I put a Vortex Strikefire red dot on mine. I needed the flexibility of switching the color of the dot to green. So the height above the barrel measures less than 1.4 inches; which is rather high compared to most red dot sights.
I zeroed in the pistol for 25 yards shooting the H&N Baracuda Match pellet of 21.14 grains. So at 11 yards is where the pellet crosses the line of sight. From about halfway between 11 and 25 yards, the pellet only rises 3/10 of an inch. At 30 yards, the pellet is only 6/10 inch low.
These targets were shot at 25 yards with 30 shots in each target.
At 50 yards, I have to aim the pistol about 6 inches high. These soup cans were perforated with ease from the bench at 50 yards.
These targets were shot at 10 yards. The upper target was shot with the first 20 rounds and the bottom target with the last 20 rounds on a single charge.
These two targets were shot at 50 feet (16.7 yards) with 40 shots on a single charge. For the left target, my point of aim was center of the rat's head. So you can see that the pellet, is indeed, impacting .3 inches high. I lowered my point of impact on the right target so that the bottom edge of the 4 MOA dot was aligned with the bottom of the rat's chin.