necessary to resize pulled m855 and 7.62 bullets?

[Falstaff]

im looking at pat's and he sells bullet resizing dies as well as all the pulled military bullets and surplus powder. Is it mandatory to resize a pulled bullet?

[joelogic]

Sometimes with machine pulled but not with air pulled. Usually the description will say "Resized" or "Needs resizing".

[gunboat]

what is the proceedure for "air pulled" ??