Took my new LC9 out for the first time today. Immediate issues pretty much shutdown the shooting after two mags. First problem was that I wasn't even on paper at 7 yards. Shot a couple rounds at the bull and hit nothing. Decided to shoot low and then high to get on the target. I was 8" low. Side to side was good but vertical is the issue. Running between 4-8" low. Went to check on adjusting the rear sight and promptly turned the set screw out too far and dropped it on the ground. Lost it and found that there is no height adjustment on the sight. Got home and was looking the gun over and discovered that I had not put the takedown lever back in the up position after cleaning the gun before the range trip. Is that going to have an effect on the gun shooting low? Also, does anyone know what thread size for the rear sight set screw? I found the replacement at Midway but no spec.