Gunblast article

[Spook]

Originally Posted by rsilvers

300 AAC BLACKOUT, with Remington factory 125 grain Match ammo, is 16.7% MORE energy than Lapua 7.62x39mm ammo - when measured at 300 meters. I picked Lapua for the comparison because it is the only ammo with accurate BC and velocity data - and also happens to chronograph as the hottest AK ammo I have found.

Wow! how much more energy does Rem 125 grain have over Lapua @ 100YDs?

[Titleiiredneck]

http://www.youtube.com/watch?v=Oa0RR...eature=related

[rsilvers]

Yes, I made videos of my 7.62x39mm AR working also.

[rsilvers]

Originally Posted by Spook

Wow! how much more energy does Rem 125 grain have over Lapua @ 100YDs?

There would be less of a difference at 100 yards. The 300 meter advantage was because of the more efficient BC of the 300 BLK bullet. Basically the 300 BLK starts out as less, and ends up as more and there is some range where they are equal.

[Spook]

http://youtu.be/PUgGKptKwvI

so did this guy as a matter of fact it seems lots of people have their 7.62 X 39's working nicely , unless they employed trick photography, or mirrors perhaps?

[Spook]

Originally Posted by rsilvers

There would be less of a difference at 100 yards. The 300 meter advantage was because of the more efficient BC of the 300 BLK bullet. Basically the 300 BLK starts out as less, and ends up as more and there is some range where they are equal.

...so would the energy advantage switch over to the X 39 @ 100 and @ 278 yds or so yds they'ed equal out?

Where's Lou Boyd?

[Titleiiredneck]

Originally Posted by rsilvers

Yes, I made videos of my 7.62x39mm AR working also.

Mine ran fine, cproduct mags and all. Used wolf and some old norinco and never broke a bolt either, even after 1200 rounds. The only problem I had was figuring out the gas port size since mine was only 8". Once I Figured that out it was gtg.

[LouBoyd]

Originally Posted by Spook

...so would the energy advantage switch over to the X 39 @ 100 and @ 278 yds or so yds they'ed equal out?

Where's Lou Boyd?

I'm not sure why your asking me. Calculating that is just a matter of running the two bullets in most any exterior ballistics program with their muzzle velocities, appropriate BCs, and weight as inputs, then checking energy vs distance to see where they cross.
The gun, cartridge, or even the caliber doesn't matter (within the limitations of the G() tables)

[rsilvers]

The reality is, 7.62x39mm - at least in surplus or steel cased form, is cheaper. So a lot of people are going to put up with it because it is buyable for 17 cents a round as Yugo surplus.

And then others, and also LE and Military, will never shoot surplus AK ammo. So when you compare the price of 300 BLK to newly-made brass cased 7.62x39mm - 300 BLK is actually about 40% cheaper.

[Spook]

Originally Posted by rsilvers

The reality is, 7.62x39mm - at least in surplus or steel cased form, is cheaper. So a lot of people are going to put up with it because it is buyable for 17 cents a round as Yugo surplus.

And then others, and also LE and Military, will never shoot surplus AK ammo. So when you compare the price of 300 BLK to newly-made brass cased 7.62x39mm - 300 BLK is actually about 40% cheaper.

Lovely. What does this have to do with energy levels?