If you purchased body armor [or other personally procured protection equipment] for combat duty, the entire cost (including shipping) is tax deductible. You or your spouse must have purchased it; if other friends or relatives purchased it, there's no deduction.
To deduct the armor, you must itemize your deductions. The deduction goes as an itemized deduction on Schedule A, which attaches to your Federal Form 1040. Only the amount of the cost which is more than 2 percent of your Adjusted Gross Income (in most cases, this is yours "and, if married, your spouses" combined salaries and wages).
For example, suppose you spend $2,000 for body armor, and you are single with service wages of $30,000. Your deduction is $2,000 minus $600 (or 2 percent of $30,000) or $1,400.
Besides body armor, anything else you purchase which helps you perform your service job better is tax deductible. This includes any equipment, or articles of clothing which would not be suitable for general civilian wear.
Visit the IRS website to learn more about deducting "Employee Business Expenses."