Study Identifying Luger Caliber: .30 Luger or 9mm Luger?

mrerick · 05-13-2012, 08:02 PM

Here are some illustrations to help with identifying the caliber your luger was made in.

The original Luger cartridge was the .30 Luger (7.65x21mm Parabellum), a bottleneck cartridge. The chamber that this cartridge fits into has a stepped shape that supports the bottleneck.

The 9mm Luger (9mm x 19mm Parabellum) cartridge has a similar cartridge base, and does not have the bottleneck. This is why the one Luger magazine design can work with both cartridges.

Several posts mention the "pencil test". The fact is that a hex shaped (sharp edges) No. 2 pencil Will snugly fit down a .30 Luger caliber barrel. A round No. 2 pencil generally will not fit down the .30 Luger barrel.

Both pencils will loosely fit down a 9mm Luger barrel.

The pictures attached to this post are annotated.

They first show a 9mm cartridge placed in a .30 Luger barrel's chamber. It will NOT fit properly into this chamber, and would do damage if it went off (photos are of a dummy cartridge). It will stick out of the chamber, and the toggle train will not go into battery.

Next, pictures show how a 9mm Luger round will rest on the end of a .30 Luger barrel, and a 9mm Luger barrel.

Next, a Hex No. 2 pencil fits tightly into a .30 Luger barrel, and a Round No. 2 pencil rests on top of the .30 Luger Barrel.

Next, a Hex No. 2 pencil fits loosely into a 9mm Luger barrel, and a Round No. 2 pencil fits loosely into a 9mm Barrel.

Hope that these help you identify the caliber of your Luger!

Marc

alanint · 05-13-2012, 08:38 PM

Hard to believe, but this "primer" seems to have been necessary lately...
Thanks, Marc!!

sheepherder · 05-13-2012, 09:08 PM

Here's my contribution - 7.65mm Luger on left; 9mm Luger on right...

And since most of us will have a 5/16" drill bit lying around, the bit will fit in a 9mm barrel but not a 7.65mm barrel...

(It'll be a very sloppy fit in the 9mm)

lugerholsterrepair · 05-13-2012, 09:15 PM

Rich..And since most of us will have a 5/16" drill bit lying around, the bit will fit in a 9mm barrel but not a 7.65mm barrel...

That's not true! I turned on my drill and it went right in! Few shavings and chips but in it went!

HAHA! Seriously... should move this over to a sticky. Good Job Rich and Eric

rhuff · 05-14-2012, 06:32 PM

Excellent illustrations in an easy format.

Douglas Jr. · 05-15-2012, 11:13 AM

A very nice tutorial, that proved needed lately.

Don M · 05-15-2012, 01:52 PM

Quote:

Originally Posted by lugerholsterrepair

That's not true! I turned on my drill and it went right in! Few shavings and chips but in it went!

We need to keep Jerry away from power tools!

Best stick with a needle and thread, Jerry!

mrerick · 01-31-2013, 11:03 AM

This question keeps coming up. Sticky?

Marc

John Sabato · 01-31-2013, 02:09 PM

Excellent Tutorial on distinguishing .30 caliber from 9mm. I will make it a "sticky"!

cirelaw · 04-23-2017, 04:44 PM

Up until 1908 with the exception of the commercial fat barrel 1902, 7.65 including the Swiss was the only calibre that I am aware! All the 1908 models Army, Commercial and Military were the 9mm. A few 1920 carbines retained the smaller calibre 7.65. as many used leftover parts during the Weimer era~

lugerholsterrepair · 04-23-2017, 04:53 PM

Was there a specific time when the switch occurred from 7.65 x 21mm (.30 Luger) bottleneck cartridge to the 9 x 19mm Parabellum cartridge? Yes, almost immediately after George Luger invented it.

Was this transition across the board (did all manufacturers change simultaneously)? Yes, since there was only one manufacturer, DWM.

What was the reason for the change (i suspect it had to do with the forever argued concept of knockdown power)? Exactly! Good guess! There is little to argue about here really. BIGGER is better 100% of the time.

flydive · 04-23-2017, 05:11 PM

Quote:

Originally Posted by lugerholsterrepair

Was there a specific time when the switch occurred from 7.65 x 21mm (.30 Luger) bottleneck cartridge to the 9 x 19mm Parabellum cartridge? Yes, almost immediately after George Luger invented it.

Was this transition across the board (did all manufacturers change simultaneously)? Yes, since there was only one manufacturer, DWM.

The 7.65(.30 Luger) was in production till 1947, so there were no switch as such, but parallel production.

05-13-2012, 08:02 PM	#1
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	Study Identifying Luger Caliber: .30 Luger or 9mm Luger? Here are some illustrations to help with identifying the caliber your luger was made in. The original Luger cartridge was the .30 Luger (7.65x21mm Parabellum), a bottleneck cartridge. The chamber that this cartridge fits into has a stepped shape that supports the bottleneck. The 9mm Luger (9mm x 19mm Parabellum) cartridge has a similar cartridge base, and does not have the bottleneck. This is why the one Luger magazine design can work with both cartridges. Several posts mention the "pencil test". The fact is that a hex shaped (sharp edges) No. 2 pencil Will snugly fit down a .30 Luger caliber barrel. A round No. 2 pencil generally will not fit down the .30 Luger barrel. Both pencils will loosely fit down a 9mm Luger barrel. The pictures attached to this post are annotated. They first show a 9mm cartridge placed in a .30 Luger barrel's chamber. It will NOT fit properly into this chamber, and would do damage if it went off (photos are of a dummy cartridge). It will stick out of the chamber, and the toggle train will not go into battery. Next, pictures show how a 9mm Luger round will rest on the end of a .30 Luger barrel, and a 9mm Luger barrel. Next, a Hex No. 2 pencil fits tightly into a .30 Luger barrel, and a Round No. 2 pencil rests on top of the .30 Luger Barrel. Next, a Hex No. 2 pencil fits loosely into a 9mm Luger barrel, and a Round No. 2 pencil fits loosely into a 9mm Barrel. Hope that these help you identify the caliber of your Luger! Marc Attached Thumbnails __________________ Igitur si vis pacem, para bellum - - Therefore if you want peace, prepare for war. Last edited by mrerick; 04-23-2017 at 07:55 PM.

05-13-2012, 09:08 PM	#3
sheepherder Lifer Lifetime Forum Patron Join Date: Feb 2009 Location: ...on the 'ol Erie Canal... Posts: 8,182 Thanks: 1,400 Thanked 4,442 Times in 2,330 Posts	Here's my contribution - 7.65mm Luger on left; 9mm Luger on right... And since most of us will have a 5/16" drill bit lying around, the bit *will* fit in a 9mm barrel but *not* a 7.65mm barrel... (It'll be a very sloppy fit in the 9mm) Attached Thumbnails __________________ I like my coffee the way I like my women... ...Cold and bitter...

05-13-2012, 09:15 PM	#4
lugerholsterrepair Moderator Lifetime Forum Patron Join Date: Jun 2002 Location: Arizona/Colorado Posts: 7,771 Thanks: 4,928 Thanked 3,124 Times in 1,434 Posts	Rich..And since most of us will have a 5/16" drill bit lying around, the bit *will* fit in a 9mm barrel but *not* a 7.65mm barrel... That's not true! I turned on my drill and it went right in! Few shavings and chips but in it went! HAHA! Seriously... should move this over to a sticky. Good Job Rich and Eric __________________ Jerry Burney 11491 S. Guadalupe Drive Yuma AZ 85367-6182 lugerholsterrepair@earthlink.net 928 342-7583 (CO & AZ) Year Round 719 207-3331 (cell) "For those who Fight For It, Life has a flavor the protected will never know."

01-31-2013, 11:03 AM	#8
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	This question keeps coming up. Sticky? Marc __________________ Igitur si vis pacem, para bellum - - Therefore if you want peace, prepare for war.

01-31-2013, 02:09 PM	#9
John Sabato Lifer Lifetime Forum Patron Join Date: Jun 2002 Location: The Capital of the Free World Posts: 10,154 Thanks: 3,003 Thanked 2,306 Times in 1,097 Posts	Excellent Tutorial on distinguishing .30 caliber from 9mm. I will make it a "sticky"! __________________ regards, -John S "...We hold these truths to be self-evident that ALL men are created EQUAL *and are endowed by their Creator* with certain UNALIENABLE* rights, and among these are life, LIBERTY, and the pursuit of happiness..."*

05-13-2012, 08:38 PM	#2
alanint User Join Date: Mar 2008 Location: Marco Island, Florida Posts: 4,867 Thanks: 1,685 Thanked 1,916 Times in 1,192 Posts	Hard to believe, but this "primer" seems to have been necessary lately... Thanks, Marc!!

05-14-2012, 06:32 PM	#5
rhuff Patron LugerForum Patron Join Date: Mar 2011 Location: Az. Posts: 2,291 Thanks: 2,708 Thanked 972 Times in 717 Posts	Excellent illustrations in an easy format.

05-15-2012, 11:13 AM	#6
Douglas Jr. User Join Date: Aug 2002 Location: South America Posts: 948 Thanks: 598 Thanked 584 Times in 254 Posts	A very nice tutorial, that proved needed lately.

04-23-2017, 04:44 PM	#10
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	Up until 1908 with the exception of the commercial fat barrel 1902, 7.65 including the Swiss was the only calibre that I am aware! All the 1908 models Army, Commercial and Military were the 9mm. A few 1920 carbines retained the smaller calibre 7.65. as many used leftover parts during the Weimer era~ Attached Thumbnails

04-23-2017, 04:53 PM	#11
lugerholsterrepair Moderator Lifetime Forum Patron Join Date: Jun 2002 Location: Arizona/Colorado Posts: 7,771 Thanks: 4,928 Thanked 3,124 Times in 1,434 Posts	Was there a specific time when the switch occurred from 7.65 x 21mm (.30 Luger) bottleneck cartridge to the 9 x 19mm Parabellum cartridge? Yes, almost immediately after George Luger invented it. Was this transition across the board (did all manufacturers change simultaneously)? Yes, since there was only one manufacturer, DWM. What was the reason for the change (i suspect it had to do with the forever argued concept of knockdown power)? Exactly! Good guess! There is little to argue about here really. BIGGER is better 100% of the time. __________________ Jerry Burney 11491 S. Guadalupe Drive Yuma AZ 85367-6182 lugerholsterrepair@earthlink.net 928 342-7583 (CO & AZ) Year Round 719 207-3331 (cell) "For those who Fight For It, Life has a flavor the protected will never know."