Shots hit consistently right of the target when using the ERCO sight in any variant, tested with SPAR-16, 16GL, 16S, have not tested with other 5.56mm weapons. It is Not slight and it does affect long range accuracy, even at 500 meters
Arziben also had this issue with the AK-12 and merged his ticket into mine. I also just tested with the TRG and Mk 20 (the other 5.56 weapons) and the same issue occurs, at least .25-.5m of consistent right dispersion at 500m
Since I assume the ERCO is meant for 5.56mm, I did not elect to test with other caliber weapons