Hi @mattie3 ,
Thank you for your service, you may be able to deduct the mileage by filling out form 2106 Employee business expenses. I an attaching the IRS guide for this, scroll down to the section labeled, "How to report my reserve related travel expenses". This will give you the guidance on how you can claim the extra mileage.
https://www.irs.gov/publications/p3#en_US_2021_publink100049678
All the best!
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