I have some trouble with my left thumb and racking the slide on my Shield is sometimes difficult. I don't know the proper term but I use the reach over the top of the slide not the "sling shot" method. Was also wondering if some small pieces of skate board tape would help (also a lot cheaper )
It might help. OR switch to the sling shot method. I find it very difficult to use the hand over the top method on any pistol. It's ok when the slide is locked back already, but from a closed slide, it is harder than the sling shot method. I wish I could do it as easily as Hikok45, if you have ever seen any of his videos.
I have a slide racker on my Pro 9L because the Match Dot gets in the way and I din't need the rear sight so installed the racker in the dovetail. Hook it with one finger and rack it. My 40 Shield was tough at first but I got so it was easy to sling shot it.