I bought a used pm9 and was cleaning it tonight to get ready for a range trip this week. While cleaning it i realized that with the slide stop removed I cannot rack the slide. With My other Kahrs I can rack the slides with the slide stop removed. Is this normal for the pm9? The gun is also a lot harder than my other kahrs to put back together, as the slide was very difficult to pull to the point that the slide stop could be put back in. Any input would be appreciated thanks.