First open edit mode (F2), open the blueprint library (F6) and select one of the rifles you want to edit double click it to load it. Save the rifle under a different name.

Open the particles tab and double click the particle system you want to edit. In this case the shot particle system.

Spawn the gun by dragging it into the game from the blueprint library (F6). Now make sure you are in particle edit mode and select the the particle you want to edit on the spawned gun by clicking it.

Shoot the gun to test your particle system or tick emitting in the top of the particle system editor

Now copy the particle system by pressing the copy button on your changed particle system you edited ingame. Then load the particle system of the gun and press the paste button to add your changes to the guns particle system.

Now save your gun blueprint. To share your blueprint just drag the blueprint PNG out of your blueprint library or upload it on the workshop. If you have any questions or got stuck somewhere please don't hesitate to ask.


To find out how to add a custom texture to your gun check out this guide:
https://steamproxy-script.pipiskins.com/sharedfiles/filedetails/?id=647555095