Thread: 6.5 v 7mm

I see youre using a 284.

Maybe you could get a used 6.5-284 barrel brass and dyes from an F Class shooter and make an exact comparison with all the same gear but different bore size.

Only use 10mm and up, because more is better!

Originally Posted by Micky Duck

and the only TRUE 7mm the .277 to also consider....

@Micky Duck can you expand on this?

Wondering what you were talking about as I had always taken the box figures for granted e.g. 7mm/.284 I took a look at my wall conversion chart. And what do you know, 7mm is 0.2756". SO measuring a 7mm/.284 ELDX with the verniers comes in at 7.17mm/.2820 and a .270 NBT is exactly 7mm/0.2755. So now that my mind is blown, what is up with the naming? or measuring system seeing as they don't actually convert? Also, by the chart 5.56 is not 0.223" yet 7.62 matches 0.300".

I'm not sure but could be to do with barrel diameters, either inner or outer rifling measurement.

Curiosity got the better of me and I had to know.

https://en.m.wikipedia.org/wiki/Caliber

So it's not bullet diameter like all the reloading manuals list but approximations and there abouts of the barrel diameter. Except for the exceptions. Well I think I have learned something

But it still doesn't explain why a approximate 7mm projectile is also named 7mm at .284 and not 7.2mm. probably confusing myself now.

Yeah I have learnt a bit too. If you google it there's a lot of info.

Originally Posted by Micky Duck

shit loads of difference....you can shoot animal with your 7mm projectiles but you cant buy any 6.5mm ones to use.

Way more 6.5mm around

Same over here, 7mm are hard to source should you need them. 6.5 not so much except for the 143 eldx.


Sent from my iPhone using Tapatalk

Greetings All,
The calibre controversy has been going on for a long time. Up until WW2 smokeless rifle cartridges were mostly named for the bore dia (land to land measurement) hence .270 or 27 calibre, 7mm or 276 calibre. Post war some US cartridges started being named for groove dia .243 for 6mm or 236 calibre and .308 for 30 calibre. All this has got hopefully confused and the table in Wikipedia mentioned above is worse than useless in adding any clarity. With pistol and small rifle cartridges that were developed in the black powder era the situation is even worse and I wont even go there.
So sorry Micky your beloved .270 falls about 0.02mm shy of being a true 7mm calibre. It probably owes its existence to the US reluctance to use anything metric (softening lately) and Winchester picking the next calibre down from 7mm as .280 was already in use.
Regards Grandpamac.

Greetings All,
The calibre controversy has been going on for a long time. Up until WW2 smokeless rifle cartridges were mostly named for the bore dia (land to land measurement) hence .270 or 27 calibre, 7mm or 276 calibre. Post war some US cartridges started being named for groove dia .243 for 6mm or 236 calibre and .308 for 30 calibre. All this has got hopefully confused and the table in Wikipedia mentioned above is worse than useless in adding any clarity. With pistol and small rifle cartridges that were developed in the black powder era the situation is even worse and I wont even go there.
So sorry Micky your beloved .270 falls about 0.02mm shy of being a true 7mm calibre. It probably owes its existence to the US reluctance to use anything metric (softening lately) and Winchester picking the next calibre down from 7mm as .280 was already in use.
Regards Grandpamac.

Originally Posted by grandpamac

Greetings All,
The calibre controversy has been going on for a long time. Up until WW2 smokeless rifle cartridges were mostly named for the bore dia (land to land measurement) hence .270 or 27 calibre, 7mm or 276 calibre. Post war some US cartridges started being named for groove dia .243 for 6mm or 236 calibre and .308 for 30 calibre. All this has got hopefully confused and the table in Wikipedia mentioned above is worse than useless in adding any clarity. With pistol and small rifle cartridges that were developed in the black powder era the situation is even worse and I wont even go there.
So sorry Micky your beloved .270 falls about 0.02mm shy of being a true 7mm calibre. It probably owes its existence to the US reluctance to use anything metric (softening lately) and Winchester picking the next calibre down from 7mm as .280 was already in use.
Regards Grandpamac.

piss off Noddykins...take a .270w projectile and your micrometer/fancypants measuring stick....and then tell me its not 7mm.... the projectiles fired from a .270 winchester are closer to 7mm than any other projectile so the rest are fake poser wannabees.

! Mod theres something wrong here.

Originally Posted by Bagheera

! Mod theres something wrong here.

I had trouble posting, hence the two copies

@Micky Duck. Yes the .270 is an awesome cartridge. Just not as awesome as the .280 Rem. That's 'cause the .280 is a a 7mm and the .270 isn't. Hoew do you do an emoji of some one pissing themselves?