Have been having problems with the consistancy of my P99. Once I get to the range my first shots have been off, upon correcting have nice groups (for me anyway). When cleaning it I decided to check the rear site and it was loose, so I got a screw driver to tighten it and it completely slide off! There is a hole under the site that a small "rod" fits into? The rod, or what ever keeps the rear site on, was missing from the factory. Anyone know the name of this and where I might pick one up? Also, what would you replace the stock sites with. Been practicing in low light and can not see nuttin. Thanks!