7.62 vs 5.45

Noob question:
How does the Ak 47 7.62 round compare to the AK 74 5.45 in terms of accuracy, range, and power?
I get the more rounds/less weight argument, but does it work for a SHTF weapon?
thanks

The trajectory of the 5.45 will be more flat. Obviously the 7.62 will be more powerful. Accuracy, I've heard 5.45 is more accurate. SHTF, I have a '74.

Check this thread as well.

http://www.akfiles.com/forums/showthread.php?t=3187&highlight=trajectory

I love the 5.45x39 love it...

but be advised you want bullet placement, penetration, and wound channel.
both 7.62x39 and 5.45x39 are awesome

most firefights will be anywear from zero- to 50 yards away depending on the conditions of where you are.

if the bad guy is close and shooting at you....
i want the biggest knock down power

Beware of some Tantal barrels as they won't stabilize a bullet very well at all.

In the 1930's and 1940's the Soviets tested 22 caliber, 6.5mm and 7.62mm bullets and at that time determined that 7.62mm worked best. Finland and Yugoslavia have come to the same conclusion. It's been found that the wounding effect of a non-fragmenting 22 caliber rifle bullet, even at rifle velocities, doesn't wound any more than handgun bullets. Of course it does have greater range than handgun ammo.

Now 5.45mm ammo does have it's own special powder and case capacity to maximize the cartridge. It's fairly accurate. The Russian do use tapered cases and straighter wall cases are usually more accurate but I doubt you'd see a difference in an AK.

The Russian bullets are only full diameter at a narrow point behind the case mouth. Russian rifle cambers have a tapered throat (leade) from the case mouth to the rifling that tapers to about the land diameter not the groove diameter like other countries. This squeezes the bullet a bit as it enters the rifling. Finland uses a more conventional designed chamber similar to Mauser and US designs in 7.62x39.

In Theory a fast moving .22 can deliver the same energy as a .30. In reality this has proven to be untrue except in perfect or specific situations.

7.62 x 39 for penetration.

Penetration is not a dirty word, it is very desirable in some situations.

The 7.62x39 FMJ has the same wound ballistics as the .30-30. It yaws once, then exits, as do most rifle bullets.

The 5.45x39 FMJ 7N6 will yaw multiple times and typically does more damage than the 7.62.

There have been several articles on this including studies by Dr. Marvin Fackler. Just about any search will turn up something. Bottom line, 5.45 is good for wound ballistics, but the 7.62 is better for heavy cover.

The 7.62x39 FMJ has the same wound ballistics as the .30-30. It yaws once, then exits, as do most rifle bullets.

The 5.45x39 FMJ 7N6 will yaw multiple times and typically does more damage than the 7.62.

There have been several articles on this including studies by Dr. Marvin Fackler. Just about any search will turn up something. Bottom line, 5.45 is good for wound ballistics, but the 7.62 is better for heavy cover.

It's been found since then that yawing in 22 caliber rifle bullets, that don't fragment, doesn't add much to the wounding effect and only compares to handgun bullets in wound effect. The 30 caliber bullets have been found to do much better, even at lower velocities. The 22 caliber bullets have to fragment to be equal. The yawing is given much less credit these days.

the original 7.62x39 was judged in 520mm barreled SKS's and RPD's with early AK-47's thought more of special sub machine guns. When the Soviets switched to the AK as the standard rifle finding velocities dropping in extreme cold they worked to redesigned the 7.62x39 a bit. Originally they judged it in the KS and against the 7.92x33mm. Originally it had to penetrate a steel helmet at 1000 meters and better 7.92x33mm. around 1960 they made it a bit more accurate but the bullet shape had a bit more drag. They also worked to improve the wounding in the newer version. Finland did a lot of caliber testing too.