Problem with mesh collider

I have this scene:

The player (behind the button for now) fires bullets, which are sphere objects. The direction, power and height can be modified using the slider, the problem is, sometimes the object will go through the rings instead of hitting them.

This only happens sometimes but I don’t know how to fix it, does anyone have any tips for me?

It all depends on how fast you are shooting your bullet. The Unity engine can’t handle fast objects very well so sometimes they will just go through the object instead of hitting it, in your case the rings.

One easy solution would be to increase the size of the bullet’s collider or the size of rings collider, or both.

Another solution would be to change the frequency in which Unity makes its physics calculations. You can do that in the Time Manager which is found under edit/project settings/time. Make sure not to change the frequency too much as that could cause your game to become very slow and lag.

The third thing you could try is using a raycast. You can find the script here: collision detection problem in fast moving object - Unity Answers

Hope this helps!