IIRC it was something that they offered with a rifle as an option for some extra money. I dont think they installed it on the rifle for you. We have seen 1 or 2 on savage rifles. Here are some of them on Mossberg .22s
http://www.rimfirecentral.com/forums/showthread.php?t=486253 
![[Linked Image]](http://media.photobucket.com/user/frankencat/media/misc/1557.jpg.html)
