Vid-20220418-wa0011mp4 -

"Proper paper" in the context of slinging.org likely refers to:

Specific types of paper or cardboard used for making targets. VID-20220418-WA0011mp4

I cannot play the video to confirm, but I suggest checking the slinging.org forum for the thread matching that attachment name for the exact context, as attachments there often depict experiments with different materials. "Proper paper" in the context of slinging

Based on searches, the file VID-20220418-WA0011.mp4 appears to be a video attachment in the slinging.org forum . This community often discusses creating, using, and repairing slings. This community often discusses creating

If you can tell me is in the video or what material they are using, I can give you more specific information on that technique. Directory /forum/yabbfiles/Attachments - Slinging,org

Using tightly rolled paper or improvised paper materials for ammo.

Documentation or instructions referenced within the forum attachments, potentially describing the use of a "proper" projectile.