Can't speak for that specific gun, but for most pellet and BB guns, you're looking at about 75 shots. But they tend to release more CO2 with each shot to propel the heavier projectile.
My TF 11 will get me about 130 shots if I use semi only with a couple of seconds between shots. In auto burst fire, I get about 100 shots. If I use sustained auto, I'll bet about 80-90 shots. So with a single-shot pistol, I'm sure you should get at least 100 rounds per powerlet.