That band spring is either broken or is being held down by oil/crud or whatever. It should spring up more than it does without the band in place. I think your problem is not that the band is not going down far enough but that the spring is not popping up when it should. Also, try reversing the band; sometimes the band wears just enough on one side to let the band spring pop up.
To remove the band spring, don't pry it up. If you look on the left side of the stock, opposite the front of the band spring, you will see a little hole. To remove the band spring, insert a punch into that hole and tap GENTLY. The band spring will come out to the right. BE CAREFUL THAT YOU DON'T CHIP THE STOCK IF THE SPRING IS STUCK! Go carefully and slowly.