[WTB Nova Barrel]

Im really looking for an 18.5 inch or something similar for my Nova. I would also be interested in a 26 or 28" barrel in max4 at a good price. Anyone have one or know where I could get one? 

[H&K sbe ejector screw size]

Does anyone know what size the two Allen head screws are on the ejector plate? I believe the screws are #29 on the sbe schematic 

[Changing ejector plate on H&K SBE]

Can anyone tell me what size the two ejector screws are? Metric I’m assuming?