Ruger 10/22 receiver mount fixed rear aperture peep sight

A poor-man’s Tech Sights, if you will.  It mounts to the rear-most two receiver holes, which are threaded 6-48.  Ruger’s 10/22 receiver hole spacing (for the rear 2 holes) is 0.860” center to center.  I can flip the barrel-mounted sight down and out of the way.

I used ABS for durability & heat resistance, but I doubt the receiver gets super hot.  I’m sure any material you choose will work fine.  I got better results using a 0.12 mm layer height, but it looks fine with 0.2 mm as well.

I made this to take to an Appleseed event, to line up with the factory front sight.  The model has a 1.5mm aperture (0.059”), but if you need more light, you can drill it out a little more.  Printed, my aperture came out to just under a 1/16" drill bit.  So I cleaned with a 1/16" bit (0.025").  I will drill more if I need more.  It could even be drilled and tapped for screw-in aperture inserts if a person wanted.

Test on paper to verify whether your rifle does the same.  It is not field-adjustable.  Place shims under it to raise higher if your rifle shoots low.  If it shoots too high, you can sand the bottom down.  You’ll need to drift the front sight for windage.  Move the front sight left if it shoots too far left, and vice-versa for right— right?