With a Pattern Master, you can expect 100% in a 20" circle at 40 yrds. shooting #2.
I bought mine after a buddy of mine proved that to me...

I was amazed.
Like stated before though, I wouldn't consider it giving you the ability to shoot further, just kill more of the birds you would normally wound.
There is also a Terror Choke tube out there... 3 different models, which are supposed to be pretty wicked. One model boasts killing geese at up to 80 yards, but what do you do to them when your shooting out of your decoys... ? I think it might be a little over-kill... :-?