Thanks. Do you remember why it was changed in Beta? Ammo dice just seem so cool
I would assume that the Alpha was closer to the original author's vision of how combat would play out.
Not necessary. The alpha version of the rules are a rough draft of the rules and changes made are just adjustments based on alpha-feedback and their own play-testing.
The difference between the alpha and the finalized version with ammo dice is that they are better now. In the alpha, ammo dice can be used to cause additional hits on the primary target or on a secondary target and of course hitting or not, any ammo dice hit can cause suppression. In the finalized rules, ammo dice can also be used to increase damage to another of your hits. This makes ammo dice much better now and much more versatile than they where in the alpha (where they could only cause weapon damage and just because of that couldn't crit a target).
So the difference between the alpha and beta is mainly that you can do one more thing with them (increase damage) than they could do in the alpha.