Well, I took my friends Beretta to the line last Sunday, started at station 1 which just happens to be my nemesis for some reason. Missed the first two birds, on the third I got it down-pat. Only scored a 21 with a gun I had hardly used, no middle bead to look-at. I then took my gun to the line, ignored the middle bead, broke 23.
So my take is..............Take the middle bead off, get the gun to fit you, or find a different gun that does fit you.
I also took a look at the other guns on the rack, three others had no middle bead, and those fellas were hitting at least 20 per round.
My friend asked me how I was lining-up my shots and how much of the rib I saw when I used his gun. My answer: NO CLUE! I put the gun where it felt right, kept the gun moving as I pulled the trigger. He then started to get the hang of it and was shooting 20+ the rest of the day!