Conversion 7.65 mm to 9 mm

tugbrass1 · 10-07-2012, 11:14 AM

I have an opportunity to purchase a 7.65 mm Luger that was made for the commercial market in 1920. I prefer the 9 mm ammunition. I have been doing research the about converting a 7.65 Luger to shoot the 9 mm cartridge. I have read many opinions on this subject. Some advise against it because they say the several other parts including the receiver need to be changed as well as the barrel. Others report that only the barrel and possibly the main spring need changing. I realize that a gunsmith would be required to do the work because of the head spacing concern. I would appreciate an informed opinion from an experienced Luger gun smith about the needed parts and a ball park cost figure.

Edward Tinker · 10-07-2012, 11:46 AM

I have moved this to the new collector area and also put you to be notified if someone responds.

Unless the 30 luger (7.65mm) is very cheap, you will spend more than if you just look around for a 9mm luger

alanint · 10-07-2012, 11:57 AM

All that really needs to be changed is the barrel, (properly headspaced) and the mainspring. verything else, including the magazine will work. I personally would not ruin an original 20's commercial pistol just to shoot 9mm. Buy a mismatched shooter grade 9mm for that and keep the commercial historically significant and unchanged.

sheepherder · 10-07-2012, 01:00 PM

Quote:

Originally Posted by tugbrass1

I realize that a gunsmith would be required to do the work because of the head spacing concern...

You would only *need* a gunsmith if the headspace/timing needed adjustment (re-cutting the chamber or turning down the barrel flange)...[IMHO]...You can check the headspace (after installing the new barrel) yourself...You would need a setup to remove & replace the barrel yourself, of course...

Even then, from my observations, it's not always necessary to 'adjust' anything...Again, IMO, the Luger barrel thread was milled rather than turned...Which meant the barrel could be timed and chambered off the receiver and come within design specs without any adjustment necessary...Especially with the generous tolerances/clearances of military (and wartime) production...

It's aftermarket barrels that require tweaking...

...IMHO...

rhuff · 10-07-2012, 05:37 PM

Another option you have, is the one that I chose. I own a 1921 DWM P08 in 30 Luger. Over a period of time I located a rebarreled 1939 receiver/barrel extension in 9mm. For a while, I used my original toggle train with both uppers, but recently purchased a complete Erfurt toggle train in excellent condition. I had to headspace the new 5in. bbl. but now I am able to switch back and forth between 30 Luger and 9mm. I have installed a mainspring that works for both calibers, and the same mags work also.

I am a reloader, so firing either caliber is not a big difference price wise. I just enjoy being able to shoot either caliber. My choice.

By having a complete upper, one does not have to risk a barrel change, and possible damage to the components. Just one more option for you to consider.

tugbrass1 · 10-07-2012, 06:51 PM

Thanks guys,
You answered all of my concerns. I have decided to purchase the 7.65 mm luger and keep it as a collector piece because the very sharp photo images indicate it is in a near pristine condition. I will also continue to look for a 9 mm "shooter" that can pass an inspection by a gun smith well versed in the P 08 Lugers. Over the decades I have acquired hand guns, rifles and shotguns that are fine representatives of both the military and civilian firearms. This is my first foray into the world of the Lugers. I don't think that there is another type of handgun that points as well as the elegant Luger. Never the less, I would rather bet my life on the 1911A1 when push come to shove. Actually, for close range self defense nothing beats a the Winchester Model 12. Did you notice the model numbers? P 08, 1911A1, Model 1912; I guess I'm just an old fashioned kind of guy!

Douglas Jr. · 10-08-2012, 10:24 AM

Quote:

Originally Posted by tugbrass1

Did you notice the model numbers? P 08, 1911A1, Model 1912; I guess I'm just an old fashioned kind of guy!

This only counts on your favor!
Welcome to the forum and congratulations for a wise decision.

10-07-2012, 11:14 AM	#1
tugbrass1 User Join Date: Oct 2012 Posts: 11 Thanks: 2 Thanked 0 Times in 0 Posts	Conversion 7.65 mm to 9 mm I have an opportunity to purchase a 7.65 mm Luger that was made for the commercial market in 1920. I prefer the 9 mm ammunition. I have been doing research the about converting a 7.65 Luger to shoot the 9 mm cartridge. I have read many opinions on this subject. Some advise against it because they say the several other parts including the receiver need to be changed as well as the barrel. Others report that only the barrel and possibly the main spring need changing. I realize that a gunsmith would be required to do the work because of the head spacing concern. I would appreciate an informed opinion from an experienced Luger gun smith about the needed parts and a ball park cost figure.

10-07-2012, 11:46 AM	#2
Edward Tinker Super Moderator Eternal Lifer LugerForum Patron Join Date: Jun 2002 Location: North of Spokane, WA Posts: 15,926 Thanks: 2,014 Thanked 4,523 Times in 2,089 Posts	I have moved this to the new collector area and also put you to be notified if someone responds. Unless the 30 luger (7.65mm) is very cheap, you will spend more than if you just look around for a 9mm luger __________________ Edward Tinker ************ Co-Author of Police Lugers - Co-Author of Simson Lugers Author of Veteran Bring Backs Vol I, Vol II, Vol III and Vol IV

10-07-2012, 11:57 AM	#3
alanint User Join Date: Mar 2008 Location: Marco Island, Florida Posts: 4,867 Thanks: 1,685 Thanked 1,916 Times in 1,192 Posts	All that really needs to be changed is the barrel, (properly headspaced) and the mainspring. verything else, including the magazine will work. I personally would not ruin an original 20's commercial pistol just to shoot 9mm. Buy a mismatched shooter grade 9mm for that and keep the commercial historically significant and unchanged.

10-07-2012, 05:37 PM	#5
rhuff Patron LugerForum Patron Join Date: Mar 2011 Location: Az. Posts: 2,288 Thanks: 2,702 Thanked 971 Times in 716 Posts	Another option you have, is the one that I chose. I own a 1921 DWM P08 in 30 Luger. Over a period of time I located a rebarreled 1939 receiver/barrel extension in 9mm. For a while, I used my original toggle train with both uppers, but recently purchased a complete Erfurt toggle train in excellent condition. I had to headspace the new 5in. bbl. but now I am able to switch back and forth between 30 Luger and 9mm. I have installed a mainspring that works for both calibers, and the same mags work also. I am a reloader, so firing either caliber is not a big difference price wise. I just enjoy being able to shoot either caliber. My choice. By having a complete upper, one does not have to risk a barrel change, and possible damage to the components. Just one more option for you to consider.

10-07-2012, 06:51 PM	#6
tugbrass1 User Join Date: Oct 2012 Posts: 11 Thanks: 2 Thanked 0 Times in 0 Posts	Thanks guys, You answered all of my concerns. I have decided to purchase the 7.65 mm luger and keep it as a collector piece because the very sharp photo images indicate it is in a near pristine condition. I will also continue to look for a 9 mm "shooter" that can pass an inspection by a gun smith well versed in the P 08 Lugers. Over the decades I have acquired hand guns, rifles and shotguns that are fine representatives of both the military and civilian firearms. This is my first foray into the world of the Lugers. I don't think that there is another type of handgun that points as well as the elegant Luger. Never the less, I would rather bet my life on the 1911A1 when push come to shove. Actually, for close range self defense nothing beats a the Winchester Model 12. Did you notice the model numbers? P 08, 1911A1, Model 1912; I guess I'm just an old fashioned kind of guy!