MPA Matrix
Milling out the forward lower area to make room for the Flat Mount ABR. Milling holes for dowel and stud clearance and adding new mounting holes in the stock.
The Rules for adding an ABR
Do not raise the rear stock more than absolutely necessary
Space behind the grip to the front of the ABR minimum is 2.25” so the adjustment hand is not hit during recoil
ABR parallel with the bore