SMG ammo at over 1400 fps. The need for a powerful magazine spring is the reason that the WWI Luger magazines with their wooden bottoms were later replaced with extruded magazines with aluminum bottoms that could accomodate stronger springs for greater reliability. Overall cartridge length is important also. The steep angle of the magazine is only 1.070 inches front to back, which dictates a maximum overall cartridge length of 1.180 inches with very little under that acceptable.
While the Luger likes a slow push recoil, the Browning-design pistols of today like a hot primer and a sharp recoil. Consequently most of today’s ammo is made for their functioning needs, which are the exact opposite of the Luger’s. Also, their overall length does not always lie within the Luger’s operating lengths. Like the M16, the Luger is sensitve about the ammo used in it.
To keep the lock from cycling too fast, the WWI German Army Luger load was a 115-grain bullet at 1,025 fps. A slow-burning, single-base nitrocellulose powder with a high silica content that slowed ignition coupled with slightly underpowered low-flame primers gave a slower burning curve and a slower push, resulting in a slower cyclic time to allow proper feeding and reliability. WWII ammo was also slower burning but with a 124-grain bullet and, later, a 130-grain bullet. Mauser Werke altered the spring strength of the German Army’s Lugers for this ammunition. Ammunition marked for machinepistol use (MP-38, MP-40) was loaded with extra-hot primers that make the Luger cycle too fast for reliability. The best American powder for Lugers is Red Dot shotgun powder as it most closely equals the WWI powder’s burning and acceleration rate. 4.1 grains of Red Dot and a 115-grain bullet will give 997 FPS and 3.9 grains of Red Dot and a 124-grain bullet will give 1,025 FPS. Winchester primers are the best American primers for Lugers because they are the least likely to be pierced by the Luger’s long firing pin. When that happens, gas can go back through the firing pin hole, pushing the firing pin and spring back and ripping the back out of the breechblock. The extractor may also be forced up and torn out of the breechblock.
Like all Lugers, the Krieghoff has an immediately-identifiable profile.
Prior to WWII, Germany put three relief grooves in the firing pin to let the pressure from a pierced primer go past the firing pin instead of driving it as a piston backwards. The Finns drilled a hole in the bottom of the breechblock into the firing pin area to bleed gas off in their guns.
A grouping of unfinished Krieghoff Luger parts from the bench of master gunsmith Frank Kaltenpoth.
The 9mm Parabellum cartridge has always presented problems for gun designers because its tapered case can give uneven pressures in an automatic. The tapered case grips the chamber and if there is dirt in the vicinity, the tapered case wedges in it and jams instead of pushing it forward into the chamber as a straight case does. As a result, no 9mm Parabellum can function reliably with a rough or dirty chamber. The 9mm Parabellum also has a high chamber pressure of 36,000 psi, which can rise into the low 40,000 psi range if a bullet is bumped and set back into the case. This is not the sort of pressure the light Borchardt toggle liked and, remember, it was not beefed up in mass when it became the Luger.
The tapered 9mm cases also gave feeding problems in the Luger’s sharply-inclined magazine where they tend to tilt and create extra drag in addition to the side drag, resulting in a magazine that has difficulty feeding cartridges to the super-fast toggle action before the bolt rides into the top side of the cartridge instead of the cartridge base because the cartridge hasn’t had time to rise up to full feeding position. The problem was compounded by the Luger’s incredibly light weight of 30 ounces, which lets the muzzle flip up more in recoil as the cartridges in the magazine are simultaneously driven down by that flip – this on a magazine whose angle of feed dictates that it be so precisely positioned that a worn magazine catch or a magazine that hangs too low will cause feeding jams.
Georg Luger had originally designed his gun for the .30 Luger cartridge, which was well balanced to the design. Someone took the case and opened it up to 9mm for a bolt action “garden gun” cartridge, in which role its tapered case was an aid to extraction. About this time, the German police experienced several failures of the 93-grain .30 Luger to stop a determined assailant, so DWM ordered Georg Luger to chamber the Luger for the new 9mm cartridge as this would only require rebarreling. Georg pointed out the aforementioned objections plus the fact that the heavier bullet would have a larger recoil impulse than the lightweight toggle had sufficient mass to resist. Bottom line: business cost-cutting overruled the designer and Georg’s protests fell on deaf ears.
To his credit, Georg Luger made the gun work with a less than perfect cartridge for it. When you consider the initial strikes against it and the final outcome, you realize that this is one of the finest triumphs of German firearms engineering.
The Luger was inspired by the Maxim Machinegun and indeed Hiram Maxim referred to it as a Maxim machinegun in pistol form. (He also considered it a patent infringement.) Like the Maxim, the Luger is an incredibly long-lived gun. According to Alfred Gallifent, a Swiss Federal Certified Armorer who was qualified to work on the Swiss Army’s Lugers, the five most common Luger repairs in order of frequency were 1) the grip screws were buggered up by someone with an ill-fitting screwdriver; 2) the L-shaped spring that retains the takedown lever would break; 3) the leaf spring on the M1900 would break; 4) the receiver forks would break when some idiot dropped it on concrete; and 5) the transfer bar from the trigger to the sear was buggered up by people tinkering with it and bending it in an attempt to get a better trigger pull.
Precision machining at its finest.
The Krieghoff Luger in its high-tech case, itself something of a work of art.
When these are the most common repairs on guns in continuous service since 1900, you have a most excellent design.
THE NEW KRIEGHOFF
An enormous amount of research went into ensuring that the new Krieghoff Lugers were absolutely perfect continuations of the WWII production run. Krieghoff’s production drawings did not all survive the war intact but the Bavarian Main State Archives, Department 4, War Archives in Munich had the “Dimension Tables” for the P08. Original Krieghoff P-code pistols were carefully studied to ensure exact duplication of the technical details unique to the Krieghoff Luger. Precise duplicates of the original marking stamps such as the Krieghoff “sword/anchor logo” were made. Molds were made to produce duplicates of the original military brown bakelite grips and tooling produced to once more make the WWII Krieghoff PO8 magazine and aluminum magazine bottom. Original gun barrels were copied to make the correct land and groove pattern on the new barrels. This is unheard-of attention to technical detail in a recreation.
The Krieghoff Luger, disassembled.
Great attention was given to getting the precise bluing colors of the original, a job complicated by new environmental laws banning some of the original ingredients in the blueing formulas. However, Krieghoff succeeded with true Teutonic precision. Every color is absolutely the same. The full attention of this German industrial giant was devoted to getting every detail exactly right. The finish has no tool marks except for the obligatory milling machine swirls in the safety area which also had to be exactly reproduced. A Luger without these would just not be an authentic Luger.
The parts all begin as precision forgings
