During Boresight Verification, the A-Gunner installs the M154 on the dove tail mount.

During Boresight Verification, the A-Gunner installs the M154 on the dove tail mount.

• A. Side mount
• B. Base plate
• C. Breech
• D. Dove tail mount

Answer: (D)

During boresight verification, you need a stable, repeatable reference that sits exactly on the same axis as the gun’s bore to align the sight with the bore. The M154 is the reference device used for this process and is designed to attach to the dove tail mount on the A-Gunner’s cradle. That dove tail interface provides a precise, fixed position that sits in line with the bore axis, which is essential for accurate alignment. Mounting the device on a side mount, base plate, or breech would not place the reference in the correct axis or provide the same repeatable alignment, so those locations aren’t used.

During boresight verification, you need a stable, repeatable reference that sits exactly on the same axis as the gun’s bore to align the sight with the bore. The M154 is the reference device used for this process and is designed to attach to the dove tail mount on the A-Gunner’s cradle. That dove tail interface provides a precise, fixed position that sits in line with the bore axis, which is essential for accurate alignment. Mounting the device on a side mount, base plate, or breech would not place the reference in the correct axis or provide the same repeatable alignment, so those locations aren’t used.