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German cross Filling and Adjusting the PT34  German cross

Excercise photo from period publication

(Picture by courtesy of Carles in Barcelona)
The picture above shows a MG34 with a PT34 in a staged manouver photo. Note how the top-strap is interfering with the line-of-sight, as it hasn't been depressed properly after the installation of the magazine.

Filling the Patronentrommel 34

To be able to fill the PT34 the user will need some kind of tool. The answer was a special machine named Trommelfûller 34. It consisted of a gearbox, a vice, a hand crank and a funnel. All parts could be stowed inside a standard Patronkasten 34.

 Trommelfüller 34

Designations for the Trommelfüller 34  
The different parts are shown above with the correct names. A empty magazine was inserted upside-down on the rail below the funnel. 
The Trommelfüller 34 is described in D124/1 as late as in 1941, so obviously it must have seen some use between 1934 and 1941.
Instructions are quite simple: Insert a empty magazine, make sure the followers are visible in the "0" window at the rear of the magazine. If this is not the case, use the Trommelschlüsseln to adjust.


Trommelschlüsseln und Sperrohr zu den Trommelschlüsseln

Fill the funnel with 75 rounds. As the magazine will not function properly if it is overfilled, it is important that the correct number of cartridges is put into the funnel. By turning the crank-handle the drum will be filled with the cartridges placed in the funnel.

To empty the magazine, place it upside down and use a stick of hardwood and press the cartridges forward one at the time until the magazine is empty. Of note is the fact that the D-T 15 had a specially designed tool made of bakelite for this purpose!

Up untill now, no surviving example has been known to exist. Then this set of pictures surfaced in France!

Trommelfuller 34        Trommelfuller 34
Pictures courtesy of Gurtsack France!

This clearly is a surviving example of the Trommelfüller 34.

And then another Trommelfüller 34 was "unearthened" in Russia!

This picture by courtesy of David in Moscow! This one has clearly been dug up, but is very interesting as it is displayed in parts!

And again, the D-T 15 was issued with a loader of it's own that apparently also could be used with the PT34. It consisted of a simple wood-board that held the magazine upside-down, a ratchet mechanism with a lever-arm and a very small "funnel"/stripper-clips holder.

DT-15 loader with PT34

DT-15 loader with PT34

Loader for the Doppeltrommel 15

Adjusting the Patronentrommel

The PT34 was a finely tuned machinery. Too weak springs would lead to feed-failure, and too hard springs would lead to the gun jamming, as the bolt spring would be unable to overcome the pressure of the cartridges against the magazine lips. To top this, both springs would need to work perfectly in synchronization to ensure that the feeding occurred from both drums. The drum spring-adjustment was not carried out by the user. The manual clearly states that any trouble with the feeding should first be remedied with the Trommelschlüsseln. "Wiederholen sich Störungen bei einzelnen Patronentrommeln, so ist die Federspannung durch das Waffentechnische Personal zu verändern". If feeding problems persist with specific PT34's, the springs should be adjusted by Ordnance personnel! It is easy enough to figure out how it was done, but not the correct procedure applied. None of the handbooks I have access to says anything about the actual process.


PT34 cover disk

To get access to the springs, the two disks covering the holes on the front plate must be removed. The two tiny screws are permanently affixed to the disks, so they will not be lost! With the disks removed the construction of the simplified spring is easy to see!


PT34 spring teeth

The coiled spring has a final that goes across the last coil. This straight piece of the spring is arrested in teeth that follow the inner wall of the front plate all around the hole, so that two opposing teeth will always hold the coil in the right place and tension. When the covering disk is installed it will lock the coil final  in the choosen position.

Kleines waffenmeister Kiste

The coil can be adjusted with a pair of pliers, but the Germans had of course designed a special tool for the job! The name of it is not known. My example came with a “Kleines Waffenmeister Kiste” and was manufactured in 1943, the same year as the PT34 definitively had gone out of fashion! This one was made by “dpq”, Bruno Mädler, Werkzeugfabrik, Berlin. 

PT34 tool

The tool is very simple to use. First make sure the locking lever is not covering the axis between the notches in the tool, insert it into the hole and make sure the notches and the coil final lines up. Then turn the locking lever so that the coil final is held firmly arrested in the notches of the tool. The coil can now be wound and unwound with the tool while pressing the spring in so that the final disengages from the teeth. Pulling the tool out will bring the coil final into locking position between the teeth again!

PT34 tool released

When the adjustment has been made, the locking arm is turned again and the tool can be withdrawn.

PT34 markings

(Pictured above is a PT34 that was sold on the WAF in 2008)

The front of the magazine housing has impressed a “0”, presumably for zero tension, an arrow indicating increased pressure (these arrows point in opposite directions of course) and a “V”, presumably for Verschärfung (tightening). Also note that the springs have been painted red or white (picture further up), and that the colour of the markings on the magazine housing corresponds with the springs. Most probably to ensure that the correct spring was installed on the correct side!

My best guess in regards to adjustment is that the spring was “zeroed”, and then it was ensured that the cartridges were held firmly in place. Too weak springs would allow cartridge # 2 to jam in the feeding. Springs would have to be tightened until feeding ran smoothly. Over tightening the springs would lead to feed failure, as the pressure of the bolt spring would be unable to overcome the magazine spring pressure on the cartridges. This procedure would be done on the gun with “Werkzeugpatronen” (tool-cartridges) or by using a broken firing pin, and repeatedly cycling the gun by hand with the magazine installed.

Final approval would acquire the gun to be test-fired with a full magazine.

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