Electronic Assassinations Newsletter

Issue #2 "New Discoveries in the Recently Released Assassination Files"

Blakey's "Linchpin":
Dr. Guinn, Neutron Activation Analysis, And The Single Bullet Theory
Part 2

Wallace Milam


1. On September 8, 1978, Dr. Guinn told HSCA his tests showed that only 2 bullets struck Governor Connally and President Kennedy. "There is not evidence for three bullets, for four bullets or anything more than two, but there is clear evidence that there were two." (HSCA, I, p. 504)

2. Guinn found that the two fragments removed from Kennedy's brain and fragments from the interior of the limousine were parts of the same bullet. He based this conclusion on the claimed homogeneity of their antimony content-621 ppm for the brain fragments and 638 ppm, 647 ppm, and 602 ppm for the pieces of metal from the car. (HSCA, I, p. 538)

3. Alleged homogeneity of antimony content was also the basis of Guinn's statement that the fragments removed from Governor Connally's wrist matched drillings taken from the lead core of CE 399, the famous bullet allegedly found in a stretcher at Parkland Hospital. The three wrist fragments contained 797 ppm of antimony, while the stretcher bullet showed 833 ppm. [The 797 ppm measurement given for the three wrist fragments is puzzling. Guinn's tables show that he took 2 samples from CE 842 for testing but these 2 samples were really 3 separate specimens. He identified a "single larger specimen" of 16.4 milligrams and "two tiny specimens" of 1.3 milligrams. He gives only one antimony measurement for CE 842-797 ppm. Yet, as we shall see, the likelihood of 3 pieces of metal from any bit of Mannlicher lead having the precise amounts of antimony present is extremely dubious.]

4. Thus, the evidence Dr. Guinn presented to the committee reinforced the previous findings of the Warren Commission and provided a "scientific" basis for the later findings of the House Select Committee on Assassinations:

a. The finding that only two bullets struck the car and its occupants is consistent with both the earlier Warren Commission conclusions and the later HSCA report.

b. The finding that all bullet leads involved were of WCC Mannlicher-Carcano manufacture tied the fragments to evidence on the sixth floor of the Texas School Book Depository.

c. The finding that fragments from Connally's wrists were from the stretcher bullet made the single-bullet theory scientifically possible and elevated the stretcher bullet, once called the "bastard bullet," to the status of key and legitimate evidence.

d. Dr. Cyril Wecht had testified before the committee earlier in the same afternoon as Guinn. Wecht had raised many objections to the single-bullet theory, one being that the bullet involved would have to have been more deformed. Counsel Wolf asked Guinn about Wecht's belief.

WOLF. Dr. Guinn, on the basis of your scientific analysis, do you believe Dr. Wecht to have been correct?

GUINN. Well, I think that is his opinion, but like many opinions and many theories, sometimes they don't agree with the facts. (HSCA, Vol. I, p. 505)

5. Dr. Guinn had apparently brought the committee "the facts."


1. But what is the evidentiary basis for Dr. Guinn's "facts"? He clearly based his entire neutron activation analysis in this case on the proposition that Western Cartridge Company Mannlicher-Carcano ammunition varied greatly from bullet to bullet but showed homogeneity within a given Mannlicher bullet. This turns out to be contradicted by the results of Dr. Guinn's own tests.

2. As Mr. Wolf prepared Dr. Guinn for the coup de gras by having him state his finding that it was "highly probable" that the fragments found in Connally's wrist came from CE 399, Dr. Guinn made these remarks:

"One can only show what information we have, and that is that you simply do not find a wide variation in composition within individual WCC Mannlicher-Carcano bullets, but you do find wide composition differences from bullet to bullet, for this kind of bullet lead." (HSCA, Vol. I, p. 505. Emphasis added.)

3. But a study of "what information we have" shows (a) that Dr. Guinn had very little information on which to base any conclusion about intra-bullet homogeneity, (b) that tests performed in his own laboratory revealed great variations, some of over 100%, in the antimony content of test fragments taken from a single Mannlicher bullet, bringing into question the data on which Dr. Guinn based all his important findings given to HSCA; and (c) that Dr. Guinn had given a quite different interpretation of homogeneity within individual Mannlicher bullets in a paper he had recently written.

4. During the years 1973-75, Dr. Guinn performed tests on bullet samples from the 4 production lots of Western Cartridge Company Mannlicher bullets made available to him by Dr. Nichols. In addition to testing bullets from different lots, Guinn, on one occasion took one bullet each from lots 6001, 6002 and 6003, then broke each of the chosen bullets into 4 fragments. NAA tests for composition of antimony, silver, and copper were then run on the bullet fragments.

5. The results are printed on page 549 of Volume I of the HSCA Hearings and they are astonishing,, especially in the light of Dr. Guinn's subsequent statement that "you simply do not find a wide variation in composition within individual WCC Mannlicher-Carcano bullets."

a. The 4 fragments from one bullet from lot #6002 showed the following antimony composition: 358 ppm, 983 ppm, 869 ppm, and 882 ppm. This represents a variation of 625 parts-per-million between two of the fragments.

b. The 4 fragments from one bullet from lot #6003 showed the following antimony composition: 667 ppm, 395 ppm, 363 ppm, 441 ppm. This represents a variation of 304 parts-per-million between two of the fragments.

c. The 4 fragments from one bullet from lot #6001 showed the following antimony composition: 1139 ppm, 1062 ppm, 1235 ppm, and 1156 ppm This represents a variation of 173 parts-per-million between two of the fragments.

6. It appears that on the day Dr. Guinn told HSCA that "you simply do not find a wide variation in composition within individual WCC Mannlicher-Carcano bullets," the entire database on which he relied consisted of three broken WCC Mannlicher bullets, one of which showed an intra-bullet variation of 175%, one of which showed an intra-bullet variation of 84%, and a third which showed an intra-bullet variation of 16%. [See Appendix B for Guinn's test charts, as well as a comparison of intra-bullet variations with lot variations in his tests.] It is reasonable to assume that if Dr. Guinn had performed other tests of fragments from single Mannlicher bullets and they had shown greater homogeneity, he would have included them in his test results. Further, the fact that he worked with only 14 bullets limited the number he had available for fragmenting and testing.

7. It is shocking to learn that the basis for Dr. Guinn's authoritative statements about homogeneity rests on such narrow and contradictory testing. What significance can be given to the presence of ANY given amount of antimony in ANY Mannlicher samples from WCC-whether from Connally's wrist, a hospital stetcher, or Guinn's reactor-when it is realized that another piece of the same lead core, located a millimeter or a centimeter away along the length of the bullet, may vary in its antimony content by as much as 600 ppm, may have half as much or twice as much antimony?

8. What Dr. Guinn really found is that Mannlicher-Carcano bullets cannot be differentiated by NAA. The answer may well lie in the process of their manufacture. The use of recycled lead brings together a potentially very heterogeneous collection of bullet lead. This is shown in the wide variations which Guinn obtained between bullets from different lots and bullets from within the same box. What would be the basis for expecting that unmeasured, heterogeneous, recycled lead could come together homogeneously in a given bullet? If the bullet lead went into the manufacturing process in a heterogeneous form, by what manufacturing step would it be made homogeneous? (Recall that NAA on non-Mannlicher ammunition had yielded homogeneity throughout the analytical process-within bullet makes, within boxes of bullets, and within individual bullets.)

9. Furthermore, there is compelling evidence that Doctor Guinn held the opinion that fragments from an individual Mannlicher bullet were, in fact, HETEROGENEOUS in antimony content instead of homogeneous, as his conclusions required. on the same day that he told Wolf, the HSCA, and the world that "...you simply do not find a wide variation in composition within individual WCC Mannlicher-Carcano bullets," Dr. Guinn submitted a paper said to support that conclusion. In his bibliography he included an article he had co-authored ("Neutron Activation Analysis of Bullet-Lead Specimens: The President Kennedy Assassination," Transactions of the American Nuclear Society, 28 (1978), p. 92-93.) In that article, the same man who told HSCA that variations are not found in WCC Mannlicher bullets wrote, "In the U. C. Irvine INAA [Instrumental Neutron Activation Analysis] background studies of the Mannlicher-Carcano ammunition, it was found that this bullet lead is remarkably HETEROGENEOUS ... SOMEWHAT WITHIN A GIVEN BULLET... (Emphasis added).

10. It is difficult to find a more shocking statement. Homogeneity within a bullet is the key to Guinn's entire interpretation! He swore that there are not wide variations "within individual Mannlicher-Carcano bullets", but he had recently written that there was heterogeneity-not homogeneity-"within a given bullet." When I first discovered this statement, I was overwhelmed by the misuse and perversion of science it implied. Conclusions are inescapable:

a. Tests in Guinn's own lab indicated that fragments from WCC Mannlicher bullets showed more intra-bullet heterogeneity than homogeneity.

b. Nonetheless, Guinn testified that one did not find heterogeneity within individual bullets.

c. Guinn was well aware that his tests indicated heterogeneity instead of the publicly-stated homogeneity.

11. And there is more. In the same article from Transactions of the American Nuclear Society, Guinn quoted results from the FBI's 1964 NAA tests, tests which he insists actually were conclusive, not inconclusive as the FBI reported. [In his HSCA testimony, Guinn told Congressman Fithian that the FBI's scientists had the correct test results back in 1964, but had not made the proper interpretations.] Referring to the FBI tests, Guinn wrote, "....the 17 values obtained for various portions of the 'Connally stretcher' bullet averaged 837 ppm Sb [antimony], but ranged all the way from 636 to 1125 ppm."

a. Amazing. So much for homogeneity within a given bullet. Guinn took one 10.7 mg sample from CE 399, the "stretcher bullet," and found it contained 833 ppm of antimony. This led him to match it with CE 842, the alleged Connally wrist fragments, which contained 797 ppm. That "match" is the scientific underpinning for the single-bullet theory.

b. But Guinn knew the FBI had taken numerous portions from this same bullet and had found no homogeneity among the portions! He had their data before him. Guinn's finding of 833 ppm in a given piece of CE 399 has no meaning because, according to the FBI tests (which Guinn thinks gave accurate data), an adjoining piece of the same bullet had anywhere from 636 ppm to 1125 ppm! Guinn was forewarned of the obvious heterogeneity in CE 399, a heterogeneity he never found because he never took multiple samples.

c. Consider for a moment the ranges the FBI did find in CE 399. A glance at Guinn's charts shows that the piece of CE 399 which had 636 ppm would have most closely matched the fragments alleged to be from the floor of the limousine--not the Connally wrist fragments, while the piece which had 1125 ppm would not fall within 300 ppm of the Connally wrist fragment or any of the other fragments said to be associated with the car or its occupants. The FBI got a lot of things wrong in the Kennedy investigation, but the Bureau was right on target when it called its NAA tests "inconclusive."

12. Dr. Guinn submitted his paper, "A Report to the House of Representatives Select Committee on Assassinations on the subject of 1977 Neutron Activation Analysis Measurements on Bullet-Lead Specimens Involved in the 1963 Assassination of President John F. Kennedy," when he testified on September 8, 1978. Not only did the bibliography contain the disturbing references noted above, the body of his paper included opinions about homogeneity in 6.5 Mannlicher bullets which are both revealing and inconsistent with his sworn testimony:

a. Guinn stated to the committee that "you simply do not find a wide variation in composition within individual WCC Mannlicher-Carcano bullets." His accompanying monograph says "...individual bullets were found to be fairly homogeneous in their Sb and Ag concentrations ... (HSCA, Vol. I, p. 511. Emphasis added)

b. In describing the results of taking 4 pieces of bullet lead from each of 3 Mannlicher bullets [see page 12 and also Appendix C for findings], Guinn stated that the bullet from lot 6001 "is fairly homogeneous for all three elements; one (6002) is fairly homogeneous in Ag and Cu but not so homogeneous in Sb; and one (6003A) is fairly homogeneous in Cu but not homogeneous in Sb and Ag." (HSCA, Vol I, p. 545. Emphasis added) Note that by his own admission, 2 of the 3 bullets were "not homogeneous" and "not so homogeneous" in antimony content, which he had called the most significant from an analytical standpoint.

c. In his conclusion, Guinn wrote, "....the UCI [University of California Irvine] study of MC bullet lead indicates a wide range of Sb values from bullet to bullet, but reasonable homogeneity within an individual bullet." (HSCA, Vol. I, p. 546. Emphasis added.)

d. Is this finally a "battle of adjectives"? Do the terms "fairly homogeneous," "not so homogeneous," and "reasonable homogeneity" justify a scientist stating that "you simply do not find a wide variation" in this type of bullet?

e. No, indeed. There is no battle of adjectives. The facts are clear. Guinn had tested 4 particles each from three bullets and the average range of antimony concentration in the particles from these 3 bullets was 93%! When Guinn stated that "you simply do not find a wide variation in composition within individual WCC Mannlicher-Carcano bullets," he had just completed finding those "wide variations" in his own laboratory. What justification can be found for saying that the 4 fragments from bullet 6002, containing antimony measurements of 358 ppm, 983 ppm, 869 ppm, and 882 ppm, don't have "wide variations"? Or that bullet 6003, containing antimony measurements of 667 ppm, 395 ppm, 441 ppm, and 363 ppm, has "reasonable homogeneity"? [SEE APPENDICES D AND E FOR MORE ON GUINN'S TESTS]

13. From Dr. Guinn's work and the literature available, a new picture of the cores of Western Cartridge Company's Mannlicher-Carcano 6.5 mm bullets emerges. The cylinders were actually composed of hybrids of lead from a variety of sources. Due to recycling, a given bullet could have contained, in one area, recycled hardened lead, with high parts-per-million measurements of antimony. Alongside it, there might have been recycled virgin bullet lead, with very low antimony measurements. And alongside these could have been lead which was the result of "re-recyling," that is, bullet lead which had been a part of bullets or other leaded objects in which no effort had been made to precisely measure the amounts of trace elements present. The nature of the production process eliminated any chance for homogeneity. Dr. Guinn was actually acknowledging this when he wrote in his report to HSCA: "Intermediate Sb levels (between about 10 ppm and perhaps 1500 ppm are encountered in unhardened bullet lead in which some recycled lead is used, along with virgin lead, but in which no Sb has been deliberately added for hardening." (JFK Exhibit F-331, pp. 3-4, published in HSCA Hearings, Volume I, p. 509-510) What Guinn referred to as "deliberately added" would actually mean "measured and added." Predicatably, when all the Sb measurements Guinn submitted to HSCA are reviewed,the range of Sb measurements is from 80 to 1235 p.m., indicating an amalgam of recycled and virgin lead--with no hint of homogeneity at any level--not among bullets of the same production lot, bullets from the same box, or fragments from within the same bullet.

14. Knowing these things enables us to understand why Guinn's measurement of 833 p.m. of antimony in his core sample from CE 399 (the "stretcher bullet")-and his subsequent matching of the bullet to the Connally wrist fragments with their 797 ppm count-are meaningless conclusions. We know (and Guinn knew when he gave his testimony) that the FBI had already taken 17 other bits of metal from that same "stretcher bullet" --with antimony ranges from 636 to 1125 ppm. The lead cylinder at the core of CE 399 is a heterogeneous mixture of recycled leads. Based on the antimony levels found by both the FBI and Guinn, CE 399 was almost certainly composed of recycled lead. Guinn treated it as if it were a uniform cylinder of lead with a constant antimony content throughout, even though he knew the cylinder contains lead areas with a wide range of antimony content. Guinn's work is analogous to the police examining a crime scene, finding 4 fingerprints (in this case actually many more "bullet fingerprints" than that), lifting one set of prints, ignoring the others, then announcing that all the fingerprints are the same and the crime was committed by identical quadruplets!

15. The best which can be said of Guinn's performance is:

a. He proved that neutron activation analysis cannot be used with Mannlicher-Carcano bullets or any other bullets not with carefully-measured portions of lead.

b. He raised serious questions about his own integrity.


1. Dr. Guinn felt he could make his assertions about the nature of Mannlicher bullets with certainty because he believed he had examined bullets from every production lot manufactured by Western Cartridge Company.

WOLF. Did you examine bullets from every lot produced by the Western Cartridge Company?

GUINN. Yes. The Western Cartridge Company reportedly made 1 million rounds of each of 4 production runs, lots 6000. 6001, 6002, and 6003. They were made at different times in 1954, and reportedly those were the only lots they ever produced, and we had boxes from each of those lots. (HSCA, I, p. 494)

2. But Guinn was again in error. His assumptions were false. Western Cartridge Company had produced ammunition for the 6.5 Mannlicher-Carcano before 1954 and this ammunition had found its way into the mainstream of sellers and distributors. This had been told to the Warren Commission fourteen years before Guinn testified:

"on March 23, 1964, Mr. R. W. Botts (District Manager, Winchester-Western) advised the Western Cartridge Company ... manufactured a quantity of 6.5 M/M Mannlicher-Carcano ammunition for the Italian government during World War II. At the end of the war, the Italian Carcano rifle, and no telling how much of this type of ammunition was sold to the United States gun brokers and dealers and subsequently was distributed by direct sales to wholesalers, retailers and individual purchasers." (WC Exhibit 2694, Vol XXVI, p. 62)

3. The purpose of Mr. Wolf's question and Dr. Guinn's answer was clearly to establish the comprehensiveness of the work at Guinn's laboratory and to insure that no kind of 6.5 Mannlicher ammunition had evaded his testing. Once again, Dr. Guinn's answer is at variance with known facts.


1. It is troubling that Dr. Guinn made blanket statements about the characteristics of WCC Mannlicher-Carcano bullets while unaware of the existence of Mannlicher-Carcano ammunition from production lots he had never tested.

2. But these facts should not detract from two other points which go the heart of the findings of the House Select Committee on Assassinations;

a. By his own admission, Dr. Guinn did not examine ANY of the same fragments the FBI had tested earlier, even though the fragments he received for testing bore the same exhibit numbers as those analyzed in 1964, and even though the type of testing done by the FBI would not have destroyed any parts of those fragments. HSCA's explanation for the failure of the samples to match in weight or count is both unsatisfactory and contradicted by Dr. Guinn himself. The purpose of individual exhibit numbers is to lend specificity to the sample. "CE 842" or "CE 567" or any of the other numbers refer to a single entity-or at least they are supposed to do so. In this case, they do NOT, thus throwing into serious question the source and nature of the materials provided Dr. Guinn.

b. From an evidentiary point of view, it wouldn't have mattered which fragments were given to Guinn. The tests he performed, no matter what materials were used, were meaningless. Guinn presented no evidence to support his claim that WCC Mannlicher ammunition could be identified and differentiated by neutron activation analysis; in fact, his own tests and his own earlier interpretation of those tests indicated the opposite. MANY WILL FIND IT SHOCKING THAT KEY FINDINGS IN A 2-YEAR GOVERNMENT INVESTIGATION INTO THE ASSASSINATION WERE BASED ON CONTRADICTORY DATA OBTAINED FROM THREE FRAGMENTED BULLETS AND REPORTED IN A PAPER WHICH WOULD SURELY HAVE BEEN REJECTED BY ANY REPUTABLE SCIENTIFIC JOURNAL.

3. To understand this last statement, it is necessary to return to some points made earlier.

*The first is Guinn's unwillingness to place a numerical probability on his test conclusions. When Wolf tried to get him to do so, the following exchange occurred:

WOLF. What is the degree of confidence and certainty with which you can state this conclusion?

GUINN. I wish I could put a number on it, as we often can do, that is, calculate a probability, but we really don't have the background information to make a numerical calculation in this case...

When Wolf pressed for a more precise answer, he got this response:

GUINN. I would state it is highly probable, yes. I would not want to state how high, whether it was 99 percent or 90 percent, or 99.9 percent.

From a scientific standpoint, this renders Guinn's tests worthless. The principles of scientific research require statements of numerical probability. Without them, test results are devoid of validity.

*The second point is closely related: Guinn failed to perform multiple tests on the same samples, to assure and to document the hypothesis upon which his entire work was based: that the Mannlicher-Carcano bullet really is a homogeneous cylinder of lead, with the amounts of key elements such as antimony and silver being distributed equally throughout. Had he performed such tests and received the same results he had gotten from his 3 previous intra-bullet tests (and that the FBI had gotten in 1964), he would have been forced to conclude that there was no homogeneity within a given Mannlicher-Carcano core, and thus there was no possibility that NAA could do with Mannlicher bullets what NAA could not do with any other bullet leads-assign given fragments to a particular bullet. The failure to do multiple tests on each fragment also served another "useful" function: it allowed Guinn to assign six standard deviations to his measurements, resulting in statistically meaningless conclusions.

4. In fact, Guinn, in his testimony, tended to exaggerate the amount of testing he had done. Even though the paper he submitted made it clear that he worked with only 14 Western Cartridge Company Mannlicher-Carcano bullets (HSCA, Vol. 1, p. 540), 4 each from lots 6001, 6002, and 6003, and 2 from lot 6000, his testimony created the impression that an extensive study was made of the ammunition. Under oath, he described to HSCA counsel Wolf how he discovered that there was no homogeneity among bullets found within a given box or lot: "...when we would take a box of cartridges all from a given production lot, take 1 cartridge out and then another and then another and then another, all out of the same box, boxes of 20, these were, and analyze them, they all in general look different and widely different, particularly in their antimony content." The truth is, "we" (whoever that is) never had a box of 20, never took "one cartridge and then another and then another and then another" from any box, and never took an entire box of cartridges from a given production lot. His own Table II-A, reproduced on page 547 of HSCA's Volume 1, confirms that he tested only a total of 14 bullets from the three production lots.

5. Guinn did do a reproducibility test, in which he took Mannlicher fragments (not from the JFK case) and subjected them to 4 tests in his counter. He found a high degree of reproducibility. (These results are reported in page 548 of HSCA's Volume One.) Of course, it must be understood that here Guinn was testing his equipment, and its ability to reproduce results, not the nature of the metal fragments being tested. Finally, it must be repeated that there is no evidence that Guinn ever sought any evidence by experimentation to prove his statement that Mannlicher cores were "remarkably homogeneous," the very hypothesis on which all his conclusions were based. Indeed, all previous laboratory testing told him quite the opposite.

Go to appendix A

Go to appendix B

Go to appendix C

Go to appendix D

Go to appendix E

Go to appendix F

Go to appendix G

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