Generating Multiple Random Number Sets With Even Distribution?

I've managed to write a random number generator that produces multiple sets with no repeating numbers per a set.

Now, to step it up a notch, I'm trying to create an even distribution of the numbers generated which is where I could use a hand. Here's my current code:

Code:
Option Base 1
Sub RandomNumberStrings()
Dim rndno As String, strg As String, msg1 As String
Dim r1() As String, r2() As String

[Code]....

Equaling 500 numbers generated as intended, but my target is to get every number with an equal frequency.