I see a lot of guys putting flip ups on a flimsy handguard. Then some may say, "these damn sights aren't worth a chidt". When in actuality it is the flex in the handguard resting on the bi-pod or bags that is causing a POI shift. Even a tight sling hold can throw your POI off if you are using a cheap azzed handguard that flexes too much. That's on you, not your sights.