Well,
I will put in my real world 2 cent's, having owned probably a dozen and worked on many more.
Mini's are for the most part are not that accurate out of the box, especially the pre 580 series.
Older ones for the most part are 3-4 MOA. post 580's are around 2.5 MOA
This is with decent ammo.
On pre 580 series the Accustrut cuts groups by about 40% or so and usually eliminates flyers, if you take the time to tune it and not just bolt it on.
Post 580 series the Accustrut cuts groups by about 20% and usually eliminate flyers, if you tune it.
This is an average not a definitive.
Other things come into play as well, here is what I do to all mine before adding an Accustrut:
Bedding, either glass or shim bedding.
Polish trigger and add lighter trigger spring
Smaller gas bushing and properly space and torque gas block
Recoil buffers
Remove op rod hump
These mods are cheap and easy about $60
If the rifle still needs help I add an Accustrut, well I usually add it anyways, cause it just looks cool
Anyways, here is Eleanor and Sasha, this mornings range session.
This is the Norm, Sasha shoots under 1.5 MOA easily and Eleanor under 1 MOA easily.
Eleanor is a pre 580, Sasha is a 582 series.