I am a BIG fan of the Area 419 Railchanger X with the Armageddon Gear Shmedium  mounted to it. I use it for a lot of stages. I started using it in rimfire and everything was great. When I used it for centerfire, I noticed that the rilfe would slide under recoil like a sled. I wasn't tightening the knob enough.  It seems I could not tighten it enough with my hand. Maybe my grip strength is weak.So I designed a wrench that would tighten it enough not to slide under recoil. I used it EVERY match. 
 
I showed it to some other guys who were also using that bag and plate and they asked that I make them available for sale. It is a simple thing, but it means so much if using that gear.