First, check to make sure the gun is unloaded, then check again. Make sure the hammer is cocked ( Magazine removed ) On the right side of the slide ( at the front ) you will find a small arrow, on the front of the frame you will find a small line. Pull the slide back until the arrow and line are aligned , with your third hand turn the barrel 180 degrees, the whole top part will slide forward and off, to reinstall, just reverse the procedure. That is as far as you need to or want to go. If you start driving out pins you will be visiting a gunsmith with all the parts in a paper bag with a hangdog look on your face. Repeat, do not drive out any pins. I'm assuming this is a second issue, not the one with a barrel bushing, if it does have a barrel bushing , post back and we will start over.