Yeah, it's a 50mm, but my low rings just barely clear the hand guard. I see that you are correct. While I can see through it just fine, (if I smash my fat cheek into the stock), I need to move it forward for prone and the eyepiece won't clear the receiver. I'm going to need a different stock eventually too. I like the angles on my other stock better. I need to take up hacky sack, the gun hobby is pricy.