Eotech exps3-0 sliding backwards

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.

You shouldn't be tightening it with it clamped and locked on the rail. Tighten it until the rail starts to grab when you are trying to lock it, unlock it, tighten one more turn, and try and clamp it on it again. You should repeat this process until you get a good clamp on the rail and you can't take it off with your fingers. At this point, unlock the QD mount, loosen by one click, and it should be tight enough to clamp down on the rail but loose enough where you can get it off quickly if you need to.

Im not adjusting it with the lever closed. And ive tried that exact method without success

What brand rail/upper are you using? Sounds like something has to be out of spec. Has this always been an issue or has it just started even though you've used the setup for a while?


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Bcm upper, geissele rail, but the eotech only sits on the upper. Its a completely new set up and gun