Don't try and change sights unless you really know what you are doing and have all the right equipment. Tried to remove the front sight from a new pistol a couple days ago and could not get it all the way off using a general purpose one size fits all sight pusher. Made the mistake of putting it in a vise and even though I had it padded and thought I had everything under control ended up cracking the lower left portion of the slide. The story continues as I took it to a gunsmith and had the sight removed and the new one put on as I did not realize at the time that I'd already cracked the slide. So as a result of wanting to be an amateur gunsmith to save a few bucks the cost of the attempted savings is $40.00 to put the new sight on and $350 for a new slide with night sights. A costly folly on my part that taught me a good lesson. Let the professionals do it.