5.45x39 Conversion Question


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OneShot!
June 16, 2007, 06:35 AM
Can anyone tell me how to convert the Ak 74 caliber to such as 5.56X45 is converted in .223? And what will be that conversion?
Thanks.

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KadicDeshi
June 16, 2007, 10:02 AM
If you mean converting to imperial from metric, then 5.45 ~ .215.

Hope this helps.

Barrett

Nightcrawler
June 16, 2007, 10:08 AM
A US company produced in AR-15 upper in 5.45mm for some reason. They dubbed the round ".21 Genghis".

OneShot!
June 16, 2007, 10:26 AM
Is it possible that the convertion comes out to be .222?
What is the formula and methods for this procedure?
Thank you.

MudPuppy
June 16, 2007, 10:54 AM
I'm a bit confused on what you're asking, but if you're just asking how metric is converted to inches (caliber), that's one thing.

But if you're expecting that to be an accurate indicator of true dimensions, firearms are often listed as different than what they truly are.

If you're asking how to convert a 5.45 AK into a 5.56, the "right way" would be a new bolt (bullet case diameter is bigger on a 5.56, iirc) and a new barrel, then head space it. (I'm pretty sure a 5.56 bolt interchanges on the carrier of the same make/nationality AKs).

Sorry for being a bit slow today, its early yet. :o

KadicDeshi
June 16, 2007, 11:33 AM
Is it possible that the convertion comes out to be .222?
What is the formula and methods for this procedure?

Nope. Or at least not if the 5.45 dimension given is the actual diameter of the bullet.

5.45mm/(25.4mm/in)=0.2145669in or thereabouts.

Max Velocity
June 16, 2007, 11:42 AM
5.56 millimeters = 0.218897638 inches, but that is the BORE diameter which is the diameter measured at top of the lands. Bullet diameter for 5.56x45mm is actually .224" or 5.6896 millimeters which is barrel groove diameter.
5.45 millimeters = 0.214566929 inches, but the nominal bullet diameter for 5.45x39mm is 5.62mm (.221")

1 millimeter = 0.0393700787 inches
1 inch = 25.4 millimeters

OneShot!
June 16, 2007, 02:51 PM
Thank you. This is really technical. I thank you for helping me. I think as I understand the measurement comes out to be .221?

Fyooz
August 7, 2007, 11:38 PM
I miked the bullet on a 5.45mm 7N6 cartridge, and it is .221 diameter.

Have no idea where to get reloading components for this cartridge, but then the 7N6 ammo that's available by the spam can goes for about $.15 per round delivered.

Would like to roll some dummy rounds for dryfiring, though.

Father Knows Best
August 8, 2007, 12:18 AM
I think as I understand the measurement comes out to be .221?
Um, what "measurement" are you referring to? The diameter of the bullet? If so, then yes, a projectile from a 5.45x39 cartridge measures approximately 0.221 inches in diameter.

There is no "conversion" involved, however. You mentioned in the your first post the 5.56x45 and .223. 5.56x45 NATO is one cartridge, and .223 Remington is another. They are very similar, and the 5.56x45 NATO was developed by the military from the civilian .223 Remington cartridge. One uses metric (millimeters) specifications, and one uses English (inches). They are not the same cartridge, though they are close enough that some firearms can use them interchangeably.

The Russian 5.45x39 was developed as a military cartridge. As far as I know, there is no civilian cartridge that is dimensionally similar to it.

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