Check out American Defense, Larue, or Bobro. All three have a return to zero guarantee. Most folks who have tested them agree that after taking off and remounting they will go back to within 1moa of original zero.
Having owned and used an ADM recon and Larue LT104, I can confirm those results.
Not sure if the PEPR will, I suspect that as long as you put it back on the same rail slot it will be pretty close.