Michael Zeleny (larvatus) wrote,
Michael Zeleny

sig p210 heavy frame development ii

Continued from here.

The slides and frames of the original P210 were machined from impression-die steel forgings weighing 2.320kg (5.1lbs). The finished frame weighed in at 0.330kg (0.73lbs) after undergoing 107 machining operations (see Doebeli, p. 98 and Vetter, p. 180). Between 1983 and 1984, SIG introduced a new production series of the P210, switched over to Computerized Numerical Control (CNC) manufacture of major components. Starting gradually with the serial number P97601 and continuing with pistols serial numbered from P300001, frames milled out of 35mm steel plate stock replaced frames milled out of forgings. The CNC frame production run is distinguishable by an angled and faceted, rather than a radiused, transition from the dustcover to the rail housing:

    Frame cross-section profiles: (1) Petter Mod. 1, No. 4, 9mm; (2) Petter Mod. 2, No. 6009; (3) SP47/8, pre-production, Nos. 6031-6060; 4) SP47/8, No. 6383; (5) P210-1; (6) P210-5 prototype; (7) heavy frame; (8) CNC machined.
click on the picture for higher resolution
It is undisputed among metallurgists that forgings have less surface porosity, finer grain structure, higher tensile strength, better fatigue life, and greater ductility, than castings:
Conventional closed-die forging begins with a simple hot-rolled shape and utilizes reheating and working to progressively convert it into a more complex geometry.The shape of the various cavities controls the flow of material, and the flow, in turn, imparts the oriented structure discussed in Chapter 16. (Grain flow that follows the external contour of the component is in the crack-arrestor orientation, improving strength, ductility, and resistance to impact and fatigue.) Through forging, we can also control the size and shape of various cross sections, so the metal can be distributed as needed to resist the applied loads.Couple these factors with a fine recrystallized grain structure (hotworking) and the absence of voids (compressive forming stresses),and we see why forgings often have about 20% higher strength-to-weight ratios compared with cast or machined parts of the same material.
— J.T. Black and Ronald A. Kohser, DeGarmo’s Materials and Processes in Manufacturing, Tenth Edition, Wiley, 2008, pp. 392-393
The milspec parts of the P210 firing system, including the hammer action housing, the sear, the double pull lever, and the hammer, which also started out as milled out of forgings and deep hardened, underwent a parallel transition, wherein all but the hammer were gradually replaced by cast or MIM counterparts between 1984 and 2000. As with all MIM components, these parts are superficially case hardened. They are therefore unsuitable for hand fitting that is liable to cut through the hardening and expose soft core metal in the working surfaces. This image is taken from Armbruster, p. 193:

    Double pull levers used during the SIG P210 production runs. Nos. 1-4 are milled and hardened. From No. 2 the area between the anterior and posterior pressure ridges was reinforced by adding material. No. 5 is the latest version, produced by metal injection molding.
click on the picture for higher resolution

Given the standard forged P210 frame’s documented, howsoever infrequent, propensity to break under heavy loads, switching from milled forgings to CNC machined steel plate might have resulted in diminishing the tensile strength and resistance to impact and fatigue of the Neuhausen pistol’s frame. However, standard CNC frames were configured with reinforcements under the rail housing, which made them more robust than their forged predecessors. Thus standard CNC frames are able to withstand not only the use of Swiss military PP41 ammunition for which they were optimized, but also 9mm NATo ammunition that tended to fracture their predecessors built with standard forged frame. (I owe this information to a personal communication by Hubert Brutsche, formerly a gunsmith employed by SIG.)

Additionally, SIG continued to release heavy frame variants within its CNC machined frame production run. Thus between 1987 and 1990, SIG delivered 105 more P210-5 marked Heavy Frame pistols, serial numbered from P309501 and P309605. They featured a choice between 150 mm and 180 mm barrels in the 50 pistol serial number range between P309521 and P309570, mainly chambered in 9mm Para, as well as “false” P210-5-marked variants fitted with 120mm barrels, such as the 100 piece series numbered between P306501-P306605 and between P309550-P309650. Due to the lack of availability of slides correctly labeled with P210-6 and an excess of P210-5 slides, these pistols were delivered so marked by the factory in order to meet the demands of the shooters in a timely manner. Another 50-pistol P210-5 Heavy Frame batch was produced in 1993, serial numbered between P314466-2 and P314515-2. In 1995, 40 more P210-5 Heavy Frame pistols were serial numbered from P315821 to P315860. A Heavy Frame pistol serial numbered P316550, fitted with a 120 mm barrel and marked P210-6 Target, is representative of subsequent production. Other CNC guns with heavy frames have been published and observed serial numbered P309660, P309665, P309691, P312382, P316550, P316900, P317066, P319330, P319345, P319569, P319703, P320138, P320156, P320198, P321108, P323098, P323121, and P323550.

The swan song of SIG was the P210-8 model variant, notable for its “American style” button magazine catch on the left hand side of the frame. The first series production firearm to be equipped with a detachable box magazine was the Borchardt C93 pistol, released in 1893. Borchardt’s design was anticipated by James Paris Lee in his patent number US221328A of 4 November 1879 that described a “magazine or cartridge-holder” fitted to a rifle, and made detachable by operating a swinging lever catch in its rear. Whereas all of John Moses Browning early production pistol designs, starting with the 1899 and 1900 pistols described in his patent number US621747 of 31 March 1899, used a magazine release placed in the heel of the grip frame. Browning’s first series production use of the Borchardt-style button magazine catch appeared in the Colt M1911, as protected by the design of “magazine mountings, e.g. for locking the magazine in the gun” described in his patent number US984519A of 17 February 1910, Borchardt’s prior art notwithstanding. This system, as carried over from its C93 Borchard progenitor, was employed by Georg Luger in his Model 1900 handgun that on on 4 April 1901 became the first autopistol to be adopted into military service in a cutting edge choice by the Swiss Army. Although the SIG P49 reverted to the heel magazine catch judged to be more secure as a mode of its retention, popular fashion in service sidearms, driven by the Colt M1911 and its imitators, continued to favor its button magazine catch on the side of the frame. This was identified as the key feature of a special run of 30 pistols commissioned from SIG in the late 1990s by a head of a small Persian Gulf state.

To fulfill this order, SIG at first approached Kurt Tschofen of Waffen-Oschatz. Tschofen prototyped it as a set serial numbered P316900, including both a standard and a heavy frame, along with upper assemblies in .22LR and 9mm Para, all numbered en suite. The magazine retention was based on the S&W M39 magazine catch, as previously retrofitted by Waffen Oschatz to their customers’ stock SIG P210 pistols on an individual order basis. Tschofen fitted the original SIG rear micrometer sight to original SIG soft slides that were milled down to install it much lower, whereupon all altered parts went back to SIG Neuhausen and Hämmerli in Lenzburg and Tiengen for heat-treating and the final assembly and finish of the guns. SIG-Oschatz pistols were initially built on a mix of standard and heavy frames serial numbered from P319800 to P319899 and from P320400 to P320499. They retailed from 1998 to 2000 designated by SIG as SIG P210-6 Sport, when fitted with a 120mm barrel, and as SIG P210-5 Sport, when fitted with with a 150mm barrel tipped with a barrel weight based on the 1997 patent by the German gunsmith Harald Berty. They were fitted with Karl Nill walnut grips of Sport, Combat, and Match patterns. Additional options included beavertails and extended magazine floorplates made by Karl Nill. Subsequent deliveries from Waffen Oschatz to SIG, included at least 80 additional standard frame SIG P210-6 Sport pistols numbered from P321800 to P321839, and their heavy frame likes numbered from P321840 to P321879.

SIG P210-8 pistol serial number P319366 from the first series by Léon Crottet.
Built on a CNC milled frame with a lanyard loop.
Fitted with an extended safety lever, lateral magazine catch, and a magazine with a standard floorplate.
Featuring a dot front sight matched with a low mounted LPA micrometer rear sight.

Notwithstanding successful commercialization of the SIG P210-6 Sport and SIG P210-5 Sport variants, the Middle Eastern customer that inspired their development, rejected their delivery for failing his function and reliability tests in their magazine retention design. To fulfill his order, SIG turned to the Swiss gunsmith Léon Crottet of Waffen Crottet, renowned for his fully operational miniature replicas of classic firearms. As a contition of fulfilling it, Crottet insisted on receiving a special model designation. Thus the P210-8 became the final pistol model variant to be officially designated in the SIG catalog. The first 40 pistols so designated, 30 of which were delivered to the Persian Gulf Emir whose order inspired this development, were numbered from P319360 to P319399, as distinguished by an upside-down “8” rollmark, and featuring the traditional lanyard ring on the grip frame and magazines fitted with a standard stamped steel floorplate. Their magazine release buttons and safety levers had been originally developed by Crottet in the 1970s for retrofitting to his customers’ P210 pistols. The rear sight mounts on the P210-8 slides were lowered and fitted with Italian LPA sights. A second series of 120 Crottet P210-8 followed, numbered from P321000 to P321119, featuring low mounted LPA sights, omitting the lanyard ring on the grip frame, and adding extended magazine floorplates of his own design. Next came a series of 70 Crottet P210-8 pistols, 30 featuring low mounted LPA sights and numbered from P321130 to P321159, followed by 40 featuring bar and dot contrast fixed sights fitted in the standard dovetail and numbered from P321160 to P321199. Next Crottet delivered a batch of P210-8 pistols to SIGARMS Inc in Exeter, U.S.A. Observed serial numbers include P321003, P321021, P321070 (chromed frame), P321054, P321055 (chromed frame), consecutive numbers from P321059 to P321078, P321057, P321087 (double numbered with a chromed frame P210-8 pistol), P321106, P321118,P321122, P321154, P321194 (extended beavertail curved upwards), P321618, P321650, P321653, and the last SIG P210 ever made, numbered P800000.

SIG P210-8 pistol serial number P321106 by Léon Crottet.
Built on a CNC milled frame lacking a lanyard loop.
Fitted with an extended safety lever, lateral magazine catch, and a magazine with a heavy floorplate.
Featuring a dot front sight matched with a low mounted LPA micrometer rear sight.
Sold on 30 April 2016 for CHF9,500 at Swiss Auction Center GmbH in Haerkingen, Switzerland.

SIG P210-8 pistol serial number P321194 by Léon Crottet.
Built on a CNC milled frame with a checkered front grip strap and lacking a lanyard loop.
Fitted with an extended safety lever, lateral magazine catch, and a magazine with a heavy floorplate.
Featuring fixed sights mounted in standard dovetails and an extended and sculpted weld-on grip tang.
Sold on 30 April 2016 for CHF15,500 at Swiss Auction Center GmbH in Haerkingen, Switzerland.

The last Crottet P210-8 pistol was numbered P8000000, as the final echt SIG firearm to be made, in a 2002 delivery of a 1999 special order by a Swiss SIG customer, last seen advertised for sale in January 2017 for CHF 18,000.00.

SIG P210-8 pistol serial number P800000 by Léon Crottet.
Built on a CNC milled frame without a lanyard loop.
Fitted with an extended safety lever, lateral magazine catch, and a magazine with a heavy floorplate.
Featuring fixed sights mounted in standard dovetails.

All Crottet P210-8 pistols were built on the heavy frame. The standard configuration featured Karl Nill walnut grips with a stippled finish, with an option to substitute Waffen Wyss HI-Grips molded from black polymer, either symmetrical or fitted with a thumb rest for the right hand. In so far as the proprietary side magazine catch used by Léon Crottet differs from the S&W M39 magazine catch fitted to Waffen Oschatz-made pistols, their magazines have different cutouts and are not interchangeable. The list price of the Léon Crottet SIG P210-8 variant marketed in the United States was $4,289.00, when the basic P210-2 listed at $1,680.00 and the P210-5 and P210-6, at $2,325.00 and $2,089.00, respectively.

In 1997, the firearms division of SIG was restructured and renamed SIG Arms Hämmerli AG. It was downsized in 2000, upon the expiration of government contracts for the manufacture of the Swiss assault rifle, when SIG transformed its firearm production facilities into a distribution center, eventually to rebrand itself as an industrial holding company best known for its beverage packaging products. On 30 November 2000 the corporate parent SIG divested itself of SIG Arms, whereupon two German investors, Michael Lüke and Thomas Ortmeier, operating under the corporate identity of L & O Holding, purchased the arms section of SIG Neuhausen, renaming it Swiss Arms Neuhausen (SAN). This sale did not include the trademark thitherto applied to the SIG firearms, whose oval rollmark thenceforth disappeared from the P210 slides. SAN operated out of former SIG premises in Neuhausen am Rheinfall, employing most of their remaining staff. In the wake of this corporate upheaval, Hämmerli of Lenzburg, responsible for the production of all P210 variants save for very early Neuhausen issues, reacquired a measure of independence, reverting to its original name, Hämmerli AG. In July of 2003 it relocated to Neuhausen and merged with the arms manufacture operated by Lüke and Ortmeier, then known as SAN Swiss Arms AG. Both companies now had the same owners and managing director, but claimed to operate autonomously. Hämmerli continued to collaborate with Sauer, e.g. by supplying its aluminum stock supporting the Sauer barreled action of the 205 System. In the P210 production as continued by SAN without the SIG brand, heavy frames are found serial numbered P325122, P325204, P325241, P325289, P325349, P325364, P325396, P325690, P325706, P330691, P330710, P330711, P330820, and P330938. SAN also produced a derivative of the SIG P210-8, characterized by an extended tang and a redesigned lateral mag button release that omitted the right hand side frame button cutout, as the P210-6S and P210-5LS (long slide) variants, numbering around 200 each. Some teething problems ensued, with the hammer hitting the tang in recoil cycle, and the omitted magazine safety causing the trigger rod standing proud of the bottom of the breech block to interfere with disassembly following the removal of the magazine from the pistol. The main problem with this redesign was the interference of the magazine release button with the trigger stop, with the rear end of the trigger stop tending to block the magazine release. All P210-8 variants made by SIG and finished by Léon Crottet or Waffen Oschatz, and all P210-6S and P210-5LS variants made by its Swiss Arms Neuhausen (SAN) successors with a lateral magazine catch, also had the heavy frame.

It can be seen that heavy frame pistol production became much more frequent with the passage of time, growing from 278 forged heavy frame pistols documented by Doebeli, to an estimated 2,000 heavy frame pistols in the subsequent CNC milled frame production. Even so, their sum total is less than one per cent of the total Swiss P210 military, constabulary, and commercial variants numbering around 240,000.

But all this was not to last. On 24 January 2006, Swiss Arms Neuhausen put out a notice of terminating the production of the P210 pistol and SHR970 rifles. The hiatus lasted until 2010, when Sauer & Sohn, another member of the Lüke & Ortmeier Gruppe, located in Eckenförde in Germany, and previously known for its collaboration with SIG in making the P220 pistol and its derivatives, announced the resumption of P210 production as its P210 Legend, whose serial numbering appears to start around P334378. All of these German produced pistols feature heavy frames. But theirs is another story.


Erwin Armbruster & Werner Kessler, Begegnungen mit einer Legende — SIG SP 47/8 / P 210, Kessler Waffen AG, 2007

H.P. Doebeli, Die SIG Pistolen, Motorbuch Verlag, 1981, ISBN 3-87943-739-4

Robert R. Field, “SIG P210-5 Heavy Frame: Präzise Rarität”, Deutsches Waffen-Journal, Februar 1992, pp. 192-197

“Porträt von Léon Crottet”, «SchiessenSchweiz», dem offiziellen Verbandsorgan des Schweizer Schiesssportverbandes, Dezember 2012, pp. 54-55

Lorenz Vetter, Das grosse Buch der SIG-Pistolen, Motorbuch Verlag/Verlag Stocker-Schmid, 1995, ISBN 3-7276-7123-8

“Waffengeschichte: Léon Crottet und seine Weiterentwicklung der SIG P 210-8”, Schweizer Waffen-Magazin, Januar 2015

— The author thanks Daniel Ott and Marco Besana for valuable discussion.

Tags: german, guns, p210, research, sig, swiss

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