Effective May 11, 2009, the Postal Service™ is revising Mailing Standards of the United States Postal Service, International Mail Manual (IMM®) to modify all references of “rifled” and “rifling” to “missing contents.”
We believe that the term “missing contents” is more intuitive for our customers submitting a claim for loss or damage, and that it more accurately conveys that circumstances other than rifling can be attributed to missing contents in an article.
We will incorporate these revisions into the next printed version of the IMM and into the monthly update of the online IMM, which is available via Postal Explorer® at http://pe.usps.com.
— Mailing Standards,Pricing, 5-7-09