7.65 mm Parabellum cartridge

[unspellable]

Well I finally made it out to the range with the chronograph and the news is not good.


I used two Lugers, a DWM Model 1920 mismatch with the usual 98 mm barrel, very crispy, and a 1942 Mauser military with a 5 inch 7.65 tube on it, also crispy. Five inches is an unusual length but I rather like the appearance, it just looks right, not too long, not too short.


First I had some hand loads made up with 4.6 grains of Unique and the Plinker bullet. In the 98 mm DWM these averaged 979 fps, not really in the ball park. Although the extra weight in the bullet helped the functioning it still wasnâ??t hot enough to be reliable. This is easily remedied by dumping in a little more powder.


Now the bad news: In the DWM, Winchester factory loads averaged 1048.3 fps with an extreme spread of 133.6 fps in ten rounds. Not at all up to the 1220 Winchester claims from a 4.5 test barrel. This load might be OK in an old model with a somewhat tired leaf spring but it just isnâ??t hot enough for an up to snuff Luger.


In the Mauser this load averaged 1184.3 fps with an extreme spread of 86.5 fps. Notice that an inch of barrel has bought us 136 fps. This is consistent with the pronounced muzzle flash, says the powder is on the slow side. Itâ??s a flake powder by the way.


Fiochi from a silver box averaged 1140.0 fps in the Mauser with an extreme spread of 97.8 fps.


Fiochi from a maroon box averaged 1067.3 fps in the Mauser with an ES of 105.7 fps. At this point the Mauser went on strike and refused to reload. About eight out of the ten shots I had to rack the empty out and a new one in, effectively converting a self loader into a repeater.


The velocities for all three factory loads are simply too low to expect reliable operation. If you want it done right you have to roll your own. The variability is quite large too. This combined with the muzzle flash and the gain in velocity from adding an inch of barrel argues the powder is on the slow side and a light charge that is not working up enough pressure to burn consistently.


Throw in the sloppy bullets and itâ??s amazing that we get the accuracy we do. Winchester claims 0.309 plus 0.000, minus 0.003 for bullet diameter. I pulled one and it measured 0.3090 inch. I pulled a Fiochi and it measured 0.3080 inch. Iâ??m convinced that with good ammo the average Luger would be a tack driver.


I really think DWM was serious when they said 1220 fps for a 93 grain bullet from a 98 mm barrel.


The bottom line is that the factory ammo is made for some firearm other than a 7.65 Luger. I will be in conatct with Winchester again and also plan to contact Fiochi and SAAMI. Iâ??m going to get to the bottom of this. By the way, SAAMI says 28,400 psi for the 7.65 and 32,400 psi for the 9. What gives? Same action! The pistol gets weaker when you have thicker barrel walls? If anything the 7.65 needs to run more pressure than the 9 to get enough impulse to operate the action.


Iâ??ve only had two or three people forwarding measurements from their 7.65 barrels. Come on people, pass me some info. I really mean to solve the question of what to feed a 7.65 mm Luger based on facts and not old hand me down bad information. Iâ??m really convinced the big boys have this one all wrong.


Unspellable