R-Hop using Silicone Glue DIY Hopup AEG

This is my 2nd attemp to make DIY R-Hop using Silicone Glue.
I'm very happy with d result of my 1st try with better BB's range & consistency. But the surface is very rough. So this 2nd attemp is an improvement with better smooth surface. Can apply this DIY method to another barrel with hopup window.

Silicone Glue for Gasket is easy to find on automotive store and around 1 USD.

Before using this i've also try using Sugru & Hot Glue, but the material is to hard for BB's below 430 FPS. Restriction in Indonesia
I've also try silicone straw. It's good result, but very hard to cut & mold it with the precise precision.

Note:
I've already cut the bump inside d Hopup bucking rubber using cutter. U will not be able to see this proses on this video.

Tools:
Red Silicone Gasket Glue (Min. 12 Hours to set)
Steel Diameter under 6mm (can use back of drill bit with smooth surface)
Silicone Tape (fill the gap between steel & barrel)
Pure Silicone Oil

Airsoft Unit:
Umarex G36V
Barrel 509mm Prometheus