Unblinking Eye
Pieper New Model 6.35mm Pistol

The Pieper New Model 6.35mm Pistol
Also Known as the Pieper-Delu

by Ed Buffaloe

Félix Delu 6.35mm Pistol - Gerhard Schönbauer

Félix Delu 6.35mm Pistol - Gerhard Schönbauer

Pieper New Model 6.35mm Pistol

Pieper New Model 6.35mm Pistol

The Pieper New Model 6.35mm pistol appeared after World War II, and is said to be the last pistol made by the firm Anciens Etablissements Pieper (A.E.P.). In Pistols of the World, Hogg & Weeks confused the issue of the origin of the Pieper New Model by foolishly stating that it was derived from the Legia pistol of Nicolas Pieper. However, the Legia was a very different design that was made by a different company and is in no way related to the Pieper New Model.

The Pieper New Model is based on the design of the second variation of the Delu pistol. In his 2008 article, Dirk Ziesing appropriately refers to the Pieper New Model as the Pieper-Delu. He relates: “The simplified name ‘Delu’ is a synonym for ‘Fabrique d'armes Delu Félix et Cie’. Its first address was Rue Large Voie 38 in Herstal. Its trademark consisted of the letters ‘Co FD’ in a circle.”

The first variation Delu pistol was patented by Félix Delu in Belgium in 1921. The first variation Delu has an internal hammer, a transfer bar that runs on the right side only, and no grip safety. Both Delu variants have a top-mounted extractor and look nearly identical externally. However, they are completely different internally.  The second varition Delu pistol is quite similar to the 1906 FN Browning: striker-fired, with a Browning-style stirrup-shaped transfer bar, and a grip safety. I am not aware if a patent was ever filed for the second variant of the Delu pistol, and I have been unable to determine exactly what years it was manufactured, but production almost certainly ceased before the beginning of World War II

Pieper New Model 6.35mm Pistol

Pieper New Model 6.35mm Pistol

Michel Druart relates three possibilities for the origin of the Pieper New Model from the Delu:
  1. A.E.P. may have purchased remaining parts from the Delu company and branded them as their own.
  2. A.E.P. may have been the sub-contractor who originally manufactured parts for the Delu company, and they had parts left over that were never delivered or paid for.
  3. Finally, an ex-employee of A.E.P. reported that many of the interlocking companies in Liège, particularly A.E.P. and Fabrique Nationale, transfered machinery between factories during the occupation of Belgium in World War II. After the war, this machinery along with many parts, was returned to the original owners. It may be that A.E.P. acquired the Delu parts at this time.

I do not have an opinion as to which of these scenarios is correct. Dirk Ziesing clearly favors the second, and he may well be correct. The important point is that A.E.P. took leftover Delu parts, designed and manufactured whatever additional parts were needed, and assembled them into the Pieper New Model pistols. Michel Druart, in his book Bayard, displays 1946 dated A.E.P. design drawings for the grip safety lever, the barrel, and the magazine: each had handwritten notes regarding revisions made in 1951.

Pieper New Model 6.35mm Pistol

Pieper New Model 6.35mm Pistol

The Pieper New Model slide has only a single cut on its bottom edge to lock it for disassembly whereas the Delu has a second cut for locking the slide when the safety is engaged. The Delu has a thickened area at the front of the barrel, to make it easier to turn for disassembly, and an oblong hole at the front of the slide to accommodate it. The grip plates for the Pieper New Model appear to be Delu grip plates with the F.D. monogram effaced. The manual safety lever for the Pieper New Model differs from that on the Delu. Pieper redesigned the grip safety to pivot from the bottom and modified the backstrap of the frame accordingly. Both guns feature a magazine safety: a tiny lever extends into the magazine well, at the very top, to lock the sear as soon as the magazine is partially removed.

The Pieper New Model is marked on the left side of the slide in all capital sans-serif characters:




A few early guns have no caliber marking, but most later guns are stamped “6.35 BR” on the left side of the frame ; this mark is often poorly stamped. The right side of the slide is marked in all capital sans-serif characters:


Serial numbers are on the right side and are stamped, on both the frame and the slide, above the trigger. A few guns have no serial number on the slide. Various parts, including the frame, are often stamped with assembly numbers. These are usually on the left bow of the trigger guard, and the right side of the slide, behind the serrations.

Early guns have ten triangular-cut vertical slide serrations on both sides. Some later guns have eight or seven. Some of the late guns appear to have their seven serrations plunge-milled instead of being a triangular-cut.

Extractor Positions on Pieper New Model

Top: Empty Chamber          Bottom: Loaded Chamber

A tiny (less than 1mm deep) groove down the top of the gun serves as a sighting mechanism. There is also a groove down the top of the extractor. A keen eye can detect a loaded chamber by observing the state of the extractor. Without gloves, the loaded chamber state may also be felt with a finger.

I have been unable to locate any advertisements that might indicate when the New Model was marketed. It is marked “MADE IN BELGIUM” on the right side, in English, as if the company intended to market the gun in the U.S. In this regard, Michel Druart relates a story told by a former employee of Pieper that a large number of Pieper New Model pistols were shipped to the U.S., arrived without strikers installed and, hence, were returned.

Serial number 4158 is stamped with the GECO retail mark of the Gustav Genschow company. I have been unable to locate a Geco catalog that includes the Pieper New Model, but the gun clearly saw some distribution in Germany. It could have been legally imported into the U.S. until 1968. We must consider the possibility that the gun received very limited distribution during the last years of A.E.P., as well as the possibility that the final stock of pistols may have been liquidated during the bankruptcy process which, according Michel Druart, lasted from 1954 until 1957.

I have recorded serial numbers from 62 through 8893. At this time I suggest that less than 10,000 were made. There is a purported Pieper New Model that was sold in recent years with the serial number 1. I believe it to be a fake, or to at least have fake markings, or markings that were tampered with, because its proof marks include the Perron which was last used in Liège around 1924. In addition, the right side of the gun is marked “Browning’s Patent” unlike any other known Pieper New Model, and the left side slide inscription is on two lines. Please write to me, if you have a Pieper New Model and send photographs.*

Delu Pistol Field Stripped

Félix Delu 6.35mm Pistol - Gerhard Schönbauer

Pieper New Model Field Stripped

Pieper New Model 6.35mm Pistol

Field Stripping the Pieper New Model (Pieper-Delu)

  1. Make sure the gun is unloaded by removing the magazine, drawing the slide back, and checking to make sure the chamber is empty.
  2. With the empty magazine fully re-inserted, draw the slide all the way back and lock it open using the safety lever.
  3. Remove the magazine.
  4. Turn the barrel 90° clockwise (as you face the front of the pistol).
  5. Release the safety lever, and draw the slide and barrel off the frame, toward the front. The striker will be cocked, and it may interfere with removing the slide. Make certain it does not fly off and get lost.
  6. Rotate the barrel back to its original position, push it back into the slide, and remove it from the bottom.

*Write to edbuffaloe@unblinkingeye.com


  • Druant, Michel. Bayard, les armes et les Machines du Chevalier: Pieper & Cie, 1859-1957. Center for Studies and Research on Arms and Ammunition, Brussels: 2004.
  • Hogg, Ian and Weeks, John. Pistols of the World. Arms & Armour Press, London: 1978.
  • Ziesing, Dirk. “Le pistolet Pieper-Delu.” Gazette des armes № 397, April 2008.

Copyright 2022 by Ed Buffaloe.  All rights reserved.

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