How do I desensitize a horse to gunfire for mounted shooting?

Desensitizing a horse to gunfire is the single most important and most time-consuming preparation task for mounted shooting, and it should never be rushed regardless of how quickly a rider wants to begin competitive runs. A horse that is genuinely comfortable with the sound and sensation of firearms being fired near its body is a safe, reliable mounted shooting partner. A horse that is tolerant under ideal conditions but reactive when pressure increases, when the shooting happens unexpectedly, or when competition excitement elevates the horse's baseline energy level is a safety risk to the rider, to nearby competitors, and to bystanders. The desensitization process begins on the ground, at a distance, and with the quietest possible version of the stimulus. Most experienced mounted shooting trainers begin with cap guns or other low-volume noise-making devices far from the horse, introducing the sound at whatever distance produces only mild interest rather than alarm. The same approach-and-retreat methodology that applies to any desensitization work governs this process — the stimulus is introduced at a level the horse can process without panic, held there until the horse relaxes completely, and then very gradually increased in intensity over multiple sessions. The progression from quiet noise-making devices to actual blank cartridges, and from ground work to mounted work, should happen only when each prior stage is completely confirmed. A horse that accepts quiet noise at a distance without concern is ready for the next step; a horse that is still reactive is not ready for louder stimuli regardless of how the training timeline feels to the rider. Rushing this progression is the single most common cause of serious mounted shooting accidents. Once the horse accepts gunfire while mounted and standing, introduce the sound while moving at a walk, then a trot, then a lope, and finally while making the course patterns the competition requires. The combination of speed, pattern work, and shooting is the full demand of the sport, and each component should be individually confirmed before the combination is attempted.