You will still need to apply for authority to acquire, either as a variation or a 1 for 1 swap. Unless you have authority to acquire already on your ticket which you have not used. So when you do that........ask your FEO, or just tell them you need a WMR for long range work. If you have authority to aquire, try your luck as lon as your ammo says 22 rimfire, not 22LR, because if you are only allowed to possess 22lr ammo, you can not aquire WMR ammo.
If you see what I mean.