No, but I put my scope on my PSL with a large hammer and the locking bar is unnecessary as I doubt I will ever be able to remove the thing. Sounds like the dovetail in your rail or your mount is loose and at a minimum the mount needs to be moved forward until seated properly. Is there something obstructing it? or does it seem to get too tight to slide all the way forward.
If it is obstructed, you can try peening the dovetail by denting the edge with a metal punch but I'd save that for later with the hope of better info/advice.
I own firearms not to fight against my government, but to ensure I will not have to.