Curious if anyone else has ever experienced this. I mounted an Airmax 6-24×50 That had been on my TX for about 5 months. Won a couple matches with it. I took it off about 4 months ago because I wanted a dot reticle so I replaced it with a Sightron STac. I pulled the Airmax out of the gun safe and mounted it on my recently purchased LGU. I found the parallax knob almost impossible to move and it would not adjust. Now 2 days later I was putting it in the box to return and much to my surprise I found the parallel knob moves freely and works as designed. Crazy.