Boring vs Sleeving

unspellable · 07-10-2002, 09:17 AM

Simple experiment: I dropped a 7.63 Mauser case into a 9 mm P08 (Don't do this with a loaded round boys and girls!) and it will not chamber or come close to chambering. As previously mentioned, this indicates the 7.63 Mauser chamber is bigger in some places than the 9 mm chamber so boring one out to 9 mm will not be entirely satisfactory. There will be oversized areas. This change really should be done by sleeving.

On the other hand, a 7.65 mm Parabellum case will chamber in a 9 mm P08 so boring a 7.65 barrel out to 9 mm may be practical.

But here's the offshoot observation. We have long assumed the 9 mm Parabellum was a developemnt of the 7.65 mm Parabellum. Looking at sketches of the early DWM experiments for a 9 mm cartridge and considering the above I am starting to think the 9 mm was developed directly from the 7.65 Borchardt or 7.63 Mauser case and did not derive from the 7.65 Parabellum case as has been generally ssumed.

07-10-2002, 09:17 AM	#1
unspellable User Join Date: Jun 2002 Location: Iowa Posts: 768 Thanks: 0 Thanked 19 Times in 11 Posts	Boring vs Sleeving Simple experiment: I dropped a 7.63 Mauser case into a 9 mm P08 (Don't do this with a loaded round boys and girls!) and it will not chamber or come close to chambering. As previously mentioned, this indicates the 7.63 Mauser chamber is bigger in some places than the 9 mm chamber so boring one out to 9 mm will not be entirely satisfactory. There will be oversized areas. This change really should be done by sleeving. On the other hand, a 7.65 mm Parabellum case will chamber in a 9 mm P08 so boring a 7.65 barrel out to 9 mm may be practical. But here's the offshoot observation. We have long assumed the 9 mm Parabellum was a developemnt of the 7.65 mm Parabellum. Looking at sketches of the early DWM experiments for a 9 mm cartridge and considering the above I am starting to think the 9 mm was developed directly from the 7.65 Borchardt or 7.63 Mauser case and did not derive from the 7.65 Parabellum case as has been generally ssumed.