VSR-10 hopup concave nub

Made for my JG BAR-10. The dreaded right hook hop on anything heavier than .2g struck! Then the stock arm only being able to hop .28g effectively.

serves as a self-shimming nub, lifting heavier bb's with less fps loss. compared to a stock hu that is.

installation:

1. turn the stock bucking inside out

2. cut off the stock rubber bucking 'nub' and gently sand/file the inside bucking.

3. cut/file the 2 prongs on stock hop arm FLUSH and even as you can

4. glue this nub exactly w