1. Open up FO4Edit and on module selection right-click and go to the 'Select none' option. Then tick the box next to 'jsrs.esp' and the mod you want to edit. In this example I will use the Kar98k mod by ShaquilleWang. Click ok.

2. Right-click on the weapon mod .esp and select 'Add Masters' and choose 'jsrs.esp'. Note: the weapon mod should be lower than JSRS in the load order for this to work.

3. Expand the weapon mod esp, and then expand the weapon branch. Click on the weapon you want to edit and scroll down to keywords. There will be a sound keyword with the prefix 's_40'. In the case of the Kar98k mod this keyword is 's_40_Kar98k'.

4. Now expand jsrs.esp and then expand the keyword branch. Find the keyword you want to use and take note of its form id. In this case I want to use the 'JSRS_s_40_K98' keyword, which has the form id 10055A8.

5. Going back to the weapon mod esp, select the weapon again and scroll down to keywords. Right click on the keyword you want to change and edit the value to the form id from step 4.

6. Its done. Exit and save the edited esp.