That's a common Nikon Lens mount from around the 1960-70's era. They had large flanges that came right down over the lens mount, probably to shield it from rain and light leaks. When they went to the AIS mount in the last version of the F2 and F3 cameras, the meter coupler was on the lens mount flange instead of the little fork that was on the lens, so they had shrink it down. I don't know if you have a proper Nikon AIS adapter ring, or it's an off market brand, but it should completly replace the aperture ring and solve your problem. Nikon stopped making the adaptor kits years ago, so what a lot of camera shops do is mill down the extra bit of flange to fit. I had several of my old lens adapted to the AIS system back in the day, and it was both painless and fairly inexpensive.
David Buzzard's Technical Blog 
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