I have them on my XIX. They shot about 4" low at 7 yards. Either the elevation screw was somewhat stripped or something else was wrong because when I tried to elevate the rear sight the elevation adjustment screw just popped out after two shots. I ended up having to drill and tap the elevation threads to the next larger size to get them working properly. Drilling the larger hole caused the detent ball bearing on the rear sight to pop out. I just used blue loctite on the screw.