This mornings newsletter from Alan Korwin (
http://www.pagenine.org ) contained the following
CORRECTION:
There is a (seemingly) good reason for the civilian ban on some 9mm +P+ ammo the police like: its pressure falls outside SAAMI specifications, creating a potential litigation problem, so most manufacturers won't warranty its use (though Glock does). Police departments are required to sign a release to get it. Thanks for the note: Jerry C.