Mhw: missing parts?

Ch
- in PlayStation
2

Does anyone happen to know which parts I need to improve the light bow rifle in Monster Hunter World (Iceborn)? At the moment I'm using the "Throne Robber Crimes +" bow rifle on the thunder element tree, but for the last improvement I'm missing parts with a "?" Marked are. Does anyone know which they are and where I get them from? Play on JR 76 and MR 57 on Ps4 if that's useful.

vo

Read for yourself: http://mhgen.kiranico.com/de/leichtbogngwhr/thronraubrverbrechen

vo

https://monsterhunterworld.wiki.fextralife.com/Despot's+Wildfire