LOL, I just love to read replies like this quote above,
And I love guys who think that because one exception to a rule can be pointed out that it changes the rule. Sorry but 95 percent of the time if you invest the same amount of time and money into guns of the same type a 12 gauge will out pattern a 20. I shoot heavier than lead shot through mostly Indian Creek chokes. No matter how good DTL shot and good chokes might make a 20 gauge they will typically make the 12 gauge that much better still. Volume of shot, it's a good thing.
But by all means go compete in a NWTF shoot with your 20 gauge against all the 12 gauges on the line. If you beat them you can come back and give me all kinds of heck about it. You won't though. Sorry.
So lets review. What's the only advantage a 20 gauge has over a 12 gauge? It's lighter just like I said before. Class dismissed.