I was browsing around for AR parts and ran across this:

http://battlecomp.com/index.php?main_page=page&id=5

NRA Instructors are included on their discount page.

Details:

To qualify for LE/MIL/PS/NRA discounts, please submit the respective credentials via email to This email address is being protected from spambots. You need JavaScript enabled to view it. or by fax to 650.403.4527. Please include a valid email and/or contact number if submitting documentation via fax. Once your credentials are received, we will contact you on how to proceed placing an order through our web store utilizing a discount.