Why are USphereComponent InitSphereRadius and SetSphereRadius not changing the radius of my USphere component?

I have a pawn class written in C++ that has a USphereComponent attached to it like so:

MYCLASSNAME.h

   class MYPROJECT_API AMYCLASSNAME : public APawn{
         UPROPERTY(BlueprintReadWrite)
         USphereComponent* SecondarySphere;
    }

MYCLASSNAME.cpp

// Constructor
AMYCLASSNAME::AMYCLASSNAME()
{
 	// Set this pawn to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;

	SecondarySphere = CreateDefaultSubobject<USphereComponent>(TEXT("SecondarySphere"));
	SecondarySphere->InitSphereRadius(3000.0f);
	SecondarySphere->SetSphereRadius(300000.0f);
	SecondarySphere->SetupAttachment(RootComponent);
	SecondarySphere->OnComponentBeginOverlap.AddDynamic(this, &AMYCLASSNAME::OnSphereComponentOverlap);
	SecondarySphere->OnComponentEndOverlap.AddDynamic(this, &AMYCLASSNAME::OnEndSphereComponentOverlap);
}

I’ve played around with a couple of different values for InitSphereRadius, and SetSphereRadius, but neither of them appear to alter the size of the inherited component (on a blueprint child of AMYCLASSNAME). I’m sure I’m missing something simple, but I’m not sure what. Detailed explanations of “why” are appreciated as well as any ideas on how I should troubleshoot this problem.

Try attaching it to a scene component or make it the root component of the actor before calling SetSphereRadius()