Hopefully some of you will know what I'm trying to describe-seen one of these in a shooting clip once. Guy had a rifle with a metal buttplate which hinged upwards to approx. 90 degrees where it could then be placed on top of the shoulder to allow the rifle to sit in place while the trigger hand worked the bolt. I've been having problem recently with my .22 rimfire. When its raining-the stock likes to slip out of my shoulder when my waterproofs are wet. Anybody know what I'm talking about and where I could buy one of these 'hinged butt plates' or whatever they are correctly called? Thanks in advance to anyone who replies!!