i'm at it again.every thing ready to start the smily ramp mod. and i can't get the gun apart. put my manual where i wouldn't lose it and now i can't find it. retracted the slide and took out the assembly pin and the slide will NOT come off the grip! moves forward about an eighth of an inch and stops.i have cajoled, cursed, popped a nitro and finally put it down. what am i doing wrong?