Ok, I've got an Aimpoint Comp m3 and the QRP mount.  I've currently got it at the back of the railed forend and not the flat top of the receiver.  That just seemed to be the easiest for me to see the dot with.  I've got a stubby RRA stock (we're not allowed collapsible stocks here -- you could kill someone with those).

I have not shot the rifle yet with the M3 attached.

Now given that I will be adding iron sights and plan to add the 3x scope and SAMSON mount down the road, where SHOULD I put the M3?  

I keep my aimpoint on the Flattop aligned close the rail, I believe Stickman mentioned that the optic could shift on a railed hand guard.

That's a good point.  Will the 3x magnifier and BUIS all fit on the flattop though?

Quoted: That's a good point.  Will the 3x magnifier and BUIS all fit on the flattop though?

The photos found HERE show a BUIS, 3X magnifier, and Aimpoint M3 in an ARMS #22M68 cantilever -- all mounted on the upper receiver's rail.

Quoted: Quoted: That's a good point.  Will the 3x magnifier and BUIS all fit on the flattop though? The photos found HERE show a BUIS, 3X magnifier, and Aimpoint M3 in an ARMS #22M68 cantilever -- all mounted on the upper receiver's rail.

Yeah, but they're not using a QRP mount

You can always put it in a box and ship it to me...