Air Venturi Spiraling

Good conditions are low angle light at your back, preferably shooting into a dark-ish background. The green of a wooded area is sufficient.

Better still, do it at night. Place a flashlight at your side, shining downrange. You’ll see the skirts light up like fireflies.

What nervoustrig said!

The only thing I would add is to set the parallax on your scope so that the area of interest is in focus. For my PCPs that's 35 to 45 yards.

Cheers!

slow motion video is also helpful for discovering spiraling pellets

Ideally you need the sun to be low and behind you with the magnification set to about 10 x . Shoot at a light target at say 100 yards but with you parallax set to about 50 yards. I can track .177 pellets with my old eyes so larger calibres should be easy.

Shooting up towards a white cloud does work but be mindful of where the pellet is going to land.

Bb

Using white-out on the skirt of the pellet helps as well.