That would definitely work.
Here a couple more:
1. A technique that let's the marksman lower a foe's AC or wreck their armor. Maybe "Armor Breaker" or "Armor Piercing Bullet" or "Corrosive Round"
2. A technique that let's the marksman gain a bonus to attack/damage rolls against a single enemy once per encounter. Perhaps scaling with level? Maybe "Right in my Sights" or "Marked Target"
3. An light bullet that allows the enemy to be tracked/seen even in darkness/magical darkness. Probably "Tracer Round". Maybe also a variation that burns through concealing fogs, something like "Incendiary Bullet" etc.