Some people they carry firearms on the trail. Professionals who teach self-defense say that the likelihood of you being able to successfully unholster your weapon, aim, and fire while dealing with a moving horse and someone is trying to unseat or threaten you is low. Their recommendation is to carry wasp spray in an arm band and use that instead. It fires a very directed spray up to 20 feet (unlike pepper spray which discharges a broad field and can drift into you and your horse) and is legal in all states. Practice using it by firing on helium balloons tied to a fence rail. Aim for the eyes. You can also spray back and forth if there is more than one threat, something else you cannot do with a handgun.
If you can attend a self-defense clinic, do so. Many of the techniques are covered in de-spooking clinics, which are also valuable for anyone who trail rides.
www.Mountedpolice.org Bill Ritchey is a retired mounted police officer who, among other things, trains horses that patrol Mardi Gras and has successfully competed in national mounted obstacle course competitions. His weekend-long, de-spooking clinics include training in self-defense on the trail.
Mike Hughes on YouTube: https://bit.ly/3kDTsb8
Demonstration by Eddie Rodriguez 2012 North American Trail Ride Conference. This is an online article with a video within the story. The audio is difficult to hear, but the video demonstration is good. https://bit.ly/3imeoRm
www.whoapodcast.com/self-defense-trail-riders/ (A podcast by John Harrer with advice and techniques.)
This video demonstrates some of the techniques taught at a self-defense clinic Harrer arranged. https://www.youtube.com/watch?v=l5Axsucdgp4