If player select custom model e.g.: brush_egypt_desert_1 I can't hit and kill him

[Toxys]

Yes, but it can be done because I saw it on some other servers... or they changed the bullet of e.g.: kar98k to a rocket launcher projectile and that's why they can kill those models?

Look at this video: https://youtu.be/ZyJK0oobMGs?t=247 they're did it many years ago...