nguyen joey

Hello fellow nerfers,
I am a relatively new nerfer and this is my first post on NerfHaven.
I apologize if this question has been answered already, but I need to know how long an optimal Titan barrel for a good combination of range and accuracy would be. I have removed the grate-like thing on the end of the missile barrel and glued a coupler there. However, I have not opened it up so I have not done any internal modifications such as plugging the pump. I plan to use my slugs by the way.
Current results are as follows:
12” barrel

Slugs: 120 ft. flat with good accuracy
Stock Streamlines: 150 ft. flat with no accuracy

18” barrel
Slugs: 130 ft. flat with good accuracy
Stock Streamlines: Flies 150 feet, then spirals off

Any help would be appreciated. Thank you in advance.