I have several low poly models that I have generated colliders for. These include static things like buildings and rocks. I also have projectiles in game that I want to bounce off these static objects.

Here's the problem. Half the time these collisions occur and the other half the projectile goes right through the static objects. I have tried sphere and box colliders, changes in velocity, and changes in collision position. Yet, collision with terrain works perfectly.

Is there some way to avoid this problem? Am I doing something wrong? There is no real scripting involved, just models and colliders. I know how to use triggers but I do not wish to use them.

Thanks