I took somebody's advice and ordered a peep sight ("One Ragged Hole" ) for my Bisley and it is great. I can shoot better groups quicker than with the factory notched blade. If your eyes are older (mine are 54) give them a try, it helps. I ordered the sight blades and got them in 4 or 5 days. They send 2 blades but the largest one is about the size of a pencil. I used the smaller one.