Since the only mod that enables SDAR with attachments is outdated, so I tried to tweak the data by myself, and turned out it works perfectly!
https://steamcommunity.com/sharedfiles/filedetails/?id=1358252407
This is my first mod, I simply added some scripts from other rifles. I found this gun doesn't support any muzzle and side rail attachments (they are invisible if I added them), therefore I only enabled scopes. If anyone who is experienced with modding wants to change it, feel free to do it.
Notes: I also disabled firing under water function because I want it to become a "regular" SDAR rather than an underwater version. Iron sight zeroing is 100 instead of 30, maximum zeroing is now 600.
Accuracy gets improved a little bit, not sure if it's working, I only changed dispersion stats.