Key Takeaways
- Janz interchangeable-caliber sets can only be built on the EM or E frame; the MA frame, chambered for .460 and .500 S&W, is offered in fixed caliber only.
- German proof law classes exchange barrels and interchangeable revolver cylinders as the highest-stressed parts, so each carries its own proof mark, and separately proved parts also carry their own place and year marks.
- Janz lists the parts of a set one by one, giving caliber, barrel length, shroud treatment, cylinder fluting, and finish for each assembly. Auction records describe at least two different factory case styles, an aluminum case and a wood-veneered metal case.
A Janz interchangeable-caliber set is one revolver frame supplied with more than one barrel and cylinder. Janz-Präzisionstechnik GmbH of Malente, Germany, describes the system, sold as the Type S and Type EM-S, as a single base frame that can be converted to every caliber it offers, from .22 LR to .454 Casull, with barrel lengths from 2 1/2 to 12 inches. The factory says caliber changes are made without tools, in seconds. [1] Because the components of a set are made, proved, and marked as separate parts, a cased Janz set is best read as a group of individually documented objects rather than as a single gun.
The Maker
The firm behind the revolvers is JTL, short for Janz Technik und Labor. Founded in Kiel in 1935 as a precision-mechanics workshop, it is now based in Malente, near Kiel. Its main business remains analytical instruments for the dairy industry. [2] In the 1990s, the company made firearm parts for Korth of Ratzeburg. After Korth’s insolvency, Janz was left with Korth revolver and pistol parts, unpaid invoices, manufacturing know-how, and a license to make firearms. [3]
The factory’s own account sets out the chronology:
- In 1997 the company decided to build its own revolver and hired René Ganz, whom it describes as Willi Korth’s last apprentice.
- A complete drawing set was finished at the end of 1997, and the first hand-built sample followed in early 1998.
- A first prototype in .44 Magnum was finished at the end of 1998 and passed official proof.
- A second prototype, in .454 Casull on an enlarged frame, was completed and proved in 1999.
- The changeover to series production, at ten revolvers a month, ran from late 1999 to March 2000.
The original specification planned a small series of no more than 100 revolvers a year. The company lists Uwe Janz and René Ganz, both master gunsmiths, as responsible for the revolvers’ precision. [3]
The parent firm’s initials also appear in model names. The Blue Book of Gun Values records that the Type E was originally called the JTL-E and lists a Type S (JTL-S) with interchangeable barrels and cylinders. [4] The factory specification describes the cylinder release as a gilded “JTL” ball on the right side and lists grips optionally secured with a JTL emblem. [1]
Which Frames Can Form a Set
Janz builds three frame sizes:
- EM: .22 LR to .44 Magnum, available as an interchangeable system.
- E: .22 LR to .454 Casull, available as an interchangeable system.
- MA: .460 and .500 S&W, fixed caliber only.
A multi-caliber set can therefore only be built on the EM or E frame. [5]
Factory cylinder capacities are eight (or seven) for .22 LR, seven (or six) for .357 Magnum, six (or five) for .44 Magnum, and five for .454 Casull. Trigger weight can be adjusted from outside, from 800 to 2,000 grams single action and 3,000 to 6,000 grams double action, read against a plus/minus scale. Nill wood grips are standard. [1]
How a Set Is Specified
The factory’s stock list dated March 2025 shows how Janz itself describes a set: component by component. One Type EM-S entry includes:
- A .44 Magnum frame assembly with a 10-inch barrel, a pierced shroud with wood inlays, and the “TIN Paket 2” option package.
- An additional .44 Magnum barrel of 2 1/2 inches.
- A .357 Magnum barrel and 6-inch fluted cylinder, plus an extra 2 1/2-inch barrel.
- A .327 Federal Magnum barrel and 6-inch cylinder, with an extra 2 1/2-inch barrel. [6]
The list separates caliber, barrel length, shroud treatment, cylinder fluting, and finish for each assembly. A complete set should correspond to such a component list.
Proof Marks on Each Component
German proof law treats the parts of a set individually. The Beschussgesetz defines “highest-stressed parts” (höchstbeanspruchte Teile) as those exposed to gas pressure. These explicitly include exchange barrels made to fit a given model without refitting, and revolver cylinders that can be changed on a given model without refitting. [7]
The Beschussverordnung requires the official proof mark on each such part. It also requires a place mark and a year mark on a highest-stressed part. The year mark is the last two digits of the year, optionally followed by the month, and on application the digits may be coded as letters (A = 0 through K = 9). Each highest-stressed part submitted for proof on its own must carry the proof mark, place mark, and year mark. [8] A barrel or cylinder proved separately therefore carries its own date of proof.
Germany replaced the federal eagle with the C.I.P. mark on its proof stamps in 2022, while keeping the letter N for nitro-powder proof. [9] A set assembled across that change may show both forms of mark on different components.
Cases and Accessories in Auction Records
Two Rock Island Auction Company lot records describe the factory packaging of single-caliber Janz revolvers. The descriptions document these lots only.
The first, Lot 749, was sold on April 13, 2018. It was a .357 Magnum revolver with a 4 1/4-inch slab-sided barrel, a seven-shot fluted cylinder, and a button on the right side of the frame for quick cylinder changes. It came in an aluminum Janz case lined in blue velvet, with an extra checkered target-style grip, seven brass snap caps in a holder, and a tool. [10]
The second, Lot 3612, was sold in Bedford, Texas, on August 17, 2025. It was a fixed-caliber Type EM in .357 Magnum with a 6-inch barrel. The description records:
- A matching numbered crane.
- The “Janz” logo and caliber designation machined into the left barrel flat.
- An importer mark on the underside of the barrel.
- A wood-veneered metal Janz hard case, a Janz screwdriver with two bits stored in the handle, and a manual. [11]
The two lots show two different case styles, so a case’s material alone does not identify a configuration.
For the firm’s Alpha 9 mm pistol prototype, a 2021 all4shooters test listed the supplied equipment: a case with a combination lock, tools for adjusting the sights, trigger weight, and trigger stop, and a factory test target. [12]
Custom Work
Janz offers deep-cut or shadow engraving, with or without inlaid gold wire, and animal motifs to order. [13] At IWA 2018, all4shooters photographed several one-of-one Janz revolvers, including a .44 Magnum with gold inlays. The publication reported a waiting time of about one year and prices of up to 25,000 euros. [14] On a custom set, the factory component list and the proof and year marks on each barrel and cylinder record what was built together.
Frequently Asked Questions
It is a single Janz revolver frame supplied with additional barrels and cylinders in other calibers or barrel lengths. The factory sells the system as the Type S and Type EM-S, covering calibers from .22 LR to .454 Casull and barrel lengths from 2 1/2 to 12 inches.
Janz decided to build its own revolver in 1997, finished the first hand-built sample in early 1998, and completed a .44 Magnum prototype at the end of that year. Series production of ten revolvers a month began between late 1999 and March 2000.
JTL stands for Janz Technik und Labor, the parent company founded in Kiel in 1935. The initials appear in early model names such as JTL-E and JTL-S, on the gilded cylinder-release ball, and on the optional grip emblem.
German law classes exchange barrels and interchangeable revolver cylinders as the highest-stressed parts, and each such part must bear the official proof mark. A part submitted for proof on its own also receives its own place mark and year mark.
One example sold at Rock Island Auction in 2018 came in a blue-velvet-lined aluminum Janz case with an extra grip, seven snap caps, and a tool. Another, sold in 2025, came in a wood-veneered metal Janz hard case with a screwdriver holding two bits in the handle and a manual.
Sources
[1] Janz-Präzisionstechnik GmbH. “Wechselkaliber Revolver Typ S und EM/S.” Janz-Präzisionstechnik GmbH, n.d.
[2] Janz-Präzisionstechnik GmbH. “Die Firma.” Janz-Präzisionstechnik GmbH, n.d.
[3] Janz-Präzisionstechnik GmbH. “Entwicklungs-Etappen des JANZ-Revolvers.” Janz-Präzisionstechnik GmbH, June 2012.
[4] Blue Book Publications. “JANZ GmbH REVOLVERS.” Blue Book of Gun Values, n.d.
[5] Janz-Präzisionstechnik GmbH. “Rahmen EM/E/MA.” Janz-Präzisionstechnik GmbH, n.d.
[6] Janz-Präzisionstechnik GmbH. “Herzlich Willkommen bei Janz Revolver.” Janz-Präzisionstechnik GmbH, March 2025.
[7] Bundesministerium der Justiz and Bundesamt für Justiz. Beschussgesetz (BeschG), § 2 Beschusstechnische Begriffe. Act of October 11, 2002.
[8] Bundesministerium der Justiz and Bundesamt für Justiz. Beschussverordnung (BeschussV), § 9 Aufbringen der Prüfzeichen. Ordinance of July 13, 2006, as amended October 1, 2021.
[9] Eichstädt, Ulrich. “Know-how mit all4shooters: Was Sie über das deutsche Beschussrecht und Ihre Schusswaffen wissen müssen.” all4shooters, VS Medien GmbH, August 27, 2025.
[10] Rock Island Auction Company. “Lot 749: German Double Action Revolver 357 magnum.” Auction Catalog #73, April 13, 2018. Lot description.
[11] Rock Island Auction Company. “Lot 3612: Janz Type EM Precision Revolver in .357 Mag. with Case.” Auction 4095, Bedford, Texas, August 17, 2025. Lot description.
[12] Riegel, Robert. “Janz-Selbstladepistole Alpha: Prototyp in 9 mm Luger mit Drehriegelverschluss, aber Hahnschloss wie beim Revolver.” all4shooters, VS Medien GmbH, September 1, 2021.
[13] Janz-Präzisionstechnik GmbH. “Gravur und Oberflächen-Veredelung.” Janz-Präzisionstechnik GmbH, n.d.
[14] The Team of all4shooters.com. “Janz: very special revolvers made in Germany.” all4shooters, VS Medien GmbH, April 5, 2018.
