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How to read a fired or unfired cartridge: metric calibre nomenclature (9x19mm Parabellum, 7.62x39mm, 5.56x45mm NATO) vs imperial (.45 ACP, .38 Special, .357 Magnum), SAAMI and CIP specifications, headstamp manufacturer codes (LC for Lake City, RP for Remington, IOF for Indian Ordnance Factory, S+B for Sellier and Bellot), date codes, and military / NATO cross stamps.
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Every cartridge manufactured at an industrial scale carries a permanent identification stamped into the base of the case head before assembly. That headstamp is the forensic examiner's first source-attribution tool. It is not infallible, it can be deliberately defaced, it can be counterfeit, and it can be misread by an inexperienced examiner under field conditions. But when it is intact and correctly interpreted, it compresses hours of elemental analysis and dimensional measurement into a minutes-long preliminary read that narrows the probable origin of a round to a country, a manufacturer, a year, and sometimes a specific production contract.
Understanding the headstamp also requires understanding the calibre-naming systems behind it, because a headstamp is partly a calibre declaration and the naming conventions differ between the metric system used by NATO, European commercial manufacturers, and most of the world outside the United States, and the imperial system that dominates US commercial nomenclature. A round headstamped "9 LUGER" and a round headstamped "9x19" are the same cartridge. A round headstamped ".38 SPL" and a round headstamped ".38 S+W SPECIAL" are also the same cartridge. A round headstamped "7.62x51" and one headstamped ".308 WIN" are dimensionally almost identical but were designed to slightly different pressure specifications. Getting these equivalences and distinctions right is foundational to the preliminary analysis.
This topic covers the metric and imperial naming systems, the SAAMI and CIP specification bodies that define what a given calibre name legally means, and the major manufacturer codes encountered in casework worldwide. The Adam Scott case in the UK (2011) illustrates why headstamp-level source attribution must be accompanied by the full analytical package: a headstamp that points to one production source does not exclude the presence of a physically identical round from a secondary source, and the Scott case showed that contamination of an exhibit with a cartridge bearing a misattributed headstamp propagated a false forensic opinion through multiple court proceedings.
9x19mm means the bullet is 9 mm in diameter and the case is 19 mm long; once that convention is clear, an examiner can decode almost any metric military or European commercial cartridge designation on sight.
The metric calibre system used in NATO standardisation and European commercial production follows a consistent format: bullet diameter in millimetres, a multiplication sign (x), and case length in millimetres. Where a particular cartridge has an established military or civilian name, that name may appear in addition to or instead of the dimensional designation.
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Practice Forensic Ballistics questions9x19mm Parabellum. Bullet diameter 9.01 mm, case length 19.15 mm. Developed by Georg Luger for DWM in 1901 and standardised by NATO as the pistol cartridge for NATO forces. The "Parabellum" name derives from the Latin "si vis pacem, para bellum" (if you want peace, prepare for war), the DWM telegraphic address. On headstamps the round appears as "9 LUGER", "9mm LUGER", "9x19", "9 PARA", "9mm NATO", and various national codes. Maximum average pressure under SAAMI is 35,000 psi (241 MPa); CIP specifies 34,809 psi (240 MPa). SAAMI maximum +P (overpressure commercial) is 38,500 psi. This is the world's most widely issued military and law-enforcement pistol calibre. In India it is the standard for CRPF, NSG, and most state police armed units. In the UK it is the Glock 17 service pistol calibre for the National Police Services Authority. In the US it is the standard military pistol calibre since the M9 in 1985 and the M17 SIG Sauer in 2017.
7.62x39mm. Bullet diameter 7.82 mm (often stated as 7.62 mm), case length 38.60 mm. The AK-47 / AKM cartridge developed by the Soviet Union in 1943 and standardised across Warsaw Pact forces and subsequently across dozens of national armies. The slight discrepancy between the nominal 7.62 designation and the actual bullet diameter (7.82 mm for most commercial and military production) is a persistent source of confusion; it arises because the Soviet design used a groove-diameter specification rather than the land-diameter specification used in Western metric naming. Maximum average pressure is approximately 45,000 psi (310 MPa) under CIP. The 7.62x39mm appears in Indian casework wherever AK-pattern weapons are used or seized, most prominently in Naxalite-affected states (Chhattisgarh, Jharkhand, Odisha) and in Kashmir. Its headstamp usually shows the manufacturer code and a two-digit year; Soviet military production shows a star or hammer-and-sickle symbol. Czech (.vzor 58) and Romanian (PA md. 63) production appears under S+B and respectively coded headstamps.
5.56x45mm NATO. Bullet diameter 5.70 mm, case length 44.70 mm. The US M16 cartridge standardised as the NATO standard assault-rifle calibre by STANAG 4172. SAAMI .223 Remington is dimensionally identical but loaded to slightly lower pressure in early production; modern .223 Rem commercial is nearly equivalent to 5.56 NATO. The SAAMI maximum for .223 Rem is 55,000 psi; the NATO specification uses a piezo measurement method and is approximately equivalent to 55,114 psi for M193 55 gr ball. M855 (SS109 green-tip, 62 gr) is the current NATO standard and appears on headstamps as "SS109", "M855", or the manufacturer's code plus NATO cross. The Indian SIG 716i in 7.62x51 service issue, and the INSAS rifle in 5.56x45mm service, both use NATO-compatible calibres, making NATO-coded headstamps relevant to Indian Army casework.
7.62x51mm NATO vs .308 Winchester. Bullet diameter 7.82 mm, case length 51.18 mm. NATO standardised this calibre in 1954 as the standard rifle and machine-gun cartridge. SAAMI .308 Winchester is dimensionally identical or near-identical but specifies a higher MAP: 62,000 psi vs approximately 58,740 psi for NATO spec. Firing .308 Winchester commercial loads in a marginal 7.62x51 chamber is a recognised case-head-stretch hazard. The round appears in Indian Army service in the Dragunov SVD (7.62x54R is actually the Dragunov calibre, but some Indian snipers operate 7.62x51 platforms), in designated marksman roles, and in CRPF anti-Naxalite operations with PSMGs and self-loading rifles. UK military uses 7.62x51mm NATO in the L96A1 bolt-action sniper rifle and the FN Minimi Para in 7.62 version.
7.62x54mmR. The Russian rimmed rifle cartridge in continuous production since 1891. The "R" suffix denotes the rimmed case. Bullet diameter 7.82 mm, case length 53.72 mm. It is the Mosin-Nagant, SVD Dragunov, and PKM machine-gun calibre and appears in Indian casework wherever Soviet-legacy weaponry is encountered, including armed-forces armouries and Naxalite seizures of military-grade weapons.
The .38 Special fires a bullet that is actually .357 inches in diameter, not .38 inches; understanding why requires a brief history of naming conventions that were set before metrication and were never rationalised.
The US imperial calibre naming system uses decimal fractions of an inch as the primary unit. In theory, ".45 ACP" means the bullet diameter is 0.45 inches and ACP stands for "Automatic Colt Pistol" (the design context). In practice, the relationship between the calibre name and the actual bullet diameter is frequently approximate, historical, or outright misleading.
.45 ACP. Bullet diameter 0.452 inches (11.48 mm), case length 0.898 inches (22.8 mm). The 1904 John Browning design for the Colt Model 1905 and subsequently the M1911 pistol. SAAMI MAP is 21,000 psi (145 MPa), making it a low-pressure, large-diameter cartridge. The .45 ACP is standard in US law enforcement and military units operating 1911-platform weapons, and appears in Indian CRPF and Border Security Force inventories where 1911-pattern pistols were historically issued. On headstamps it appears as ".45 ACP", ".45 AUTO", and ".45 AUTO+P" for overpressure commercial loads.
.38 Special. Bullet diameter 0.357 inches (9.07 mm), case length 1.155 inches (29.3 mm). The nominal ".38" designation derives from the outside diameter of the case, not the bullet; the actual bullet diameter is 0.357 inches, the same as the .357 Magnum bullet. SAAMI MAP is 17,500 psi. The .38 Special was the standard revolver calibre for US and Indian police from approximately 1890 through to the late 1990s. Indian state police forces including the Maharashtra Police and Delhi Police still carry .38 Special revolvers (IOF manufactured) in significant numbers, and the calibre appears frequently in Indian casework involving licensed civilian revolvers.
.357 Magnum. Bullet diameter 0.357 inches (9.07 mm), case length 1.290 inches (32.8 mm). Developed by Elmer Keith and Philip Sharpe in 1934 as a high-velocity revolver cartridge, the .357 Magnum case is 0.135 inches longer than the .38 Special to prevent chamber insertion, but the bullets are dimensionally identical in diameter. SAAMI MAP is 35,000 psi. A .357 Magnum revolver can fire .38 Special cartridges; a .38 Special revolver cannot safely chamber .357 Magnum loads. This interchangeability is a source of calibre-attribution complexity when only fired bullets (without cases) are recovered.
.44 Magnum. Bullet diameter 0.429 inches (10.9 mm), case length 1.285 inches (32.6 mm). SAAMI MAP is 36,000 psi. The Dirty Harry calibre of film fame, the .44 Magnum is a high-velocity revolver cartridge with significant penetration characteristics, used in hunting and in some law-enforcement sidearms.
.50 BMG (12.7x99mm NATO). Bullet diameter 0.510 inches (12.96 mm), case length 3.91 inches (99.3 mm). The heavy machine-gun and long-range anti-materiel rifle calibre developed in 1921. SAAMI MAP is 54,000 psi. In calibre naming this is a case where the imperial designation (.50 BMG, Browning Machine Gun) and the NATO metric designation (12.7x99mm) both appear on headstamps; LC (Lake City) production shows "12.7x99" on NATO-contract rounds and ".50 BMG" on US domestic production.
A cartridge that is within SAAMI tolerances may still be out of CIP tolerances for the same nominal calibre, and vice versa; the forensic examiner who understands this avoids attributing a case-head failure to a defective cartridge when the real cause was cross-specification incompatibility.
SAAMI (Sporting Arms and Ammunition Manufacturers' Institute) is a voluntary US trade association that has published official chamber and cartridge dimensional specifications and maximum average pressure (MAP) standards since 1926. Membership includes all major US ammunition producers (Federal Cartridge, Remington Arms, Winchester Olin, CCI/Speer, Hornady Manufacturing) and all major US firearm manufacturers. SAAMI specifications are referenced in US product liability litigation, ATF ballistic evaluation protocols, and FBI Laboratory technical procedures.
CIP (Commission Internationale Permanente pour l'Epreuve des Armes a Feu Portatives) is the European intergovernmental proof authority. It was established by an 1914 treaty and currently has contracting states including Germany, France, Belgium, Italy, Spain, Czech Republic, Austria, UK, Finland, Hungary, and others. CIP proof marks (the crown-over-letters national mark on UK-proof weapons, the octagonal CIP oval on European commercial weapons) are legally required on weapons sold in CIP member states. CIP cartridge and chamber specifications govern all ammunition sold in CIP countries. India is not a CIP member state, but Indian Ordnance Factory production is designed to NATO STANAG specifications for military calibres and to IOF/DRDO internal specifications for police calibres that often reference CIP dimensions.
Key SAAMI-CIP specification differences relevant to casework:
For the forensic examiner, the SAAMI/CIP distinction is most frequently relevant when a case shows signs of high-pressure firing (primer flow, case-body expansion, case-head thickness change) and the question is whether the cartridge itself was within specification or whether the chamber it was fired in was the mismatch. A CIP-spec cartridge in a SAAMI-spec chamber designed for the same nominal calibre may produce different pressure traces, and this matters when a shooting-incident reconstruction hinges on whether the weapon was mechanically defective.
A headstamp is not a guarantee of origin; it is a production declaration that a manufacturer applied at the time of case manufacturing, and its evidentiary value increases substantially when confirmed by metallurgical analysis.
The headstamp on a centrefire cartridge case is stamped into the base during case manufacture, before the case is loaded. It typically occupies positions on a clock-face analogy: the manufacturer code at 12 o'clock, the calibre designation at 6 o'clock, a year or date code at 3 or 9 o'clock, and a lot or batch number in the remaining positions. Military cartridges often additionally display a NATO cross, a national proof mark, or a contract number. The exact layout varies by manufacturer and by era.
US military and commercial codes. Lake City Army Ammunition Plant (Independence, Missouri), the US government's primary manufacturer of military small-arms ammunition, headstamps its production "LC". Lake City production is used across US Army, Marine Corps, Navy, and Special Operations contracts. Federal Cartridge Company (now Federal Premium, part of Vista Outdoor) uses "FC" or "Federal" on commercial production. Winchester-Olin uses "W-W", "WIN", or "WCC" (Winchester Cartridge Company, an older mark found on military contracts). Remington Arms / Remington Peters uses "RP" or "R-P". CCI (Cascade Cartridge Inc., part of Speer/Vista Outdoor) uses "CCI" on its commercial lines. Speer (also part of Vista Outdoor) uses "SPEER". Hornady uses "HORNADY" or "HDY".
European producer codes. S+B (Sellier and Bellot, Czech Republic, founded 1825, now part of the CBC Group) uses "S&B" or "S+B" and is one of the most widely distributed European commercial producers globally; S+B headstamps appear in casework across India, the UK, and the US in both commercial and military-contract configurations. GECO (Gustav Genschow und Co., Germany, now part of Ruag) uses "GECO" and was historically the standard headstamp on much West German military-contract production. Fiocchi (Italy) uses "FIOCCHI" or "GFL" (Giulio Fiocchi Lecco). RWS (Rheinisch-Westfalische Sprengstoff, Germany, now Ruag) uses "RWS". PPU (Prvi Partizan, Serbia) uses "PPU" and is a major supplier to Eastern European military surplus and commercial markets worldwide. MFS (Magyar Cartridge Factory, Hungary) uses "MFS". IMI (Israeli Military Industries, now IWI / Elbit) uses "IMI" or shows just the Hebrew letter mem and the year.
Indian Ordnance Factory (IOF) codes. IOF Khadki (Pune, Maharashtra, also known historically as Kirkee Ammunition Factory) headstamps its production with "IOF" and a two-digit year. IOF is the primary producer of 9x19mm for CRPF and NSG, 7.62x51mm NATO for Indian Army long-gun use, and .38 Special for state police revolvers. Some earlier IOF production from the Ordnance Factory Board (OFB, now Advanced Weapons and Equipment India Limited after the 2021 corporatisation) uses a distinctive font and proof circle that distinguishes it from commercial ammunition of the same calibre. IOF headstamped cases appear in a significant proportion of Indian police-casework scenes where licensed or government-issue weapons are involved.
UK codes. Kynoch (Birmingham, historically the UK's primary military cartridge manufacturer, now ceased trading) used "K" or "KYNOCH" in an oval. RG (Radway Green, the UK government's Royal Ordnance Factories facility, later BAE Systems) uses "RG" with a two-digit year and appears on virtually all UK military-issue 9x19mm Parabellum (L13A1) and 7.62x51mm NATO (L2A2) production. "KF" on older British military headstamps stands for Kynoch-Fiocchi (a joint-venture arrangement). Fiocchi UK production is separate from RG.
Military cross stamp. NATO-standardised military production for member states typically carries a circle with a cross (the NATO standardisation mark), confirming that the round meets STANAG specifications. This cross appears on LC, WCC, RG, S+B, and many other manufacturer headstamps on NATO-contract lots and is the simplest way to identify a military-specification round regardless of nation of origin.
The 2011 Adam Scott contamination case showed that a headstamp that looks like production evidence can be a transferred case from a different exhibit, and that a forensic opinion built on visual headstamp identification alone is fragile.
In 2011, Adam Scott was charged in the UK with rape, based in part on forensic evidence that included a DNA profile from a sexual assault reference kit. The subsequent investigation by the Forensic Science Service (then still operating before its 2012 closure) and the review ordered by the Crown Prosecution Service revealed that the DNA evidence had been cross-contaminated in the laboratory: a swab from a previous, entirely unrelated case had contaminated the Scott exhibit, producing a false-match DNA profile that was erroneously attributed to Scott.
The relevance to headstamp identification is structural rather than literal. The Scott case does not involve ammunition, but its underlying mechanism applies directly to any forensic identification technique that relies on a single categorical marker (in that case, a DNA profile; in ammunition examination, a headstamp) without corroborating physical analysis. A headstamp that reads "IOF 9mm" on a case found at an Indian crime scene confirms that the case was manufactured at Indian Ordnance Factory and is in 9x19mm calibre. It does not confirm that the case was fired at that scene rather than introduced from a separate source. It does not confirm that the primer, propellant, and projectile in the case at time of examination are original to the IOF manufacturing lot. And if the case has been re-primed (a Boxer-to-Boxer transfer), the headstamp carries the original manufacturing identity while the primer is a replacement.
The correct sequence for headstamp-based source attribution in casework is: (1) photographic and dimensional documentation of the headstamp under the comparison microscope; (2) case-head elemental analysis (XRF or SEM-EDS) to confirm the case material is consistent with the claimed production source; (3) primer-pocket architecture check (Berdan vs Boxer) to confirm consistency with the attributed production source; (4) primer-sealant colour documentation; (5) physical comparison of case dimensions against the SAAMI or CIP specification for the headstamp-declared calibre.
India-specific context. The Operation Black Tornado post-incident investigation (the NSG assault on the Oberoi and Nariman House during the Mumbai 26/11 attacks, November 2008) involved recovery of significant quantities of 7.62x39mm AK-pattern ammunition and fired cases. Headstamp analysis attributed the bulk production to Eastern European and Chinese military sources. The forensic report noted that the consistent headstamp across scenes was confirmatory of a single supply chain but required case metallurgy to exclude the possibility of locally sourced cases with headstamp replications. The UK NABIS (National Ballistics Intelligence Service) applies a structurally identical multi-layer analysis when attributing crime-gun ammunition to specific production contracts.
Czech and Serbian production in global casework. S+B (Sellier and Bellot) and PPU (Prvi Partizan) headstamps appear in casework on every continent. S+B 9x19mm production is exported commercially to the US, UK, Australia, India, and most of sub-Saharan Africa. PPU 7.62x39mm surplus production is available in volume in North American commercial markets and appears in crime-gun submissions to the ATF. When either headstamp appears in a case, the examiner should document it as commercial European production in the first instance and then verify whether the dimensional specifications are within CIP or SAAMI tolerances for the declared calibre.
Headstamp examination has a defined sequence because reading the headstamp first without documenting its condition can destroy the probative value of the subsequent microscopic examination.
The systematic examination of a cartridge case at an accredited firearms laboratory follows a protocol that treats headstamp examination as one step in a documented sequence, not as a preliminary shortcut that replaces physical measurement.
Step 1: Photography before handling. The case is photographed in place (as received) before any handling that could alter marks. A metric scale is included. The base of the case is photographed square-on to the headstamp with sufficient magnification (typically 10x) to resolve all headstamp text characters.
Step 2: Loupe or low-power microscope examination. The headstamp text, primer-pocket architecture, primer sealant condition, and rim geometry are all documented using a hand loupe (10x minimum) or a low-power comparison microscope at this stage. Each character of the manufacturer code, calibre designation, year code, and any lot or NATO cross is recorded.
Step 3: Case-head condition documentation. Before the primer is removed (if examination requires it), the firing-pin impression, breech-face marks, and primer cup condition are documented. These are discussed in the Module 6 comparison-microscopy topics.
Step 4: Calibre measurement. The case body, case head, and case mouth are measured with calibrated micrometers or a digital calliper to verify against the SAAMI or CIP specification for the headstamp-declared calibre.
Step 5: Reference database query. The examiner queries the headstamp code against the General Rifling Characteristics (GRC) database maintained by the FBI Laboratory's Firearms and Toolmarks Unit (which includes an ammunition component section), the UK NABIS headstamp reference collection, the INTERPOL Ballistic Information Network headstamp directory, or the AFTE (Association of Firearm and Toolmark Examiners) reference database. Where a match is found, the production lot, country of origin, and known user-state or commercial distribution record is appended to the case report.
CFSL India practice. The Central Forensic Science Laboratories at Chandigarh, Hyderabad, Kolkata, and Mumbai maintain national-level reference collections of headstamps from Indian and international production. Cases submitted through state FSLs under CrPC (now BNSS) Section 293 expert report provisions are examined against these reference collections. IOF production identification is effectively straightforward given the controlled domestic production environment; the challenge for Indian CFSL laboratories is correctly identifying surplus military ammunition imported through grey-market channels, which may carry authentic foreign headstamps but be loaded with non-standard propellant or projectile components.
| Headstamp code | Manufacturer | Country | Notes |
|---|---|---|---|
| LC | Lake City Army Ammunition Plant | USA | US military primary production; NATO-contract production carries NATO cross |
| FC / Federal | Federal Cartridge / Federal Premium | USA | Commercial production; Federal HST, Gold Medal Match, American Eagle lines |
| WCC / W-W | Winchester Cartridge Co / Winchester-Olin | USA | Commercial and military-contract; WCC on military lots |
| RP / R-P | Remington Peters / Remington Arms | USA |
A 9x19mm Parabellum cartridge case headstamped 'IOF 9MM' with a red primer sealant ring is recovered from an Indian crime scene. The examiner confirms the Berdan primer pocket architecture. Which combination of characteristics is most consistent with Indian Ordnance Factory production for police service?
| Commercial production; RP is older mark, R-P is modern |
| IOF | Indian Ordnance Factory, Khadki (Pune) | India | Military and police production; 9mm, .38 SPL, 7.62x51 NATO |
| S+B / S&B | Sellier and Bellot (CBC Group) | Czech Republic | Major European export producer; commercial and military |
| GECO | Gustav Genschow / Ruag | Germany | Commercial and historically military-contract German production |
| PPU | Prvi Partizan | Serbia | Major Balkan export producer; 7.62x39mm surplus widely distributed |
| IMI | Israeli Military Industries (IWI / Elbit) | Israel | Military and commercial; 9mm, 5.56, 7.62x51 |
| RG | Radway Green / BAE Systems | UK | UK military primary production; L13A1 9mm, L2A2 7.62x51 NATO |
| MFS | Magyar Cartridge Factory | Hungary | Hungarian commercial and surplus production |
| PMC | Poongsan Corporation | South Korea | Commercial and military export; .45 ACP, 9mm, 5.56, 7.62 NATO |