Posted by John Liles on April 19, 2017, 4:28 pm, in reply to "Vent rib width"
Could it be that that is the original VR that someone has machined down? If so, that would sure be better than an aftermarket add-on. Not a VR expert by any means. A research letter would verify whether the gun originally came with a VR, and if so its likely that that is the original yet modified rib.