Inserting Data For Testing

This is the code I'm using to insert data into a table with data from one table, but changing a single column to prevent duplicates and to increase the number of rows. I know I'm missing something easy, but... what is it?

thx,

Kat

code to create the table:

CREATE TABLE [OrdDetails] (
[OrderID] [int] NOT NULL ,
[ProductID] [int] NOT NULL ,
[UnitPrice] [money] NOT NULL ,
[Quantity] [smallint] NOT NULL ,
[Discount] [real] NOT NULL ,
CONSTRAINT [PK_OrdDetails] PRIMARY KEY CLUSTERED
(
[OrderID],
[ProductID]
) ON [PRIMARY]
) ON [PRIMARY]
GO

I inserted all the data from the [Order Details] table, now I'm trying to reinsert the data but changing the PK constraint to prevent error. Seems like this should work.

truncate table OrdDetails
insert into OrdDetails
select * from [Order Details]

/*note, table has 2155 rows to start*/
Declare @CTR INT,
@CTR2 INT
SELECT @CTR = 0
SELECT @CTR2 = 0
WHILE @CTR < 3000 and @CTR2 < 3000
BEGIN
SELECT @CTR = @CTR + 1
SELECT @CTR2 = @CTR2 + 1
INSERT ORDDETAILS
SELECT @CTR, (ProductID + @CTR2) , UnitPrice, Quantity, Discount FROM [Order Details]
END

I still get primary key errors about not being able to insert dups, this is probably easy, but I'm missing something, help!

kat