These are genuine Savage factory replacement detachable magazine assemblies for the Savage 10 thru 16 and 110 thru 116 series.
Steel (with plastic follower)
Savage 110, 111, 114 and 116 (with factory installed detachable box magazine capability) in long action magnum calibers.
Factory Replacement Part
7mm Remington Magnum, 7x64mm Brenneke