Top Lever moves to right
 

Acquired a 3 frame VH12 a few weeks ago. I noticed that the top lever moves to the right and recovers back towards the center when fired. A strong, new top lever spring helps - the movement is faster now, the lever only moves slightly, and it recovers back to center. It has never broken open while firing. It's just that the lever moves while firing. To be honest, this is not something I have noticed before so I am not sure if this happens with other guns. Anyone ever notice this or have this issue? Any suggestions as to why the lever moves?

any movement of barrels to frame indicating off face?

could be subtle but my guess is it is off face some.

No. Locks up good and tight. Both wth and without Forend. Seems to be on face.

Refit bolt or install new.
A lot of times these sort of issues are caused by harmonics and how the bolt is contacting the bite. It is more common with rotory bolting systems such as Fox, Smith and NIDs.