DescriptionMMS455b shear ram section.png	Cross-section of a typical shear ram used in oil well blowout preventers. Figure from p.12 in MINI SHEAR STUDY for U.S. Minerals Management Service Requisition No. 2-1011-1003, December 2002
Date	December 2002
Source	http://www.mms.gov/tarprojects/455/Final%20Report.pdf
Author	West Engineering Services, Inc.
Permission (Reusing this file)	Public domainPublic domainfalsefalse This article or image contains material based on a work of a Minerals Management Service employee, created as part of that person's official duties. As a work of the U.S. federal government, such work is in the public domain in the United States. See MMS Disclaimer.

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Numbers indicate the forces described in the text of the report.
1) Pressure from the well bore resisting the closure of the ram. 2) Low pressure to return the ram to its open position. 3) High pressure to shear (or snap) the drill pipe. 4) Force from sliding wedge that holds the ram in place, even if hydraulic pressure fails after closing.