I installed the MGSL in my G35 and got some range time today, although I was limited to about 25 minutes. I shot 100 rounds of .40, so really the initial break in rounds. My groups were ok, 2-3" at first, then they began to shift right. I found the rear adjustible Glock sight on this G35 is loose (I purchased the gun used a couple of weeks ago), causing my groups to be inconsistent. This makes accuracy testing moot at this point. I experienced no change in operation with the addition of the MGSL, the Glock ran like a sewing machine. More testing after I get the sight replaced.