Hey all, I've been into rc for aboot 8 years but Just recently got into heli's (its "the thing" at my lhs so what the heck...

) but I have a slight issue;
My blade MSR is not hovering too well, when I get it into what
should be a solid hover, it starts swirling around on me (not pirouetteing, the canopy keeps its orientation but the heli swoops around like its being flushed down the toilet) Now I have completely rebuilt the thing, main shaft isnt bent, swash seems to be fine, frame is ok.... I'm no heli expert so I'm at a loss here, any help guys?
Cenzo