Well, lets dispense with the BS part of your problem. A shady factory or importer can do a few things to shoot a good group and make your life a misery- after all, you are merely the inconvenient customer.
1. Take the rifle out of the stock, set the action in a test jig and shoot a tight group.
2. Simply shoot the rifle at short range.
3. Use an underpowered ammo that is sure to produce lower harmonic vibrations.
4. Make efforts to erode the customer's self confidence by introducing shooter ability accusations.
5. Tell customers that a rifle need only be minute of deer but not ever explain what minute of deer means.
6. When all else fails- Have a temper tantrum at people like me during a trade show at around 6am before the punters arrive- for helping shooters understand the difference between rifle problems versus human error.
Now, about that Finnlight.
I was kind of lucky, I had both a normal contour M85 and a Finnlight on the bench at the same time, a chance to observe both.
Historically, there have been a lot of complaints about the Finnlight. The rifle I had on my bench, shot exactly the same as yours. The wood stainless (heavier version), seemed to shoot around 1-1.5 MOA but the owner wanted it bedded to avoid any future problems with moisture/ warping etc. I think it was the right thing to do.
I bedded both rifles and learned a lot from the excersize.
You are dead right about the lug set up, with regard to the new magazine release system and its negative effect on the bedding surface. The extra metal has the potential to cause great problems. If the bedding is pinching in this area, even minutely, groups will open up. So, the first thing is to make sure that the bedding is as correct.
When checking the bedding over(am talking about after epoxy resin bedding), start at the tang and check firstly for relief at the rearmost of the tang. After this, observe the actual stock fit along the sides of the action back to the tang, warpages within the plastic mold, tight areas. The Sako is made to "look aesthetically pleasing" so the stock to metal is often too tight. If you find pinching, relieve it.
Next, check the fit of the bedding around the recoil lug area. This rifle is difficult to bed in that the action sidewalls are parallel with no taper. Parralel metal has the potential to pinch. One has to be very careful to avoid either too tight a fit, or too loose a fit. The old favorite Kiwi clear boot polish (instant wax shine) is no good as a release agent for the Modern Sako rifles. Not that it matters, Kiwi have discontinued making this product. The latex release agents and tougher polymer release agents are much better. I use/ supply a polymer.
OK, here is a terrible pic. I have used the Howa M1500 action and doctored the pic a little, to make it look like the Sako- albeit in the roughest manner.
The added green rectangle is the problematic bottom material/ magazine release we have been chatting about. The color green denotes that I would prefer to use masking tape to relieve this area. All the masked areas are correct. Any area not masked, should be relieved with a thick release agent.
If you have a rifle that has been bedded by another person and is pinching throught the sidewalls of the action, scraping or sanding won't work. The epoxy resin needs to be bead blasted to obtain a better fit. Either this or start again. I learnt this by doing an incorrect job on a Sako (not enough relief). I used blasting as means of relief and testing- was able to watch groups shrink down.
The barrel on the Finnlight is a potential problem. On the two rifles I had side by side, once bedded properly, the heavier barrel jobby shot .9 with Federal factory ammo, better with handloads. The Finnlight seemed to shoot no tighter than 2.5MOA, pretty much where I had started from (was starting to sweat).
After a lot of experimenting/ double checking/crying to wife- I discovered that the Finnlight barrel shot very tight groups as long as the barrel was cool. By cool, I mean cold shot cool. I could shoot between .8 and .9 as long as I shot the group over 3 minutes. The barrel was the only difference between the two rifles, the bedding was the same, checked over- dye tested for contact etc. It is my conclusion (after seeing further complaints), that Sako are not yet capable of creating an ultra light weight barrel capable of sub MOA groups when three shots are fired within less than a minute.
When things get to this stage, you have to make some bigger decisions- Rebarrel, adopt a muzzle brake perhaps. Auprressor is out becuase of the fluting. There is a lot to think about, even the simple question of whether you still like the rifle after what it has put you through.
European engineering has been suffering from a few problems of this nature over the last few years. Some of the designers/ draughtsmen, try to out do each other with regard to 'innovation'. Square toe high polished leather shoes, fine coffee, a knowledge of fine wines and silly terms such as woody, nutty with hints of chocolate. Designer glasses, morning meetings, collectable coupe vehicles- these are the tools of some of our great thinkers in the gun design world.
Few people seem to understand that the term innovative, in modern engineering, should reflect simplicity, efficiency and effect.