I too have an Air Arms S410 that was not indexing properly. I purchased a new magazine and the problem continued. I then changed out the index post and the original magazine worked as designed. However, the new magazine still does not fully index. It appears to require slightly more force to move from one cylinder to the next (stiffer). I am glad the gun is working well with the original mag, but I would like to be able to use the new one too. I've read past articles about taking apart the mag and clipping the spring. Any thoughts or suggestions would be appreciated.