It really works well, mix the bondo up hot (Que Karl) so that it sets quick. You will need to make a container or edge if you will to hold it. I just used some cardboard and duct taped it up encompassing the grip. Once the bondo started setting a bit I put my hand in and established the grip I wanted. Then just kind of waited to pull my hand out. I used a super thin latex glove smeared with hand cleaner so I had a good release. (Karl is going to fillet me) For competition be careful if there is a weight stipulation in your class. One thing for sure once molded you can only grab the pistol one way. That goes a long way towards improving your scores. Maintaining a consistent grip is key.