Call me slow (I read as much as I could about mag springs on the forum) but I am still confused. I just took apart one of the two 15 round mags that came with my new M9A1 (on the left). I then compared it to the 14-round mag I just purchased from CDNN (on the right) marked, "Restricted Law Enforcement Govt Use and Export Only 9/14/94, GSI Trussville, AL." As you can see the 15-round mag has a much longer magazine spring and since I have experienced some failures of the slide to stay open on the last round (though I didn't check to see which mag), I am wondering if this has something to do with it. Is this normal? If so, what to do? Spring experts please help, thanks.