TexasCHLforum.com

To qualify from exemption from the firearms proficiency, you must within the five years preceding the date of your application have completed a course of training in handgun proficiency or familiarization as part of your service with the armed forces.

If you meet that I guess you could take a course in SC

The problem would be getting an instructor to SC.

I imagine you will need to come to Texas to get certified.

Edit to add; Thank you for your service, Marine.