Much to the annoyance of many, the weapon preview screen where you modify your parts and whatnot, has a very oddly zoomed out weapon with no option to zoom in.
The mod adds a zoom (with a mousewheel) to the menu + the ability to move the weapon by holding right click so you can see your weapon to the its fullest.

Source code https://github.com/Luffyyy/PD3-BetterWeaponPreview