Poor bedding on Sako 75

[co17]

I have a problem with my .308 Sako 75 Deluxe.
When both action/stock screws are tight it shoots 1.5MOA groups but if I loosen or completely remove the aft screw the groups shrinks to .75MOA.
I found out accidentally as the screw comes loose after 50 shots no matter how tight.
What do I do?

 

[EddieHarren]

Have it bedded.

 

[co17]

Have it bedded.

That is the obvious answer, but Sako rifles usually shoots sub MOA right out of the box with the right ammo.
Why doesn't this one?

 

[EddieHarren]

It needs to be bedded.

 

[royinidaho]

Ya just gotta love this place.

 

[James Jones]

Yep , sounds like a good cantidate for a piller bedding job , what may nbe happening is that the recoil lug is bottoming out in the stock before the bottom of the action makes good contact and when the rear screw is tightened then its stressing then action (doesen't take much) , once the gun is properly lipper/glass bedded then the action will be making full , even contact without stress anywhere.


Have you called Sako and explained the trouble?

 

[AlbertaAl]

Regarding pillar bedding...I often frown on this practice when dealing with walnut stocks.
The act of pillar bedding requires drilling out the factory holes to twice or more the size to accomodate the aluminum pillars. These drilled out holes reduce the integrity of the walnut stock and if the stock was going to splinter ...this is where it will happen...you are dealing with wood and wood grains.
Laminate or synthetic stocks are more ideal candidates for pillar bedding.

Just my opinion since this occured to me.