What Happens If You Accidentely Switch Ammo?

cirelaw · 06-25-2017, 12:47 AM

I was researching my 1902 fat Barrel and its written that the original mag was marked 9mm/cal to remind the owner that it took the larger 9mm. What would happen if a commercial 7.65mm round is loaded instead? Would it load or even shoot. I have a 1906 French contract which has an unmarked mag that would fit both calibre~ but has a 7.65mm barrel! Basically are they interchangable depending on the gun? Eric

Chickenthief · 06-25-2017, 05:03 AM

The only difference between a 9mm gun and a 7,65x21 is the barrel and recoil spring.

Since the Parabellum does not have controlled feed (as the 98K Mauser) where the round pass up under the extractor at loading, the 7,65 would plunk to deep into a 9mm chamber. Even if it was held in place by the extractor it would fire with a plop and straighten the case, nothing more.

9mm COL is 1.169"
7.65 COL is 1.175"
So the magazines would'nt know the difference either.

Dwight Gruber · 06-25-2017, 06:48 AM

In the Parabellum the round does, indeed, rise up under the extractor when stripping from the magazine.

--Dwight

mrerick · 06-25-2017, 10:00 AM

The 9mm Parabellum round headspaces on the mouth of the straight walled cartridge.

The 7.65mm Luger round is a bottle neck cartridge that headspaces on the shoulder of the cartridge.

I don't recommend testing this, but would there be enough chamber support to ensure that the extractor would engage the cartridge rim, and enough support for the firing pin to actually strike into the primer?

kurusu · 06-25-2017, 10:20 AM

Either it will go bang if it gets held by the extractor. And it wiil be poultry snatcher's scenario. Or, it will go all the way in untill the bottleneck shoulder hits the end of the chamber and nothing will happen cause the striker won't reach the primer.

The 9mm marking on the magazine bottom serves another purpose. It will avoid to inadvertly put a 9 mm loaded magazine in a .30 Luger chambered pistol. Those rounds will not chamber, and you will be either embaressed or defensless depending on the situation.

We used both as service pistols. First in different branches (Army and Navy), and after 1942 in all services except the Air Force.

cirelaw · 06-25-2017, 08:13 PM

I refound a 9mm/Cal injured old mag I bought years ago for $20 long before I bought my 1902 Fat Barrel. It appears legit~Looks like it got run over!!!! Eric

ithacaartist · 06-28-2017, 02:12 PM

Eric,

I think G.T. might be able to improve/re-do the repair. Otherwise, we remember his exact copies of the walnut 9mm marked mag bottoms!

cirelaw · 07-08-2017, 11:24 PM

Tks I'll give him a shout!

06-25-2017, 12:47 AM	#1
cirelaw Lifer Lifetime Forum Patron Join Date: Dec 2003 Location: PORT ST LUCIE, FLORIDA Posts: 12,216 Thanks: 6,209 Thanked 4,133 Times in 2,173 Posts	What Happens If You Accidentely Switch Ammo? I was researching my 1902 fat Barrel and its written that the original mag was marked 9mm/cal to remind the owner that it took the larger 9mm. What would happen if a commercial 7.65mm round is loaded instead? Would it load or even shoot. I have a 1906 French contract which has an unmarked mag that would fit both calibre~ but has a 7.65mm barrel! Basically are they interchangable depending on the gun? Eric Attached Thumbnails

06-25-2017, 10:00 AM	#4
mrerick Super Moderator - Patron LugerForum Life Patron Join Date: Dec 2009 Location: Eastern North Carolina, USA Posts: 3,909 Thanks: 1,374 Thanked 3,110 Times in 1,510 Posts	The 9mm Parabellum round headspaces on the mouth of the straight walled cartridge. The 7.65mm Luger round is a bottle neck cartridge that headspaces on the shoulder of the cartridge. I don't recommend testing this, but would there be enough chamber support to ensure that the extractor would engage the cartridge rim, and enough support for the firing pin to actually strike into the primer? __________________ Igitur si vis pacem, para bellum - - Therefore if you want peace, prepare for war.

06-25-2017, 08:13 PM	#6
cirelaw Lifer Lifetime Forum Patron Join Date: Dec 2003 Location: PORT ST LUCIE, FLORIDA Posts: 12,216 Thanks: 6,209 Thanked 4,133 Times in 2,173 Posts	I refound a 9mm/Cal injured old mag I bought years ago for $20 long before I bought my 1902 Fat Barrel. It appears legit~Looks like it got run over!!!! Eric Attached Thumbnails

06-28-2017, 02:12 PM	#7
ithacaartist Twice a Lifer Lifetime Forum Patron Join Date: Mar 2011 Location: Atop the highest hill in Schuyler County NY Posts: 3,347 Thanks: 7,285 Thanked 2,579 Times in 1,366 Posts	Eric, I think G.T. might be able to improve/re-do the repair. Otherwise, we remember his exact copies of the walnut 9mm marked mag bottoms! __________________ "... Liberty is the seed and soil, the air and light, the dew and rain of progress, love and joy."-- Robert Greene Ingersoll 1894

06-25-2017, 05:03 AM	#2
Chickenthief User Join Date: Dec 2016 Location: Denmark Posts: 135 Thanks: 0 Thanked 131 Times in 48 Posts	The only difference between a 9mm gun and a 7,65x21 is the barrel and recoil spring. Since the Parabellum does not have controlled feed (as the 98K Mauser) where the round pass up under the extractor at loading, the 7,65 would plunk to deep into a 9mm chamber. Even if it was held in place by the extractor it would fire with a plop and straighten the case, nothing more. 9mm COL is 1.169" 7.65 COL is 1.175" So the magazines would'nt know the difference either.

06-25-2017, 06:48 AM	#3
Dwight Gruber User Join Date: Jun 2002 Location: Portland, Oregon Posts: 3,902 Thanks: 0 Thanked 1,318 Times in 431 Posts	In the Parabellum the round does, indeed, rise up under the extractor when stripping from the magazine. --Dwight

06-25-2017, 10:20 AM	#5
kurusu User Join Date: Sep 2007 Posts: 1,225 Thanks: 2,679 Thanked 930 Times in 509 Posts	Either it will go bang if it gets held by the extractor. And it wiil be poultry snatcher's scenario. Or, it will go all the way in untill the bottleneck shoulder hits the end of the chamber and nothing will happen cause the striker won't reach the primer. The 9mm marking on the magazine bottom serves another purpose. It will avoid to inadvertly put a 9 mm loaded magazine in a .30 Luger chambered pistol. Those rounds will not chamber, and you will be either embaressed or defensless depending on the situation. We used both as service pistols. First in different branches (Army and Navy), and after 1942 in all services except the Air Force.

07-08-2017, 11:24 PM	#8
cirelaw Lifer Lifetime Forum Patron Join Date: Dec 2003 Location: PORT ST LUCIE, FLORIDA Posts: 12,216 Thanks: 6,209 Thanked 4,133 Times in 2,173 Posts	Tks I'll give him a shout!