Mount scope rail to barrel block or action on barrel blocked guns?

[maxpower]

I thought I had read somewhere previously that barrel blocked guns should have the scope rail cantilevered off the barrel block, not off the action. Is that right? What reasons are there that barrel blocked guns should have the scope rail mounted off the block, not the action?
This will be for a 300 WSM braked light gun, not a small 6 PPC with little rifle movement.

 

[spclark]

Doing such may make for less stress transmitted to your optics but I'll admit I've never heard this particular theory expressed before.

The mechanics would indicate a more 'stable' base mounting off the block if the action AND barrel are both 'free-floated', right? Mounting the rail & optics on the action adds mass at one end of the combination that may affect both optics and vibration state of action + barrel to some degree.

I have an aluminum stock from Mike Ross that features a barrel block. No provision for mounting sights on that block, nor recommendations from him when I bought it along with one of his actions ten years ago.

One time shooting Palma I noticed my windage was changing quite a bit with every round fired. Eventually I became aware that the action was unscrewing a little every time I opened the bolt! That's something you won't see with a block-mounted sight!

Bought a torque wrench the very next day....

 

[Gadget]

Hi
I have a barrel block gun and my scopes are mounted on the actions with no problems.
1 x 22BR Sightron 10 x 50
1 x .243AI NF 12 x 42
1 x 7mm SAUM March 10 x 60
All actions are Barnard P's and it takes 5 minutes to change out and then the gun feels the same every caliber, its a nice way to go, one stock that fits you and feels right.
I am a right handed shooter but I have all my rigs made LEFT action, this way I stay on the gun and my left hand dose the load and un loading, very efficient when you get the hang of it.

Gadget

 

[maxpower]

I hadn't thought about the optics being isolated from the vibrations of the action, maybe that could have been a reason why it was recommended?
Gadget. I have switched barrels in some other guns, but will likely not bother switching with this one (unless the barrel turns out to be a bummer)