Here are some upgrades for the MBAR which should make it sturdier and more accurate.
More Instructables by me.
Step 1: Barrel Strengthening
Follow the images. Should be easy. No explanation should be necessary.
Step 2: Handle and Sight: Constructing the Components
Images 1-3: Make 1 each.
Images 4-5: Make 2 each.
Step 3: Handle and Sight: Construction
Follow the images:
Image 1: Add gray connectors.
Image 2: Add light gray connectors.
Image 3: Add the earlier made components.
Image 4: Add the earlier made component.
Images 5-6: Handle and Scope/Sight finished.
Image 7: Handle and Scope/Sight in place.
Image 8: looking down the sight