TT-33 pistol and it's variants are great for the DIYer gun nut. There's even a nice Sticky about working on the TT on the Pistol & Revolver forum here:
https://www.canadiangunnutz.com/for...-To-Smooth-Action-and-Trigger-and-Useful-Tips
https://www.canadiangunnutz.com/for...-To-Smooth-Action-and-Trigger-and-Useful-Tips