5.45 vs. 5.56: Russian Improvement of the idea?

[VirgilCaine]

How is the 5.45 different from the 5.56?

See, I had this thought that the Russians, having made the transition to a small-caliber high-velocity round ten years after the West, would have looked at the performance of the 5.56 and improved it.

Is this true?

I read on another, older thread on here that the 5.45 has a larger area where is performs relatively optimally vis a vis terminal ballistics compared to the 5.56. Something about bullet weight and tumbling. Sounded like what I'm thinking of, but is there anything else?

 

[HorseSoldier]

I think the 5.45 round has more case taper, which would assist with cycling under less than optimal conditions.

As for terminal ballistic performance, the Russians may have missed the boat, at least from what I've read. They developed their 5.45x39 round at a time when people in the US believed that 5.56x45 ammo relied upon rapid tumbling effect to produce debilitating wounds. So the Russians developed a round that tumbled even better than 5.56mm, which was an improvement . . . except that it later turned out that 5.56x45 punched above its weight via fragmentation, rather than tumbling.

That said, mil-spec 5.45x39 is not unlike M855 green tip, with a steel core, and in close (CQB sort of) range shooting tests of armor materials I'd say it is a somewhat superior penetrator, or at least as good as green tip. (Hard to say which, as I'm pretty sure any and all of my college stats professors would smack me if I tried to pretend I've seen a big enough sample to be statistically significant.)

 

[Browning]

The only thing that I really know about the 5.45X39 comes from reading gun magazines and from articles as I've never owned one. That said, if I remember right though the 5.45 actually measures out to be a little bigger than a .22 (.224 I believe). It's achieving basically the same velocity in a shorter case with the same grain bullet and it's cheaper to produce than most 5.56 ammo as most of the 5.45 out there is steel cased. Like HS said above I also think that the 5.45 case also has more of a taper for better reliability.

Then there's the fact that when coming up with the round the Soviets wanted a high velocity round that made a very large wound channel when it exited like how the 5.56 was found to do in Vietnam. When the 5.56 was first used in combat it was found that the 55 grain round fragmented and that when it exited it usually came out alot bigger than when it went in. This was just a fortunate virtue to the US Military, but they didn't engineer it to make a larger hole, it just worked out that way. The Soviets on the other hand purposely engineered an air pocket in the tip of the 5.45 bullet so that when it struck then it would rapidly destabilize and create a larger wound channel. It wasn't just a coincidence like what happened with the 5.56X45.

All in all I'd have to say that the 5.45 has some advantages to it over the 5.56X45, but other than the case angle which supposedly makes it more reliable (always a good thing) most don't do a whole lot for the end user.

1) It's cheaper to produce (steel vs. brass cased).

2) It's got a tapered case so in theory at least it's a little more reliable.

3) The case is shorter and takes less material to make it which is an advantage for the company or country that produces it, but it doesn't do a whole lot for the end user as I don't think that overall weight is affected that much.

4) This might be considered an advantage by some and a drawback by others. It's got that air pocket built into it which makes a bigger hole supposedly on it's way out so this might be considered an advantage, but that's up for debate like HS said as the 5.56 is supposed to fragment alot more and some experts believe that this is better. I think that they both do about the same damage myself. Russian soldiers who fought in Afghanistan in the 1980's were pretty impressed with the damage that the 5.45 did on Afghan rebels vs. that of the 7.62X39 round that they'd been using earlier, so it does do what it's supposed to and it is a combat proven round.

Then again on the other hand the 5.56 is supposed to be a little more accurate due to it's straight case angle, but that might just be due to the fact that most AK-74's are a little less accurate than most AR-15's as I imagine that alot of it would have to do with the platform being used to actually launch the bullets themselves. The AK reciever plays a big part in this as it flex's when the weapon is fired. I don't know what the 5.45 would do accuracy wise if it was used in an AR-15, maybe it would be just as accurate, who knows? You'd have to ask someone who owns one of those 5.45 AR's.

 

[Tomac]

The 5.45x39 7N6 is, IMHO, slightly better than M193/M855. This is due to increased reliability (tapered case as mentioned earlier) & faster yawing upon impact thus creating greater wounds on peripheral hits. The 5.56 was not designed to fragment, that was an engineering accident requiring a sufficiently thin jacket at the cannelure (ever try to get Wolf .223 to fragment?). My personal experience w/the 5.45's reliability comes from a few years back when the 5.45 SAR-2's first hit the market. I bought 2 of them and straight out of the box w/o any cleaning or lubing (just checked the bore for obstructions) proceeded to put 2,000rds of the Wolf 60gr 5.45 through each of them (4K total) w/o a single malfunction of any kind. I also decided to test what I'd heard about the bullet changing its path caused by the core sliding asymmetrically into the hollow tip upon impact. I shot a gallon water jug high center front at 50yds and the bullet exited low left rear after shredding the jug. Accuracy? I never had problems consistently hitting the 300m gongs and that was good enough for me.
Tomac

 

[Bartholomew Roberts]

Please check out Comparison of military rifle terminal effects. It shows the typical wound patterns in ballistics gel for a wide variety of military ammunition.

Just limiting the comparison to strictly military rounds, 5.45x39 is only an improvement over 5.56x45 consistency of terminal performance. It does the same thing about every time. Military loadings of 5.56x45 are a little more variable in their performance (whether they yaw and where they yaw); but when they do yaw and fragment, they produce superior terminal performance.

Accuracy wise, the 5.56mm is a tiny bit flatter in trajectory; but I don't think it is a major difference.

 

[Ash]

"The case is shorter and takes less material to make it which is an advantage for the company or country that produces it, but it doesn't do a whole lot for the end user as I don't think that overall weight is affected that much."

The case is shorter, but fatter. I imagine the total case material is the same or just about.

 

[nalioth]

5.45x39 uses a 21.456 caliber bullet

 

[max popenker]

One small note - the aforementioned 5,45 7N6 is long obsolete. The mainstay with Russian army is the 7N10 which has hardened steel core and thus is more AP'ish. It must be noted that 7N10 bullets are unmarked and cannot be easily distinguished from original 7N6
Some special troops also are issued the 5,45 7N22 or 7N24, which are true AP with hardened high-carbon steel and tungsten carbide cores respectively - these ones have spectacular performance on modern body armor, but are somewhat expensive and thus is limited issue only

 

[VirgilCaine]

Thank you for all of your replies. Very helpful.

I like consistency of performance better than occasional better performance.
See, the reason I asked is because I don't like the 5.56 round. I'd rather use something a bit heavier. But 7.62x39mm is more expensive now, and 5.45 isn't quite so bad. It sounds like 5.45 works for me.

 

[Browning]

nalioth : 5.45x39 uses a 21.456 caliber bullet.

That's not the way that it measures out with calipers.

I first heard about it in an magazine article (I think that the author was David Fortier, but I wouldn't swear to it) and I thought that it was kind of weird as well as you'd think it would be the same size or smaller, but it isn't. It's actually a little bit larger.

http://en.wikipedia.org/wiki/5.45_x_39_mm

Specifications
Case type Rimless, bottleneck
Bullet diameter 5.680 mm (0.224 in)
Neck diameter 6.248 mm (0.246 in)
Shoulder diameter 7.290 mm (0.287 in)
Base diameter 10.033 mm (0.395 in)
Rim diameter 10.008 mm (0.394 in)
Rim thickness 1.372 mm (0.054 in)
Case length 39.624 mm (1.56 in)
Overall length 56.388 mm (2.22 in)
Primer type Small rifle
Ballistic performance
Bullet weight/type Velocity Energy
50 gr 5N7 FMJ 900 m/s
(~2952 ft/s) 1316 J
(~968 ft·lbf)
Test barrel length: 415 mm (16.6 in)

These are some of the articles about the 5.45's wounding potential.

http://findarticles.com/p/articles/mi_qa3912/is_200112/ai_n9010648/pg_1

http://findarticles.com/p/articles/mi_qa3912/is_200112/ai_n9010648/pg_2

http://findarticles.com/p/articles/mi_qa3912/is_200112/ai_n9010648/pg_3

 

[SaMx]

as a civilian you can get lot's of different bullets that perform better than 5.56 or 5.45 fmj.