Somehow, for the sawed-off shotgun, you seem to need rank 10 in both pilot AND tanker.
Community Admin@Nixkill666 Thanks for the post, you're not the first to report some oddities with progression/unlocks.
Can you try grabbing the shotgun unlock within a match itself. I think this will invove waiting for a plane to be available, then going to Customize, but hopefully this will let you make the purchase in question.
Somehow, for the sawed-off shotgun, you seem to need rank 10 in both pilot AND tanker.
mwaldier is right - to get the sawed-off shotgun, you need 10 service stars both as pilot and tanker. Until then, the only opportunity to use sawed-off shotgun is picking up the Tank Hunter kit (sawed-off shotgun is the secondary weapon in it).
Also, there is no progress between 10th and 11th service stars, because there is no 11th service star - their number ends at 10.
