How can i call actor blurprint class in c++,which is placed in world?

I want to call actor blueprint in my c++ character class to simulate particle effect and sound at location of rifle

You can declare a C++ UFunction as BlueprintImplementable meaning that the actual implementation is delegated to a blueprint graph.

What you have to do is create a function inside your character similar to this:

UFUNCTION(BlueprintImplementable, Category = "Shooting")
void SpawnParticlesAndSound();

Inside a blueprint class derived from your character class you can now override this function inside the event graph and implement your particle/sound emitter logic.

See this for the documentation:

You must also make sure that the access level of this function is not private.