Carcano,
I understand perfectly what is being said here. .257 equates to 6.5mm. I just don't agree with some of the statements that have been made here. They are confusing and misleading to someone who might be just starting out in reloading and I don't think we are doing those people any favors here with this discussion.
I'm glad that we can agree on one thing though and that is the fact that good beer should not be wasted. As for the crow pie.....I don't eat it unless I'm wrong!! Jim

Carcano91,
I think the point Jim was making was to save someone from taking their head off. A new reloader could easily get confused and have a serious problem. I think some of the sarcasm could be put on the shelf in the interest of safety.
Stepchild

Well, ya'll had me second guessing what my buddies .257 Roberts really was. I see lots of 6.5mm dia bullets, and they all say .264" on them too, not once did I see a .257" say 6.5mm. I'd think someone could have in all their efforts here, as Jim did, spelled it out for the guys reading that wouldn't know.

Seems that reloading manuals do not recognize the 257 Roberts as a 6.5mm in the sense most understand it... that it shoots the commonly recognized 6.5mm/.264" bullet, to me that's the important thing here, and you all had plenty of opportunity to admit.

You're right tho, we all have a responsibility to know what our guns shoot, regaurdless of what might be typed or spoken to make a point, claimed or whatever. I certainly take responsibility for my actions, and blame no one for my lack of brains when I make the ultimate decision and pull the trigger. I ain't here to babysit, but I try and do my best not to mislead. Ultimately, it's in your court...

Damnit, I thought my buddies was a 6.5 after all, why the hell they don't make a 140 SMK for the 257 is beyond me, but it sure could use one.

[ 09-25-2003, 12:10: Message edited by: Brent Moffitt ]

There's a whole world of confusion and danger awaiting those who misunderstood my post.
To be clear, The following combinations must not be attempted:
260 Remington with .260" bullets.
340 Weatherby with .340" bullets.
380 Special with .38" bullets.
404 Jeffery with .404" bullets.
6.53 Scramjet with 6.53mm bu - oh, wait, that works.
7mm Remington Magnums, with 7mm bullets.
577 T-Rex with .577" bullets.
577-416 Martini Henry with EITHER 577" or .450" bullets.
Bullets for your 9.3x63 Brenneke with those for your 9.3x72 Rimmed.

I'm tired of typing, so the rest of you will just have to slug your barrel!

To be ultra clear, the bullets that go in "6.5mm" guns are .264", which is NOT equal to 6.5mm.
The reason they say "6.5mm" on the box is NOT because the bullets measure 6.5mm, but because the gun they are to be shot in has a 6.5mm HOLE in the barrel.

{I say this all in good fun! Forgive me for not worrying about "new, impressionable reloaders." like I said, if they screw this up, there's no telling what else they're going to to do.)

Ok, they say 6.5mm or 6.5mm caliber one or the other along side the .264 dia on the box, as I'm sure you knew that was my point. The .257 dia do not say 6.5mm on them, the .264's do.

True, they do not say 6.5mm "dia" next to the .264" dia. I'll eat my pie now.

Hmmmm, not that this may interest anybody, but since I posted yesterday I went home and had a look at my reference material. It actually transpires, that there was a period (maybe from end of the 19th into about the middle of the 20th century) where no less than 2 caliber groups were actually designated "6.5mm" in Europe. This was a bit surprising to me, but at least it provides an explation for why the Europeans seem to have a tendency to talk of 6.5mm for both .257" and .264" calibers.

I found at least the following "6.5mm" caliber designations with .257" bullets: 6.5x52R (apparently equivalent to a US caliber 25-35), 6.5x58R and 6.5x70R.

Amazingly, during the same period, at least the following .264" caliber cartridges were also designated 6.5mm: 6.5 Carcano, 6.5x54 Mannlicher Schoenauer, 6.5x55, 6.5x57.

Cartridge history never ceases to amaze me
- mike

And just for shits and giggles, the 256 Newton, which uses 264 bullets. - Dan

Fun with math time, 25.4 mm in an inch gets you:

25.4 x .257 = 6.5278 or 6.5mm for .257" or 6.35mm cartridges

25.4 x .264 = 6.7056 or 6.7mm for .264" or 6.5mm cartridges

25.4 x .510 = 12.954 or 12.9mm for .510" or 12.7mm cartridges

So in fact any cartridge that shoots a .257 inch DIAMETER bullet is shooting 6.5mm DIAMETER bullets. You have to remeber that with metric cartridges, the name almost always refers to the BORE diameter, not the GROVE diameter. Grove dimentions usely run about 0.2mm large then bore. So the .257's, which are 6.3's in meteric designation shoot 6.5mm diameter bullets.

The big exception to that is Lazzeroni wich is why the .30 caliber cartridges in his line is are 7.82 Warbird and 7.82 Patriot.
25.4 x .308 = 7.8232

Kristofer

[ 09-27-2003, 02:18: Message edited by: KBGuns ]