At Wal-mart (or on-line), a Center-point 2-7x32mm. Water / fog / shock proof. Even has a lighted cross hair in red or green if you wish. I have 2. One on a 45-70, one on a 30.06. Long eye relief (won't give you a new and bloddy eye brow) and cheap about 70.00. It has taken all the rain, dropping, recoil I have been able to muster...and it yawns back at me. Nope, not perfect. A little foggy 'round the edges...But its mil-dotted, cheap,holds its zero, and its cheap.....J.M.H.O..your mileage may vary. (and No..I don't work / sell for them)
Center-Point Optics. Model # CP273RG, Adventure class. Comes with rings and a allen key to set rings
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