How to destroy more than one clone at runtime???

for (int i=0;i<5;i++)

I used this code.but it destroy only one clone not 5.

Thats because the object doesn’t get destroyed til the next frame, so you keep destroying the same object.
Give your bullets a tag and use Unity - Scripting API: GameObject.FindGameObjectsWithTag

Thats also a lot more efficient.

Alternately you could “try” Unity - Scripting API: Object.DestroyImmediate

Im not sure exactly how immediate that is, though.