My plan is to get a shorter screw from Accurate Mag, then test the DBM for function.

Outcomes:
A - They don't have a shorter screw.
.......A1. - I cut this one short and the DBM doesn't function so I return the unit and sell the rifle.
.......A2. - I return the unit and sell the rifle.
B - They send me the correct screw and the DBM doesn't function and I sell the rifle.
C - They send me the correct scew and it works and every model, actress, and porn star in the world all fall in love with me and I am elected president.

C seems least likely.