@NuShootr, the timing of your post is propitious. I just finished
my first steps on the route last Sunday.
NRA has a separate instructor certification for each NRA course. In most case you must have passed the instructor led version, as opposed to the online or blended (part online/part instruct led) course, before you can take the instructor certification course.
Folks certified to train instructors are called NRA Training Counselors.
Start by looking at the NRA Training page at
https://www.nrainstructors.org
Use the information that page and the
search page to find for who is offering a Basic Pistol Instructor course at a location and timing that works for you. Contact that school or counselor directly to ask if your past course will count toward the instructor course pre-requisite. Explain to them you are missing the certificate, and ask if they can assist you in getting a new copy from NRA. You may have to shop a few counselors to find one who will accept your old course completion. Otherwise, take the current instructor led version and then the instructor class.
Next thing to know: Another pre-requisite to taking any instructor course is completion within the past two years of NRA's one-day Basic Instructor Training (BIT) course. This is a
how to teach the NRA way class, and does not involve any specific firearms. The trick is that some schools or counselors offer it as a separate class, while others incorporate it into the instructor course. That is, one school will offer a one day BIT class and a one day Basic Pistol Instructor course, while another school will offer only a two-day Basic Pistol Instructor class, which has both classes in the sequence.
The third part of passing the Basic Pistol Instructor course is putting at least 16 of 20 shots in a 6 inch group inside an 8 inch circular target (no bullseye) with
any caliber handgun at 15 yards. See
my other post and thread for the discussion. Practice enough before arriving for the instructor class so you have no difficulty with that range work. A counselor may or may not be flexible in allowing more than one attempt.
Finally, I took my courses, BIT and Basic Pistol Instructor, from
Level 1 FireArms Training. Owners David and Nicki Streb travel the country in an RV and pick-up with trailer, offering a wide range of NRA courses. In some cases you can take multiple classes in one week with their
Hell Week offerings.
Good luck!
Craig