Need explanation on where 6.5 came from?

Plank Road Farm · 12-20-2007, 05:35 PM

Just bought a M96 recently and have been doing a lot of reading about the 6.5 x 55mm caliber.

I understand that the cartridge is 55mm (2.165 in.) long.

I am not understanding where the 6.5 come from?

Since, 6.5 mm x 0.03937 inches/mm = 0.2559 or 0.256 in.

How did this caliber get its name when it uses a 0.264 in. diameter bullet?

The 0.264 in. / 0.03937 inches/mm = 6.7 mm

There must be some kind of caliber designation liberty involved here or something?

Can anyone shed some light on this issue?

If I have posted this question on the wrong forum, please move or erase it.

K75RT · 12-20-2007, 06:05 PM

.264 is the groove diameter of the barrel and the .256 is the bore diameter.

Plank Road Farm · 12-20-2007, 08:08 PM

I knew there had to be a simple answer.

I won't ask that question again.

Thanks, K75RT!

nathangdad · 12-20-2007, 09:46 PM

This caliber in the Mauser action really "burst forth" from the regions of Sweden and Finland. Later they used it in a machinegun.

rfc357 · 12-20-2007, 09:48 PM

Not all 6.5s shoot a .264 bullet. Look at the specs for the Carcano.

Plank Road Farm · 12-20-2007, 10:17 PM

Quote:

Originally Posted by rfc357

Not all 6.5s shoot a .264 bullet. Look at the specs for the Carcano.

How is that, does the rifling change and the bore stay the same?

samuel · 12-20-2007, 10:34 PM

The 6.5mm came to America and was renamed the .264". sam.

SwedeSteve · 12-21-2007, 07:36 AM

The Swedes were way ahead of the times on this one. Def a superb round!

rfc357 · 12-21-2007, 08:03 AM

Welcome to the confusing world of cartridge nomenclature. Get a copy of "Cartridges of the World" and spend a quiet evening with an adult beverage, a roaring fire, and this fascinating book.

What would you guess is the bullet diameter of the 330 Dakota? Hint: It's not .330.

12-20-2007, 05:35 PM	#1
Plank Road Farm Member Join Date: Dec 2006 Location: Cameron, NC Posts: 21	Need explanation on where 6.5 came from? Just bought a M96 recently and have been doing a lot of reading about the 6.5 x 55mm caliber. I understand that the cartridge is 55mm (2.165 in.) long. I am not understanding where the 6.5 come from? Since, 6.5 mm x 0.03937 inches/mm = 0.2559 or 0.256 in. How did this caliber get its name when it uses a 0.264 in. diameter bullet? The 0.264 in. / 0.03937 inches/mm = 6.7 mm There must be some kind of caliber designation liberty involved here or something? Can anyone shed some light on this issue? If I have posted this question on the wrong forum, please move or erase it.

12-20-2007, 08:08 PM	#3
Plank Road Farm Member Join Date: Dec 2006 Location: Cameron, NC Posts: 21	Groove and Bore diameters I knew there had to be a simple answer. I won't ask that question again. Thanks, K75RT!

12-20-2007, 09:46 PM	#4
nathangdad Senior Member Join Date: Nov 2007 Posts: 3,226	6.5 historical military heritage This caliber in the Mauser action really "burst forth" from the regions of Sweden and Finland. Later they used it in a machinegun.

12-21-2007, 07:36 AM	#8
SwedeSteve Thor's Hammer Join Date: Feb 2007 Location: Alaska Posts: 14,121 Images: 1	The Swedes were way ahead of the times on this one. Def a superb round! __________________ Thank God we don't get as much Government as we pay for! -Will Rogers

12-20-2007, 06:05 PM	#2
K75RT Senior Member Join Date: Mar 2002 Location: Litchfield County, Connecticut Posts: 449	.264 is the groove diameter of the barrel and the .256 is the bore diameter.

12-20-2007, 09:48 PM	#5
rfc357 Senior Member Join Date: Jun 2006 Posts: 741	Not all 6.5s shoot a .264 bullet. Look at the specs for the Carcano.

12-20-2007, 10:34 PM	#7
samuel Senior Member Join Date: Dec 2006 Posts: 6,081	The 6.5mm came to America and was renamed the .264". sam.

12-21-2007, 08:03 AM	#9
rfc357 Senior Member Join Date: Jun 2006 Posts: 741	Welcome to the confusing world of cartridge nomenclature. Get a copy of "Cartridges of the World" and spend a quiet evening with an adult beverage, a roaring fire, and this fascinating book. What would you guess is the bullet diameter of the 330 Dakota? Hint: It's not .330.