I've been playing for about 30 years off and on and I had never hit a shank in my life until 6 months ago when I was fitted and purchased a set of Ping G20's. My guy fitted me for silver dot 1-1/2" over. They felt good on the first dozen shots or so, then BAMMO! Shank! SHANK! SHANK! SHANK!..........it went on for about a week. Then I took a lesson to get rid of it. I ended up getting rid of the irons and going back to my mizuno mx-20's. they are bent 2 degrees upright and have a 1" over length shaft in them. No shank.
Then one day I was playing with the G20's and I hit a shank on the first hole. A guy I was playing with, a complete stranger, says I bought a set of those because I wasnt playing golf much and just wanted something super easy to hit so I bought those, I ended up going back to my G5's he says, wanna hit them? I said sure, bam! No shank. He let me hit them on every shot the rest of the round, he must of been an angel or something. When I got home I went directly to ebay and bought a set for $150. Shanks all but disappeared. they do show up every once in a while but I can totally tell its because I'm swinging to much from out to in.
One thing the pro had me do was hit hosel rockets on purpose. Once I did, he said now dont hit them on purpose. He also explained that hitting shanks is caused by hitting the hosel with a wide open face, you can do this swinging in to out or vice versa. He also said that snatching the club to far inside sets you up for this and that having clubs with huge offset like the G20's would/could exacerbate the problem and that the shanks have been lurking in my swing for years, just waiting for the right time to come out.
Lengthy I know, but thats what she said!
Tim