Improving script performance

I have a script to manage the weapons my character is carrying, and allows swapping and dual wielding. It works fine, except it slows the FPS from about 60 to 30 or so. I know this script is the problem, I just don't know which part, which is why I have had to put in the whole script below. Please could someone tell me whhat I am doing wrong and how to fix it?

 #pragma strict
 
 var weaponReady : Transform;
 
 //WEAPONS
 
 var weaponA : Transform; //PRIMARY WEAPON
 
 var weaponB : Transform; //SECONDARY WEAPON
 
 var weaponC : Transform; //DUAL WIELDED WEAPON
 
 var tempWeapon : Transform;
 
 //PLACES TO STORE WEAPONS
 
 var hand : Transform; //PRIMARY WEAPON
 
 var back : Transform; //SECONDARY WEAPON
 
 var holster : Transform; //PISTOLS, SWORDS STORED HERE
 
 var leftHand : Transform; //USED WITH ONE HANDED WEAPONS AND DUAL WIELDING
 
 var rightHand : Transform; //USED WITH ONE HANDED WEAPONS AND DUAL WIELDING
 
 //SCRIPTS ASSIGNED AUTOMATICALLY
 
 var weaponAScript : WeaponScript;
 
 var weaponBScript : WeaponScript;
 
 var weaponCScript : WeaponScript;
 
 var tempScript : WeaponScript;
 
 //BEGIN FUNCTIONS
 
 function Start () {
 
 //LOOK FOR WEAPONS AND ASSIGN THEM PROPERLY
 
 if(weaponA)
 {
 weaponAScript=weaponA.GetComponent(WeaponScript);
 
 weaponAScript.enabled=true;
 
 if(weaponC)
 {
 weaponA.rigidbody.constraints=RigidbodyConstraints.FreezeAll;
 weaponA.rigidbody.detectCollisions=false;
 weaponA.collider.enabled=false;
 weaponA.parent=leftHand;
 weaponA.localPosition=Vector3.zero;
 weaponA.rotation=leftHand.rotation;
 weaponAScript.dualWielding=true;
 }
 else
 {
 weaponA.rigidbody.constraints=RigidbodyConstraints.FreezeAll;
 weaponA.rigidbody.detectCollisions=false;
 weaponA.collider.enabled=false;
 weaponA.parent=hand;
 weaponAScript.dualWielding=false;
 weaponA.localPosition=Vector3.zero;
 weaponA.rotation=hand.rotation;
 }
 }
 
 if(weaponB)
 {
 
 weaponBScript=weaponB.GetComponent(WeaponScript);
 
 weaponBScript.enabled=false;
 
 weaponB.rigidbody.constraints=RigidbodyConstraints.FreezeAll;
 weaponB.rigidbody.detectCollisions=false;
 weaponB.collider.enabled=false;
 weaponB.parent=back;
 weaponB.localPosition=Vector3.zero;
 weaponB.rotation=back.rotation;
 weaponBScript.dualWielding=false;
 }
 
 if(weaponC)
 {
 
 weaponCScript=weaponC.GetComponent(WeaponScript);
 
 weaponCScript.enabled=true;
 
 weaponC.rigidbody.constraints=RigidbodyConstraints.FreezeAll;
 weaponC.rigidbody.detectCollisions=false;
 weaponC.collider.enabled=false;
 weaponC.parent=rightHand;
 weaponC.localPosition=Vector3.zero;
 weaponC.rotation=rightHand.rotation;
 weaponCScript.dualWielding=true;
 }
 
 }
 
 //INITIALISATION OVER
 
 function Update() {
 if(Input.GetKeyDown(KeyCode.Q))
 {
 if(!weaponReady)
 {
 SwapWeapons();
 }
 if(weaponReady&&weaponC)
 {
 PickupWeapon("left");
 }
 if(weaponReady&&!weaponC)
 {
 PickupWeapon("left not dualing");
 }
 }
 
 if(Input.GetKeyDown(KeyCode.E))
 {
 if(weaponReady&&weaponC)
 {
 PickupWeapon("right");
 }
 if(weaponReady&&!weaponC&&weaponB)
 {
 PickupWeapon("primary");
 }
 if(weaponReady&&!weaponC&&!weaponB)
 {
 PickupWeapon("primary no secondary");
 }
 }
 }
 
 function SwapWeapons () {
 
 //DROP DUALWIELDING WEAPON
 if(weaponC)
 {
 DropWeapon(weaponC);
 weaponC=null;
 }
 //REASSIGN WEAPONS
 tempWeapon=weaponA;
 weaponA=weaponB;
 weaponB=tempWeapon;
 //REASSIGN SCRIPTS
 weaponAScript=weaponA.GetComponent(WeaponScript);
 weaponBScript=weaponB.GetComponent(WeaponScript);
 //MOVE THEM AROUND
 weaponA.parent=hand;
 weaponA.localPosition=Vector3.zero;
 weaponA.rotation=hand.rotation;
 weaponAScript.enabled=true;
 weaponB.parent=back;
 weaponB.localPosition=Vector3.zero;
 weaponB.rotation=back.rotation;
 weaponBScript.enabled=false;
 }
 
 //STANDARD WEAPONDROP SCRIPT
 function DropWeapon (weapon : Transform) {
 weapon.Translate(1,0,0);
 weapon.parent=null;
 weapon.rigidbody.constraints=RigidbodyConstraints.None;
 weapon.rigidbody.AddRelativeForce(transform.forward*100);
 var weapScrip=weapon.GetComponent(WeaponScript);
 weapScrip.enabled=false;
 weapScrip.dualWielding=false;
 yield WaitForEndOfFrame;
 weapon.collider.enabled=true;
 weapon.rigidbody.detectCollisions=true;
 }
 
 //WEAPON SWAPPING
 function PickupWeapon (newGunHand : String) {
 if(newGunHand=="left")
 {
 DropWeapon(weaponA);
 weaponA=weaponReady;
 weaponAScript=weaponA.GetComponent(WeaponScript);
 
 weaponAScript.enabled=true;
 
 weaponA.rigidbody.constraints=RigidbodyConstraints.FreezeAll;
 weaponA.rigidbody.detectCollisions=false;
 weaponA.collider.enabled=false;
 weaponA.parent=leftHand;
 weaponA.localPosition=Vector3.zero;
 weaponA.rotation=leftHand.rotation;
 weaponAScript.dualWielding=true;
 weaponReady=null;
 }
 if(newGunHand=="right")
 {
 DropWeapon(weaponC);
 weaponC=weaponReady;
 weaponCScript=weaponC.GetComponent(WeaponScript);
 
 weaponCScript.enabled=true;
 
 weaponC.rigidbody.constraints=RigidbodyConstraints.FreezeAll;
 weaponC.rigidbody.detectCollisions=false;
 weaponC.collider.enabled=false;
 weaponC.parent=rightHand;
 weaponC.localPosition=Vector3.zero;
 weaponC.rotation=rightHand.rotation;
 weaponCScript.dualWielding=true;
 weaponReady=null;
 }
 if(newGunHand=="primary")
 {
 DropWeapon(weaponA);
 weaponA=weaponReady;
 weaponAScript=weaponA.GetComponent(WeaponScript);
 
 weaponAScript.enabled=true;
 
 weaponA.rigidbody.constraints=RigidbodyConstraints.FreezeAll;
 weaponA.rigidbody.detectCollisions=false;
 weaponA.collider.enabled=false;
 weaponA.parent=hand;
 weaponA.localPosition=Vector3.zero;
 weaponA.rotation=hand.rotation;
 weaponAScript.dualWielding=false;
 weaponReady=null;
 }
 if(newGunHand=="primary no secondary")
 {
 
 weaponB=weaponA;
 weaponBScript=weaponB.GetComponent(WeaponScript);
 weaponB.parent=back;
 weaponB.localPosition=Vector3.zero;
 weaponB.rotation=back.rotation;
 weaponBScript.enabled=false;
 
 weaponA=weaponReady;
 weaponAScript=weaponA.GetComponent(WeaponScript);
 
 weaponAScript.enabled=true;
 
 weaponA.rigidbody.constraints=RigidbodyConstraints.FreezeAll;
 weaponA.rigidbody.detectCollisions=false;
 weaponA.collider.enabled=false;
 weaponA.parent=hand;
 weaponA.localPosition=Vector3.zero;
 weaponA.rotation=hand.rotation;
 weaponAScript.dualWielding=false;
 weaponReady=null;
 }
 if(newGunHand=="left not dualing")
 {
 weaponA.parent=rightHand;
 weaponA.localPosition=Vector3.zero;
 weaponA.rotation=rightHand.rotation;
 weaponAScript.dualWielding=true;
 weaponC=weaponReady;
 weaponCScript=weaponC.GetComponent(WeaponScript);
 
 weaponCScript.enabled=true;
 
 weaponC.rigidbody.constraints=RigidbodyConstraints.FreezeAll;
 weaponC.rigidbody.detectCollisions=false;
 weaponC.collider.enabled=false;
 weaponC.parent=leftHand;
 weaponC.localPosition=Vector3.zero;
 weaponC.rotation=leftHand.rotation;
 weaponCScript.dualWielding=true;
 weaponReady=null;
 }
 }
 
 function OnTriggerStay (col : Collider) {
 print("collision");
 if(col.transform.GetComponent(IncativeWeapon)){
 print("weapon is ready");
 weaponReady=col.transform;
 }
 }