I have an empirical problem with pulled bullets because I believe that grabbing the bullet to get enough grip to pull them out can potentially “squished” them a bit. Since bullets are basically a soft bag of lead covered by a slightly tougher coat of brass, I believe that the squished bullets can end up having slightly different ogive shapes and bearing surface lengths. If you want to use pull bullets for something important such as a competition or load development, I would suggest at least measuring them via these parameters against new bullets just to make sure this has not happened.