Editing Single-bullet theory (section)

===Forensic use of compositional bullet lead analysis===
The technique used by Guinn to analyse the bullet lead from the JFK assassination was a form of what has become known as Compositional Bullet Lead Analysis (CBLA). Until 2004 the FBI used this technique to determine whether a crime scene bullet lead sample came from a particular box of ammunition or a particular batch of bullets. Guinn claimed that with the JFK bullet fragments, the technique could be used to identify the exact bullet the fragments came from.

The validity of CBLA was discredited in a 2002 paper ("A Metallurgical Review of the Interpretation of Compositional Bullet Lead Analysis" (2002), 127 Forensic Science International, 174–191)<ref>http://www.dufourlaw.com/JFK/randich_2002_FSIpaper.pdf{{full citation needed|date=December 2013}}</ref> co-authored by Randich and by former FBI Chief [[Metallurgist]], William Tobin.

The 2002 Tobin/Randich paper prompted the National Academy of Sciences (Board on Chemical Science and Technology) to review the science of bullet lead analysis. In a report in 2004<ref>{{cite book |url=https://archive.org/details/forensicanalysis0000nati |title=Forensic Analysis Weighing Bullet Lead Evidence |publisher=Books.nap.edu |date=October 11, 2002 |access-date=August 3, 2010 |doi=10.17226/10924 |isbn=978-0-309-09079-7 |url-access=registration }}</ref> the NAS found the scientific basis for matching bullet sources from the analysis of bullet lead composition as practiced by the FBI was flawed. As a result of that report, courts appear to have stopped accepting this evidence<ref>{{cite web|url=http://www.abanet.org/crimjust/cjmag/21-4/ScientificEvidence.pdf |title=Criminal Justice Section &#124; Criminal Justice Section |publisher=Abanet.org |access-date=January 5, 2013}}</ref> and the FBI has stopped using bullet lead analysis for forensic purposes.<ref>{{cite web|url=https://www.fbi.gov/news/pressrel/press-releases/fbi-laboratory-announces-discontinuation-of-bullet-lead-examinations
|title= FBI Laboratory Announces Discontinuation of Bullet Lead Examinations|publisher = FBI National Press Office}}</ref>

The NAS report on CBLA, and its relevance to the Guinn's analysis of bullet lead in the JFK assassination, is the subject of comment by Randich and Grant in their 2006 paper at page 719.<ref>http://www.dufourlaw.com/JFK/JFKpaperJFO_165.PDF{{full citation needed|date=December 2013}}</ref>