The bug

If an egg is given a custom model using the item component system, the particles it produces on collision with a block will be the particles of the given model. However, if a snowball is given a custom model, the particles will always be snowball particles, rather than the particles of the item model.

How to reproduce

1. /give @s minecraft:egg[minecraft:item_model=blue_concrete]

2. /give @s minecraft:snowball[minecraft:item_model=blue_concrete]

3. Throw both

Expected results

The egg would produce blue concrete particles, and the snowball would also produce blue concrete particles.

Actual results

The egg correctly produces blue concrete particles, but the snowball unexpectedly produces snowball particles.

How to fix

Make snowballs use the particle associated with the item model.