Here is a list of Ruger KM-77RP MKII Rifles. It does not give a production #, but it does give a range of years that each model was made.

It shows the .280 as being produced in the known S/N range of 784-41255 to 787-86874. 1996 - 2000.

I would spend the $10 and get a letter from Ruger. It's a pretty generic letter. Tells the given S/N, configuration...KM-77 MKII, and month and year it shipped from the factory. If it confirms the 1992 date range it would be the earliest know .280 with the skeleton Zytel stock by about 4 years.

This info is from the "RED EAGLE NEWS EXCHANGE" RENE, all things Ruger. See the note at the bottom of this KM-77 section.

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Last edited by 308ld; 01/21/15.

Ed