75 The Small Arms Review • Vol. 12 No. 9 • June, 2009 Visit SAR on line at: www.smallarmsreview.com Not surprisingly, many of the Thomp- sons used by gangsters had their serial numbers obliterated. This article exam- ines the practice of serial number re- moval by criminals and their recovery by forensic firearm examiners. Gang- sters of that period did not know it, but there is a hidden number on all early Thompsons. We will describe how to reveal these numbers using an amnesty- registered gangster Thompson and why even today, these techniques can shed new information about the history of The Colt Thompson submachine gun has become the icon of orga- nized crime and the gangsters of the 20s and 30s. Indeed, its use by criminals who made the twenties roar was a leading cause of the Na- tional Firearms Act of 1934. Lead photo, above : Thompson with obliterated serial number used in 1928 by Fred “Killer” Burke to mur- der Frankie Yale in New York City. (Courtesy of the New York City Police Museum) Righ t: Obliterated (A) and recovered (B) serial number on a semiautomatic pistol. (Courtesy of Marc Dupre, FoCoSS Forensics)
Not surprisingly, many of the Thomp-sons used by gangsters had their serialnumbers obliterated. This article exam-ines the practice of serial number re-moval by criminals and their recoveryby forensic firearm examiners. Gang-sters of that period did not know it, butthere is a hidden number on all earlyThompsons. We will describe how toreveal these numbers using an amnesty-registered gangster Thompson and whyeven today, these techniques can shednew information about the history of
The Colt Thompson submachine gun has become the icon of orga-nized crime and the gangsters of the 20s and 30s. Indeed, its use bycriminals who made the twenties roar was a leading cause of the Na-tional Firearms Act of 1934.
Lead photo, above: Thompson withobliterated serial number used in1928 by Fred “Killer” Burke to mur-der Frankie Yale in New York City.(Courtesy of the New York City PoliceMuseum)
Right: Obliterated (A) and recovered(B) serial number on a semiautomaticpistol. (Courtesy of Marc Dupre,FoCoSS Forensics)
76 The Small Arms Review • Vol. 12 No. 9 • June, 2009
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these nearly century-oldsubmachine guns.
Crime: Some ThingsNever Change
Law enforcement organi-zations are extremely inter-ested in weapons’ serialnumbers for obvious rea-sons. The numbers may linkcriminals to other crimesand specifically to robberiesthat may have been thesource of the weapons in thefirst place. Of growing sig-nificance is that their iden-tification may lead to pat-terns involving criminal ac-tivities such as straw pur-chases and dealers who maybe supplying guns to orga-nized crime networks. Themere presence of an obliter-ated serial number on acrime gun is a good indicator of traffick-ing because it shows that someone in thechain of possession presumed that thegun will be used in a future crime, mayhave to be discarded and might be re-covered by the police.
Tracing of crime gun serial numbershas been around since serial numbers
first appeared on guns. With respect toThompsons, two of the more famouscases involved the tracking of Thomp-sons supplied to the Irish RepublicanArmy in 1921 and the forensic examina-tion of the Saint Valentine’s Day Massa-cre weapons.
Fast forwarding to this century, a re-
port by the Bureau of Alcohol, Tobaccoand Firearms that analyzed 88,570 tracerequests made by law enforcement offi-cials in 44 communities found that crimeguns are now predominantly handguns(77 percent) and, among handguns,mostly semiautomatic pistols whichalone account for half (50 percent) of all
crime guns traced. Almost10 percent of the traces in-volved handguns with oblit-erated or partially obliter-ated serial numbers. Theproportion of handguns withobliterated serial numbers isnearly twice as large forsemiautomatic pistols (11.3percent) as for revolvers (6.3percent). Obliteration ismore common on guns usedin crimes committed by in-dividuals under 24. Although obliterated se-rial numbers on guns arerelatively common, prosecu-
Amnesty registered 1921 Colt Thompson with obliteratedserial number.
Left: Phoenix gunsmithNelson Ford using spe-cial tooling to removethe barrel of a 1921 ColtThompson.
tions are infrequent. One 2003 studyfound that between 2000 and 2002, Fed-eral prosecutors throughout the nationfiled only 259 cases against individualsin possession of a gun with an obliter-ated serial number. Marc Dupre ofFoCoSS Forensics states, “The lack offollow-through is probably due to thedifficulty prosecutors have in provingthat the individual knowingly obliteratedthe numbers and/or understood its ille-gality (a Federal felony punishable byfive years). Another factor may be thatthe prosecutors typically have a robustshopping list of other crimes whichwould send these individuals to prison.”
Obliteration Methods andRecovery Techniques
The techniques outlined here are com-
monly known and documented in pub-licly available books and articles. Thisinformation was reviewed by practicingfirearms examiners and certain facts notcommonly known are not revealed.
The most common form of serial num-ber removal is surface grinding or fil-ing. Over the past 13 years, Marc Duprehas rarely seen other techniques such aspeening, chiseling, center punching,drilling or welding. Sometimes specificnumbers will be altered by over stamp-ing such as changing a 6 to an 8 or a 1 toa 4. A lot of 8s and 4s are a red flag.
Even though the numbers have beentotally removed, at least visually, thecrystalline structure of the metal under-neath remains unaltered. The serial num-bers can sometimes be recovered bytechniques that differentiate between theunaltered and altered crystalline struc-
ture directly beneath the original num-bers. The most common method is tofirst polish the area and then etch theprepared surface. The altered crystal-line areas etch at a different rate than thesurrounding metal, revealing the origi-nal numbers.
There are a dozen different etching re-agents, depending on the type of metal(e.g., steel, aluminum, brass). There arealso electrochemical, ultrasonic, mag-netic and heat techniques to name a few,and because this is a visual examination,the right type of lighting and photo-graphic enhancements help tremen-dously. Needless to say, there is as muchart as science involved in successful se-rial number recovery.
Marc Dupre states, “Success rates ashigh as 80 percent have been reportedin the literature. Much depends on themethod used to obliterate the number inthe first place; some are more effectivethat others and this is an area we keepwithin the profession, for obvious rea-sons.”
Overlooking the Obvious
Modern weapons typically have the se-rial number in more than one place. Astate police firearms examiner whowished to remain anonymous for this ar-ticle states, “Criminals can be incrediblystupid. I have seen guns such as Glockswith the stamped metal serial numberstrip removed from the frame, but thematching numbers on the barrel and slideunaltered.”
His oddest case of “What were theythinking?” involved Smith & WessonModel 66 stainless steel revolvers.
“When this model firstcame out about 20 yearsago, they were ex-tremely popular andmany were stolen.Someone was profes-sionally welding up the
“Secret” serial number revealed on thereceiver under the forearm of an am-nesty registered 1921 Colt Thompson.
Left: Amnesty regis-tered 1921 Colt Th-ompson with obliter-ated serial numberunder the butt stockon the trigger frame.
78 The Small Arms Review • Vol. 12 No. 9 • June, 2009
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serial numbers visible on the frame andre-stamping new numbers. It was diffi-cult even for forensic examiners to tellthat these were not the original numbers,except for one glaring mistake - the sec-ondary had not been altered near the cyl-inder yoke.”
But even century-old guns can havemultiple serial number locations. Ger-man manufacturers in particular seemedto be obsessed with adding the last fewdigits of the complete number to everylittle part. The classic example is theLuger P08. In fact, all matching num-bers is a major factor for collectableguns.
Some of this numbering is to maintainhand-fitted components or parts matchedfor cosmetic reasons, but in the case ofrifle bolts, for example, it is absolutelycritical to match the correct bolt to thegun to ensure proper headspace. Some-times assembly numbers that have no re-lationship to the serial number are alsoused because a number had yet to be as-signed.
In the case of Thompsons, all of thesefactors came into play. Early Colt guns
were marked on the left side of the re-ceiver and on the underside of the of thetrigger frame. Model 1928 and 1928A1Thompsons were also so marked. SomeM1 and M1A1 Thompsons had triggerframe serial numbers, but that practicewas terminated later in World War II.Specifications after 1943 specified “re-ceiver-only markings.” The reason isobvious for military guns: guns sent backfor repair soon were mismatched.
The first thousand Thompsons had thenumber on the ramp face of the chamberon the barrel. It is sometimes possibleto see this from the extractor cutout inthe receiver. Some specially-orderedguns had serial numbers placed in vis-ible locations such as on the Cutts Com-pensator so that the numbers could beobserved when stored in a gun rack.
There are also matching assemblynumbers placed under both the butt plateand butt stock. Gordon Herigstad, au-thor of Colt Thompson Serial Numbers,is aware of at least one occasion wherethese numbers were also removed eventhough they were just assembly numbers.Its accompanying C drum’s serial num-
ber was obliterated as well.But the only guaranteed way to un-
cover the original serial number wasthrough barrel removal and examinationof the flat area on the receiver under theforearm. Not only were gangsters oblivi-ous to this hidden number, they did nothave the tools or knowledge to reveal it.Indeed, special tools are required to com-plete this operation without marring, orin any way damaging, these valuableguns.
Douglas W. Richardson of Malibu,California, manufactures the requiredbarrel wrench and receiver vice. Theprocess is straightforward as shown bygunsmith Nelson Ford of Phoenix, Ari-zona, on an amnesty-registered gun withan IRS-issued number 6377-D. Theoriginal receiver markings on this gunare peened off and the trigger framenumbers both peened and ground off.Gordon Herigstad correctly predictedbeforehand that the serial number wouldbe under 3,000 because of its “earlymarkings” (i.e., “Full Automatic” and“Semi Automatic” spelled out on the trig-ger frame).
Like many Thompsons of that period,Auto-Ordnance had no specific informa-tion on what is now known to be serialnumber 2976. Colt manufactured thegun but they were a subcontractor toAuto-Ordnance and did not maintaindetailed records on the guns that they didnot own and, of course, the originalAuto-Ordnance is out of business.
The current owner, Charles Olsenjokes, “I was hoping it was sold to a hard-ware store outside Chicago.” Indeed, afew of these stores were the source ofmany of the crime guns of that era. Withthe number revealed, maybe someday thetruth will be known.
History to be Uncovered
Pulling the barrel on a Thompson anddiscovering the original serial number ismore than just an exercise in curiosity.Obviously, the criminals are long sincedead, as are the cases that may have in-volved these guns. Discovering theoriginal serial number is not about put-ting people in jail: it is about uncover-ing lost history. These guns representthe very symbol of a bygone terror thatstill stirs the imagination today.
Gordon Herigstad states, “There wereapproximately 200 of the 495 Thomp-sons - known as the Rorke guns - thatwere destined for the Irish RepublicanArmy. You can usually identify themsince a chisel was used to obliterate theserial numbers. In addition, Peter Von
Frantzius was an armorer who suppliedThompsons with ground-off serial num-bers to gangsters in the Chicago area.Overall, however, there are relativelyfew - possibly a dozen or less - Thomp-sons in museums or in private collectionswith obliterated numbers.”
Some of these still hold secrets yet tobe uncovered. For example, Herigstaddescribes two that he is aware of, “Thereis one in the New York City Police Mu-seum reported to have been used on July1, 1928 by Fred “Killer” Burke to mur-der Frankie (Uale) Yale who ran afoulof Al Capone. It was the first time a Th-ompson was used in New York ganglandwarfare and it is assumed to be directly
linked to Al Capone. The visible serialnumbers are ground off and the only realproof is that key bit of information whichthe museum does not have. I have thenumbers of all the guns bought byCapone and can make the definite link.”
Marc Dupre examined several close-up photographs of this submachine gunand believes that the number could berestored, “You never know until you giveit a try.” Ironically, its value as a pieceof gangster history would actually de-crease if such a restoration were to beattempted. The only way to both pre-serve its significance and trace its ori-gin is to remove the barrel, document thenumber and re-attach the barrel.
Herigstad continues, “Another inter-esting gun is in the Rock Island ArsenalMuseum in Illinois. One of the 17 Th-ompsons in their collection has obliter-ated numbers, and if I pulled the barrel,I could immediately tell if it is also oneof the famous Chicago gangster guns. Itwas acquired locally in 1955 and with-out any descriptive history, but sinceChicago is only 160 miles away, one caneasily speculate there may be a connec-tion. Hopefully someday history will beuncovered on these two Thompsons.”
(Thank you to Chuck Olsen, GordonHerigstad, Marc Dupre and Nelson Fordfor their assistance in the preparationof this article.)
