Do You Know Your HK’s Parents?



"Gerät 03 diagram from Karl Maier’s notes. Note that the rollers rest on parallel surfaces, so no amount of force pushing back on the bolt can cause it to unlock."



"Diagram of StG-45(M) locking system from von Lossitzer’s notebook. Note here that the rollers rest on angled surfaces, so pushing on the bolt will cause it to unlock."

Stg.45 Gerät 06



Sturmgewehr 45 Gerät 06(H)

" The man responsible for the original concept was Dr. Karl Maier, a Mauser mathematical physicist. After the war Dr. Maier was captured by the Americans and eventually came to the United States as part of 'Project Paperclip,' a program designed to keep German scientists out of the hands of the Russians. In fact, Dr. Maier spent many years working at the Springfield Armory before becoming an independent firearms consultant. Today, Dr. Maier is enjoying a quiet retirement in his native Germany."

The Springfield armory worked on the T-28 rifle,but this was not a Roller delayed blowback abut a Roller Locking mechenism as the one used in the Gerät 03.

























"...In developing the T28 Rifle, Cyril A. Moore sought to design a weapon that could be simple and inexpensive to manufacture. Moore's T28 was made of sheet metal stampings, simplified forgings and brazed assemblies. He was following the philosophy that had dominated German arms development during WWII. The German designers assumed that a weapon could be lost or destroyed before it wore out. Therefore, to cut down the cost of replacement they decided to develop small arms which could be turned out cheaply on punch presses and screw machines. Such weapons could also be made in most small metal shops where such equipment was in use.
The genealogy of the T28 goes back to the final wartime experiments at the Mauserwerke. Several incomplete developmental weapons were discovered by a Technical Team of the Allied Combined Intelligence Objectives Subcommittee (CIOS) when they ransacked the Mauser experimental shops at Oberndorf an Neckar. Samples of these weapons were forwarded to Moore at Springfield. He incorporated elements from two of these weapons into the T28.
A roller lock and two-piece bolt was common to the two Mauser designs. The forward section (bolt-head) contained two vertically mounted roller bearings. These roller lock the bolt when forced into the locking recesser by the tapered protrusion on the rear portion of the bolt (bolt extension). In one of the Mauser rifles, a short tappet piston gave an initial impulse to the bolt extension. As this section of the bolt moved to the rear, the extension ceased its wedging effect, allowing the rollers to be cammed back into the bolt-head. The whole bolt assembly then travelled to the rear propelled partly by the residual pressures in the chamber.
The Armory proceeded with the development of the T28 on a limited scale for nearly four years. A total of 11 T28 rifles were fabricated. These rifles were favorably received by the Aberdeen testing officers. Many of the weaknesses discovered in the early prototypes were corrected in later models. The Aberdeen report concluded that "the T28 has several advantages over present standard equipment but has a number of undesirable features. Further development is necessary in order to reduce malfunctions and the breakage of parts."
Nevertheless, the T28 rifle did not survive the limited budgets. Sometime in the winter of 1950-51, Colonel Rene Studler's office terminated the project so that the development funds could be used elsewhere..."

"r of proposals submitted, Großfuß AG's proved to be the best design by far, employing a unique recoil-operated roller locking mechanism whereas the two competing designs used a gas-actuated system.[3] Interestingly, the company had no prior experience in weapons manufacture, specializing in pressed and stamped steel parts (the company's staple product was sheet metal lanterns). Dr.-Ing. Werner Gruner, one of the leading design engineers with Großfuß, knew nothing about machine guns when he was given the task of being involved with the project, but he specialized in the technology of mass production. Gruner would attend an army machine gunner's course to familiarize himself with the utility and characteristics of such a weapon, also seeking input from soldiers. He then recycled an existing Mauser-developed operating system..."

"...He then recycled an existing Mauser-developed operating system..."

Was this Mauser-developed operating system a  roller locking?

There is a early (1933) Patent by Edward Stecke for a Automatic firearm that used a mechenism similar to a  roller locking system.



"...a weapon of devisement, contributed to by many, rather than the single invention of any individual...the locking was an adaption of the patented locking arrangement of Edward Stecke, a citizen of Warsaw, Poland. It is believed by many that, with the overrunning of Poland in 1939, one of the things seized by the Germans was a mock-up of a machine gun having Stecke's locking action. Realizing that it had many advantages, they added it to the list of fine features to be incorporated in a single ideal machine gun..."

"...designs captured when Poland was overrun appeared to promise a new and radical breech locking system...This was produced by the locking mechanism employed, a mechanism that was developed from several sources and was both simple and reliable. The system involved the use of two locking rollers running up and down an internal ramp: in the forward position they locked the breech very effectively by mechanical advantage and then allowed the ramp to release the locking..."

There aren't many Patents on the Roller Lock and Delayed system mechenisms used in the MG42 and/or the Mauser Short-Recoil Roller Lock or Roller Delayed Blowback used with the STG45,there is a MG42 type Roller Lock Patent that makes reference to a Patent by Paul Kurt Johannes Grossfuss from 1938 Verschluss fuer Rückstoßlader...

There is this Paul Mauser Patent,but it is not a Roller...





This Paul Mauser Patent for a mechenism for a Recoil-operated firearm.





But this Paul Mauser Patent (Recoil-loading rifle) may be the one used as a basis for the mechenism for the MG-42.

It uses a plate with two cam tracks and two side livers with cam one cam pin per lever,as the plate moves back/from its cam tracks force the cam pins to move out/in to open/close the levers,this action of having two side cams moving/caming inside cam tracks in order to open/close is very similar to the operation of the MG-42 bolt...



This Patent mechenism was used in the Mauser M1916 (Mauser Selbstlade-Karabiner).

"The Mauser M1916, or Mauser Selbstlade-Karabiner (Self-Loading Carbine), was a semi-automatic rifle that used a delayed blowback mechanism...The process of developing a semi-automatic rifle cost Paul Mauser an eye when a prototype suffered an out-of-battery detonation. The mechanism was quitete delicate, working reliably only when completely clean, which made the rifle unsuitable for infantry use."

side and top view of the Patent mechenism.





Top view.



with the cam plate front the cam pins in the side levers cam out to unlock,with the cam plate back the cam pins in the side levers cam in to lock.

There are multiple Patents for diferent sections of this mechenism.





Werner Gruner "...He then recycled an existing Mauser-developed operating system..."

There is always the chanse that Werner Gruner used the two Mauser Patent systems,combining the Patent mechenism that used a Shot-Recoil barrel and the one that used a fixed barrel with the cam plate and cam pin side levers in to a single Patent (to be found) Roller Lock mechenism?

Great post. Thanks!

Unlike the Roller Locked MG42,the MG45 (MG42V) used a Roller Delayed Blowback.

MG39 Roller Lock.



MG45 Roller Delayed Blowback.





"...it did not completely lock its breech before firing...had a different operation mechanism that used a delayed blowback as opposed to roller locking."

The Rheinmetall MG60 was a Prototype made by Rheinmetall,it was based in the MG45 (MG42V)

Firme Johannes Grossfuss Roller Lock Patent,it exists...just need to find it...



"The Paul Kurt Johannes Grossfuss Metall-und Lackierwarenfabrik in Doblen, Saxony had no previous experience in the manufacture of small arms, however, it was recognized as a leader in the development of techniques for manufacture by means of sheet metal stampings.

The Grossfuss prototype submitted on 26 October 1937 used a truly unique method of operation developed by Dr. Werner Gruner, their chief designer. The bolt system was recoil-operated and roller locked. Gruner had no previous experience with small arms and had no record of military service.

Gruner's demonstration model consisted of only two sidewalls and a bolt locking mechanism. The most significant feature of Gruner's design was the receiver, which was made from two sheet metal stampings. The world's first sheet-metal machine gun, the so-called MG39 was followed by the MG39/41. Series production of the MG42 commenced in 1942 by Maget, a Rheinmetall subsidiary..."

... Grossfuss prototype submitted on 26 October 1937...the patent for the Zweiteiliger Verschluss fuer Rueckstosslader was filed in 1938,it must be this patent but it comes with no description or drawings...

And there is this Patent from 1954 by Gerhard Freudig and Theodor Loffler from Rheinmetall Gmbh for a Bolt assembly for semi-automatic firearms that looks to be similat to the G3 Roller Bolt and receiver.

Theodor Löffler,a former Mauser engineer,working for the French CEAM (Centre d’Etudes et d’Armement de Mulhouse) came up with a prototype (designated as Model 50/1) used the same roller-delayed blowback system from the StG-45(M),in this Patent he is working for Rheinmetall Gmbh.
Ludwig Vorgrimler,also a former Mauser engineer and working for the French CEAM (Centre d’Etudes et d’Armement de Mulhouse) came up with a rototype functionally identical to the StG-45(M) but as hes prototype came second to the prefered prototype from Theodor Löffler,Ludwig Vorgrimler left  the French CEAM and went on to work to Spain at CETME (Centro de Estudios Technicales de Materials Especiales),his prototype for CETME was almost identical to the prototype made by Theodor Löffler at CEAM because "...Löffler's designs won out. Vorgrimler then devoted his efforts to improving Löffler's designs...".
Ludwig Vorgrimler returned to work at Mauser as the head of research and development.

Theodor Löffler CEAM (Centre d’Etudes et d’Armement de Mulhouse) prototype 50/1 (Carabine Mitrailleuse Modèle 1950)







Theodor Löffler and Ludwig Vorgrimler used the same Mauser Roller Delayed Blowback system.

Ludwig Vorgrimler

"Early career
Vorgrimler worked as an engineer for several arms manufacturers over his long career. He briefly worked for the Krupp factory from January to November, 1936. From there, he was recruited by Ott von Lossnitzer, the director of Mauser Werke's Weapons Research Institute and Weapons Development Group. Vorgrimler remained with Mauser until August 1945. He was ultimately assigned to Department 37, which was responsible for military small arms up to 15 mm in caliber. Vorgrimler eventually led the sub-department in charge of aircraft weapon construction. By January 1944, Vorgrimler was ordered to design a heavy machinegun using the roller-delayed blowback operating system then under development for military rifles. In response, Vorgrimler attempted to convert the gas-operated roller-locked MG215 to the roller-delayed system. Work was not completed by the end of the Second World War. Vorgrimler would later claim that he participated in the development of the MG45, a conversion of the roller-locked MG42 to roller-delayed operation."

German Assault Rifle, NATO 7.62mm, CETME, G-3



















Spanish 7.62mm Light Machine Gun Model "Mauser - CETME"

The Metall- und Lackwarenfabrik Johannes Großfuß company was also responsable for a diferent Delayed Blowback firearm,the Grossfuss Sturmgewehr (designed by Kurt Horn) was a Gas-delayed blowback (Gasdruckverschluss fuer selbsttaetige Feuerwaffen),it used a diferent operation from the Volkssturmgewehr 1-5 (designed by Karl Barnitzke)



"Kurt Horn found an innovative solution to this problem, the gas delayed blowback (German: Gasdruckverschluss). The idea was relatively simple: part of the gasses escaping from the chamber were redirected in the direction opposite to the rearward movement of the bolt; their pressure pushed against a piston connected to the bolt itself, thus decelerating the reward movement of the latter."



Karl Barnitzke,designer of the Volkssturmgewehr 1-5 (Gas Delayed Blowback) was also in charge of converting the MP43 in to a Blowback operation.

"At the Gustloffwerke, Suhl, Barnitzke, the chief designer, was given the specific problem of converting the existing MP43 design to blowback operation. No specific date had been assigned to the beginning of this project, but it may be assumed that the work started early in 1944, or possibly late 1943. Barnitzke states that an MP43/1 was selected for the experiment"

"...The blow-back modification to the M.P.43/1 mentioned under the paragraph on the Haenel Works, was an attempt to simplify the mechanism of the gun. It was realized that the more powerful cartridge of this weapon would present problems if the recoiling parts were not specially slowed down and this first attempt included a gas buffer. The barrel and gas cylinder shield, the gas block, and the piston and breech block assembly were removed from the standard weapon. The gas vent in the barrel was covered by a sleeve which blanked it off and the original gas block replaced on the barrel, without drilling a new vent, purely as a bearing for a new 'control' rod. The piston extension was fitted with a longer, and smaller diameter rod that the original piston rod, and had the standard breech block welded to it. This was welded on in the same relative position it would have in the normal gun in the closed and locked position. The locking shoulder was then ground off to enable the breech block to move backward and forward freely. At the muzzle end of the control rod a cylindrical gas chamber was fastened. This could slide back over the barrel of the gun and act as a pneumatic buffer when filled with the muzzle gases so as to ease the backward movement of the recoiling portions..."

LUDWIG VORGRIMLER Bolt Patent " Improvements in or relating to straight pull breech mechanisms for fire arms" they use straight pull as to Delayed Blowback as a description for the patent,this is not the patent but just a improvement done to it.

...on top of the Patent PDF,go to PAGE and click in the box to select Drawings and run the pages front/back...

List of other Patensts by LUDWIG VORGRIMLER

The probable reason for the non existing original Roller Delayed Blowback Patent from Mauser is probably that they made and rushed it in to production as the Gerät 06(H) StG 45(M) for military testing after the failure of the roller-locked short recoil Gerät 06?

WERNER GRUNER/KURT HORN Laufauswechselungseinrichtung fuer Maschinengewehre Patent

"Mauser records indicate the existence of a Maschinenkarabiner Gerät 08, the nature of the design being a so-called machine carbine chambering the rifle cartridge. Gustloff and Knorr Bremse have been identified with this undertaking, and the Mauser Gerät 08 could represent such a project on the part of that plant."

There is a Bullpup prototype made by KNORR-BREMSE that fits some of the general technical characteristics from this Mauser Maschinenkarabiner Gerät 08.

One problem with the KNORR-BREMSE is that no bolt or other internal parts exist,only the receiver strocture.

"GERMAN ASSAULT RIFLE KNORR-BREMSE 8MM
Manufactured by - Shop prototype Knorr-Bremse assault rifle. Very obscure. Needs more research. Wood grips. Many internal parts missing. No visible markings. Challenge: Kreighoff - trans. model - gas-operated, roller locking."

The  KNORR-BREMSE prototype fits the description of a  "...machine carbine chambering the rifle cartridge..." from the Mauser Maschinenkarabiner Gerät 08.

"...Challenge: Kreighoff - trans. model - gas-operated, roller locking.",did it use the same roller-locked short recoil mechanism used in the Gerät 03 and Gerät 06?

Can it be that this Mauser Maschinenkarabiner Gerät 08 and the KNORR-BREMSE prototype are one and the same?

Synopsis:Independently of the exact origins of the Roller System,what stands out is the intention of the German military thinking (at the time) was the need for the simplification of the bolt operation and structure in order to reduce cost (per unit) and to better adapt to the military field combat tactics and needs.The NATO generation in charge of acquiring equipment to combat the Soviet Union at the time of the Cold War is the same generation that fought the Soviet Union during WW2.Having this in mind it is reasonable to assume that the CETME/H&K G3 was a easy choice to be made as it embodies that same thinking,specialy when this as its developed constantly made by the same German engineers since its birth.

You win the technical forum    

That's awesome information. Thanks for sharing.

The MG45 uses a Roller Delayed Blowback developed in 1944 by Metall- und Lackwarenfabrik Johannes Großfuß.



The STG45(M) uses a Roller Delayed Blowback developed in 1944 by Mauser.



The two Roller Delayed Blowback mechenisms were developed by diferent manufactures in 1944 and have diferent mechanical operational geometries,is there a relation between the two?

"Nach den 1944 eingeführten Materialsparmaßnahmen wurde eine vereinfachte Version des MG 42 gefordert. Die Firma Mauser entwickelte daraufhin eine vereinfachte Variante des MG 42, während zeitgleich die Firma Großfuß das MG 42V oder MG 45 mit einem masseunterstützten Rollenverschluss konstruierte. Diese Waffe wurde bereits im Juni 1944 erprobt. Die weitere Entwicklung zog sich jedoch in die Länge, so dass bei Kriegsende nur zehn Waffen gefertigt waren."

"According to the 1944 austerity measures introduced material is a simplified version of the MG 42 was required. The Mauser company then developed a simplified version of the MG 42 while at the same time the company Puvel the MG MG 42V or 45 designed with a weight-assisted closure role. This weapon has been tested in June 1944. However, further development took in the length so that when the war ended only ten weapons were manufactured."

"...material shortages of the Third Reich led to the development of a newer version of the MG 42, the MG 45 (or MG 42V). This had a different operation mechanism that used delayed blowback as opposed to roller locking."

Großfuß had already developed the Roller Lock MG42 and then the simplified Roller Delayed Blowback MG 45/42V,but history credits Dr. Karl Maier ,from Mauser,as the Inventor/creator of the Roller Delayed Blowback out of the Roller Locked Gerät 03,and later on used in the Roller Delayed Blowback Gerät 06(H)/STG 45(M)

"What Maier realized was happening during these out-of-spec firings was that the rollers were resting on the angled sides of the wedge when discharged, instead of on the main parallel sides of the block. As a result, the force pushing back on the bolt would slide the rollers in by itself, without and input from the piston needed. This sequence of events kept rolling around in Maier’s head while he worked, and by the middle of January 1944 he had conceptualized a brand new action, which would be simple and cheaper still than the roller lock.

If Dr. Karl Maier came up with the idea for the Roller Delayed Blowback from the Gerät 03,why did Mauser started with the Roller Locked Gerät 06 and not just with the Roller Delaysed Blowback Gerät 06(M)?

neat