Ok so I decided that besides a sling about the only thing my new sgl21 needed was some night sights. I odered the meprolights and just installed them. The way that the blade notch sits so low, when you are on any setting lower rthan 300m you are actually looking down the middle of the groove cut in the sight arm. Nothing appears to be really bent or misaligned on either sight base ...I checked. But there is enough side to side play in the meprolight rear sight that in it's normal resting position that groove down the middle is not in alignment with the sight plain and you can see interference from it in the sight picture. If you apply a little pressure with your thumb to the right side of the blade the groove is in line with the sights and the picture clears up. Really want night sights but can't live like this. Hate to bend anything... seems like a small very thin nylon washer on the left front hinge pin might shim it over don't know. Any ideas?