explain

>>32535257
You're an idiot. Explanation enough?

>>32535265
not enough

>>32535257
alot of calibers are named after the diameter of the barrel. since the bullet needs to be bigger then the barrel to grab the rifling bullets are often larger then the caliber they are named after. 45acp and 9mm bullets are slightly larger then .45 inches or 9mm. not sure where or when that started.

as for case length not sure but thank god they rounded it off. 7.62×39mm is long enough, no need for 7.62x38.70mm

>>32535257
OK. The format for metric measurement of small arm ammunition goes like this
1.7.62x2.39mm.
>1.The 7.62mm is the diameter of the bullet. Not the caseing, just the bullet.
>2.39mm this is the length of the case, not the over all length just the case.
Better?

the actual size of a milimeter has changed due to inflation

>>32535401
AUDIT THE FED

from here on out we shall refer to 7.62x39 as 8x39

File: 135905491449.jpg (106KB, 1572x583px) Image search: [Google]

106KB, 1572x583px

>>32535370
I was thinking maybe it was rounded, but rounding 7,92 into 7,62 doesn't make a sense. If it's really rounded for case, why there is no consistency with bullet?

I also thought maybe 7,62 is exactly 1/3 of inch but it also isn't it.

Also are you sure about barrell?

File: 1280px-7.62_x_54_R_cartridge.svg.png (62KB, 1280x800px) Image search: [Google]

62KB, 1280x800px

>>32535385
No, not better.

>>32535257
The bullet is bugger that the core diameter of the barrel, this allows the bullet to swaige under force into the rifling, this is what causes the rifling to grip and force the bullet to spin

0.3mm is an easy running tolerence of magazines

>>32535257
Russian's cant measure, they fucked up the diameter and are too ashamed to admit to it.

>>32535575

It's the barrel diameter.

Depends on the place of origin if its measured between the lands(high points) or the grooves(low points).

>>32535737
>barrel
>bore

>>32535575
just measured my AKM and the diameter of the bore at the muzzel w/o a break is .3 inches. that converts to 7.62mm. i think you're looking at the outer dimensions which dont matter for the question you're asking

File: qweqweqwe.jpg (1007KB, 2902x999px) Image search: [Google]

1007KB, 2902x999px

>>32535370
>>32535687
>>32535737
Actually I just found decent lecture about bullet measurement and labeling and you are right. 7,62 is diameter of barrell so it's about gun that is needed to fire bullet which is marked with this number.

>Depends on the place of origin if its measured between the lands(high points) or the grooves(low points).
Why isn't this standarized?

Also I assume it's diameter of this part of the barrell?

File: image.jpg (98KB, 858x536px) Image search: [Google]

98KB, 858x536px

>>32535385
Holy fuck, could you be more wrong?

>>32535783
>Why isn't this standarized?
casue countries like making their own standards, especially when they're trying to kill other countries who impose standards.

glad you learned something today. post the lecture plz

>>32535826
I doubt there's point in posting since chances you know that one of eastern european languages that isn't russian are rather low.
But here, have it if you want.
http://mczbron.blog.pl/jak-oznaczane-sa-naboje/
http://rzutek.phpzilla.net/Lufa.htm?i=1

Also what are differences between shotgun and rifle barrells besides rifling?

>>32535903
google translate

size and thickness. shotgun barrels tend to be larger (a 12 ga is like what, 3/4's of an inch) and tend to be thinner. rifle barrels tend to be smaller in bore diameter but thicker compared to diameter. fun fact gauge is measured by how many times you can spit a pound of lead into equal spheres.

>>32535958
Google translator is shit for texts and good as single word dictionary.

And these are all the differences?

>>32536020
biggest ones you'll notice. material, manufacturing, life, way they connect will all be different. hell, they make rifled shotgun barrels. but someone else will chime in.

>>32536087
Thanks. Then last question: why case length is rounded while barrel diameter isn't?

>>32536128
already said i dont know >>32535370

this guy is prolly right tho >>32535687
it probably does not matter that much so round up

>>32535401
>>32535404
Kek

File: 1478043835625.jpg (199KB, 867x989px) Image search: [Google]

199KB, 867x989px

>>32535257
I've heard one explanation before, but I cannot confirm for certain:
Soviets measured their bores from land to land, while Westerners measure from groove to groove.