Distortion is obviously a factor, but the original prop's scope was clearly also mounted at a slight angle to the main body of the gun.
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I think what Vanitas is saying is that on the HERO top view, it looks like the scope angles in toward center at the front end so it's not parallel to the body. If so that would mean Carl simply/likely used the same thickness spacers and due to the mag well taper the entire mount and scope angles in at the front.
Not conclusive by any means but...
Copied half the front spacer and overlaid on rear. If not the same thickness it's awfully close.
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Looks like a real time saver! Is there any risk of damaging the drill by applying even slight horizontal force on it? I don't want to introduce a wobble or anything in my two drills, I might have to pick up one from Harbor Freight to use for this. Also what'd you use to attach the scope to it?