There is a thread just like this one on Rimfire Central and the conclusion was that absolutely NONE of the major fastener suppliers (Bolt Depot, McMaster, Grainger, Fastenal, etc.) carry #12-32 bolts in any length, material or head type. None. DIP does sell them in 1" length and Savage sells their 0.9" long OEM screws but nothing else is commercially available. If you want something else it's going to be a DIY project. There are #12-32 taps and dies available or a use lathe to make them from scratch.