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

Where would the 7.62X25 Russian fit in? I don't have the technical info but they would be hot enough. What is the case length on the .30 Luger?


Roadkill

[unspellable]

The 7.62 Tokarev doesn't fit in, literally, it's too long. The original cartridge behind all this was the 7.65 Borchardt. Mauser used a hotter loading for the 7.63 Mauser. Herr Luger shortened it to make the 7.65 Parabellum. Shortening was required to make room for the recoil spring in the grip. The Soviets made some minor diminsional changes in the 7.63 Mauser to come up with the 7.62 Topkarev, but it has the same overall length as the Mauser and is too long to go through the Luger magazine well. There are a couple of other obscure cartidges based on the 7.65 Borchardt.


If you roll your own, it's easy to heat up the 7.65 Parabellum, just dump in more powder. Exactly how much is something I have yet to determine. I do know there is a lot of room to spare as far as pressure goes. Just upping it to the same pressure levels as the current 9mm loadings should do the job. There is a mytery in the question of how we came to have such wimpy factory loads.


unspellable

[Lonnie Zimmerman]

This same problem was around with the early loads for the 9mm.


Lonnie

You might want to try a faster burning power such as Bullseye. Tom h.

[The Wizard]

Unspellable,

Have you treid any of the Finish (Lapua 1981) surplus 7,65 mm Parabellum sold by Samco Global Arms. It seem to work find in my Mauser-Parabellum 06-73 with 150 mm barrel. I have only shoot about 100 rounds of the stuff and I do not have any way to measure velocities. Will have to do some shooting for accuracy but being bind in one eye and not being able to see out of the other may have some effect on that data. Will disassemble one tonite to measure bullet and powder.

The Wizard

[Hugh]

With the 90 & 93 gr Hornady .308 bullets, 5.5 gr Unique, 6.5 gr HS7, 7.5 gr Bluedot, & 5.6 gr SR4756 works in my guns with either 4" or 6" bbls.