I noticed saturday my exps3-0 was sliding backwards, so i tightened it a couple more clicks. Then i noticed today that it still slides back by racking the charging handle. Its pretty tight as is. One more click and it barely contacts the rail when installing the optic onto the rail. I can still get it on but i can feel it. Another click and you cant take it off without loosening it 1 click. It doesnt move when jerking on the optic by hand and i do mount it all the way forward in the slot. I cant see anything wrong with the mount. the marks on the optic mount show that entire mount is touching the rail. The guy at eotech said just tighten it until it doesnt move but that kind of defeats the whole purpose of qd if i have to loosen the cross bolt nut to pull the optic off the rail.