I'm volunteer w/ Fresno County Sheriff's Search and Rescue, 501c3 non-profit. Am I able to list mileage, hours, & gear I must purchase for myself as deductions?

[Opus 17]

Mostly no.

You can't deduct anything for the value of your time.

Can can deduct mileage you drive when providing service for the charity, there is a special charity rate (14 or 17 cents I think.)

You can list out-of-pocket expenses as if they were cash donations to the charity, however, you can't take a deduction for personal property you buy for yourself if it does not become property of the charity.  If you own your gear, you can't take a deduction for it -- you can't take a deduction for donating the use of your own property.  If the gear become property of the charity (such that they could discard it, sell it or assign it to someone else to wear) then you can take a deduction for it.