fast one will leave the case with alot of air space left in it. Most reloaders try to maintain a fill density of >90%. This makes the load more consistant as the powder can not shift around much. Remember that the bullet on most loads will seat into the case using up a large amount of the air space you see if you remove the bullet.
Karl