I fixed Double-Barrel Shotgun that to be closer to my own experience with my Italian double-barrel shottie.
It has a roughly 50mt effective shot range and tighter spread.

Double Barrel - Less spread More range

Changed spread reduction from Long Barrel from -50% to -80%, increased range by 50%.

Short Barrel and Sawn off barrel tweaks

Optional file adds +50% range to Short Barrel and Sawed-off barrel, while also reducing spread reduction factor of Short Barrel from -25% to -50%.

Changed spread reduction from Long Barrel from -50% to -80%, increased range by 50%.

Damage

Option file increases damage from 45 to 75

BOOM!

Modifies sound with a more badass one, listen it here.

KA-BOOM!

Same but with the KA-BOOM effect, listen it here.

I also strongly recommend Weapon Damage Overhaul which gives it better damage.