That is a very interesting bolt, the German markings are the post 1938 style eagle with swazi. Shame the WaA inspector number was partially polished off otherwise we could narrow down who marked the rifle (or the bolt for that matter).
My guess is the bolt came off a 91.30 captured during the opening months of Barbarossa as that would have been the greatest influx of captured Soviet weapons for the German Wehrmacht.
Probably wrong but is it me or do I see "SS" style runes under both of the eagles left wings ? My eyes may be failing me so forgive me if I am wrong

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Shame you can't take these bolts, rifles...etc to a labratory to see if they can determine when the markings were applied based on exterior wearing.