svt,
Mine is not that brand but is more or less the same design. Funny thing is I always felt mine held zero fine but I wasn't actually using the rifle very much. I've been carrying the rifle a lot more the past few months and suspect that single point of attachment isn't as secure as it feels (at least mine).
I have a "single screw" type mount on another rifle but it also has an integrated lip that also helps hold it in place. This type of mound does not.
That or my scope is dying! 
