Ballistics - Involving the AK

[Drifting Fate]

but that is a well loaded SP like Laupa or Winchester. the Wolf and the likes are not consistant in accuracy.


Perhaps, it is time to get someone here at WT who is familiar with the IWBA testing processes and run a line of tests on CURRENT Russian ammo. Both so we know what we should choose as well as to stop relying on Vietnam era information to base our choices on.

That right there is issue. What we are loading with now - AR & AK - is not what was studied in Vietnam.

I'm no ballistics expert, but I keep hearing about 7.62X39 simply punching holes in people and not tumbling. My impression was that penetration was a much more significant issue in it's design than yawing was.

This subject also brings up the issue of just what AR round are we talking about? One person has mentioned the heavier bullets. If I understand things correctly, they are actually doing worse as fight stoppes because they are moving more slowly, but mostly because they are so stable that the aren't having the tumbling effect that the lighter, less stable bullets have. From a military aspect, there are advantages to a heavier, more stable bullet, but for us civilians working in an urban environment, what we want is instability.

One reason so many raid teams are going to 5.56 is the over penetration issue (when compared to pistol calibers). We shouldn't pick a cartridge just because of what will happen if we miss, but it is part of the overall equation.

Having said all that, round for round, the AK certainly has the potential to be a better stopper. I do question whether that potential has been realized to much extent, certainly not to extent it has been with the 5.56 simply due to virtually zero evolution on one hand and decades of change, testing, and tweaking on the other.

The AR works and I would even go so far as to say it is a good choice despite what it's chambered for. And, the AK is a good choice despite, or because, it's design hasn't changed much. Both do the job, and picking one over the other really shouldn't come down to terminal ballistics in a general sense. We can create scenerios for each one in which it would be a better choice than the other, but that is just gaming.

[Section1_Operations]

Well, I guess no ones referred back to all the info I've put in the AK & AR discussions.:( (I admit they need to be added to one inclusive post but don’t know if Gabe or anyone else wanted to make a “sticky” w/ the Dr. Fackler, Dr. Roberts, & the McPherson data I have.)

We're discussing a lot of differences in barrel length, velocity, and projectile construction, so let's disseminate the facts. (Gabe’s a brave man for trying to pull this all together!!!)

The current facts on 5.56mm NATO ammo is that the 55gr. M193 and 62gr. M855 loose their optimum fragmentation in the ~2,700fps +/- velocity range per Dr. Fackler & Dr. Roberts information.

The 5.56 OTM (Open Tip Match) rounds or .223 equivalents loose optimum fragmentation in the ~2,100-2,300fps +/- velocity range per Dr. Roberts information. (It seems the heavier the OTM the lower the fragmentation range goes. IIRC, the 100gr. OTM had a ~2,100fps +/- or lower threshold!)

Referencing barrel length information like SMGLee gave is the only way to know at what range Ball (M193/M855) or OTM’s will still give their optimum performance.

Fragmentation Data:
5.56mm M193 55gr. Ball w/BC .243:
~2,700fps threshold: M16 20”= 130yds, 16”= 105yds, M4 14.5”= 90yds
Neck Length: 3.88”

5.56mm Q3131A 55gr. Ball w/BC .267:
~2,700fps threshold: M16 20”= 150yds, 16”= 125yds, M4 14.5”= 105yds
Neck Length: 3.8-4.0”

5.56mm M855 62gr. Ball w/BC .304
~2,700fps threshold: M16 20”= 120yds, 16”= 90yds, M4 14.5”= 65yds
Neck Length: 3.54”

.223 Blackhills 68gr. OTM w/BC .355
~2,400fps threshold: M16 20”= 180yds, 16”= 120yds, M4 14.5”= 105yds
Neck Length: N/A

.223 Blackhills 75gr. OTM w/BC .393
~2,300fps threshold: M16 20”= 205yds, 16”= 155yds, M4 14.5”= 125yds
Neck Length: 1.57”

5.56mm Mk262 Mod1 77gr. OTM w/BC .340
~2,300fps threshold: M16 20”= 210yds, 16”= 170yds, M4 14.5”= 145yds
Neck Length: 1.60”

Russian FMJ varies from the country of origin. The older steel encased core ammo is very hard to find or rare. Therefore, most of the FMJ on the surplus market is of the lead core variety. What varies is the jacket thickness at the Ogive of the bullet so base thickness is of little use when trying to determine jacket thickness.

There’s more but I need to organize this stuff together…

[Section1_Operations]

5.56 NATO M193 55gr.


5.56mm NATO M855 62gr.


7.62 NATO M80 150gr


.308 Win. 150gr. JSP

[Section1_Operations]

7.62x39 120.5 gr.


5.45x39 53gr.


9mm 124gr. US-NATO Ball M882


.30-30 Win. 170gr. JSP

[Section1_Operations]

The performance of the 7.62x39 comes down to the FMJ construction. These are Dr. Roberts notes on the matter:

While 7.62x39 mm has the potential to offer good terminal performance when using well engineered ammunition, like the 125 gr Lapua JSP, and it offers better intermediate barrier penetration than 5.56 mm, the 6.8 mm is generally more accurate, flatter shooting, longer ranged, and demonstrates better terminal performance than 7.62x39 mm.

There is a bit of a controversy brewing in some of the AAR’s coming in from OCONUS on the effectiveness of 7.62 x 39 mm ammunition. Initially, this appears somewhat strange, as there may be more forensic data available regarding wounds caused by the Russian 7.62 x 39 mm FMJ than for any other rifle cartridge.

The original 7.62 x 39 mm Russian M43 Type PS 120.5 gr FMJ boat-tail bullet has a copper-plated steel jacket covering a large steel core. WDMET (Wound Data and Munitions Effectiveness Team) collected extensive forensic data on over 700 7.62 x 39 mm gunshot wounds during the Viet Nam war. The predominant feature of this cartridge is the MINIMAL amount of damage it produces in soft tissue wounds, on par with FMJ handgun wounds such as those produced by 9 mm M882 ball.

We also have extensive law enforcement data, as this cartridge has been used extensively in illicit activity. For example, in the 17 January 1988 Stockton school shooting, 30 of 35 kids shot lived. Of the five that died, all were shot in critical structures—head, heart, spine, aorta and none had damage to any organ not directly hit by a bullet.

However, not all 7.62 x 39 mm FMJ bullets are of the original steel core construction. Significantly increased tissue damage is produced by the early yaw seen with several 7.62 x 39 mm FMJ lead core bullets, including:

-- Yugoslavian M67 124 gr FMJ, flat based, copper-jacketed, lead core bullet which travels only 3.5" in tissue before yawing

-- Chinese (PRC) 7.62 x 39 mm 123 gr FMJ, copper-jacketed, lead core bullets which begin their yaw after only 2-2.5" of travel in tissue.

-- Czech and several types of Western commercially produced lead core 7.62 x 39 mm FMJ yaw within the first 2-3” of travel in tissue.

In both uncomplicated extremity and torso wounds, the very early yaw of these lead core 7.62 x 39 mm FMJ bullets allow the projectiles to travel sideways through the body, increasing permanent tissue destruction and temporary cavitation effects compared to the standard 7.62 x 39 mm Russian M43 Type PS 120.5 gr FMJ. These early yawing lead core 7.62 x 39 mm FMJ bullets cause wounds very similar to the 5.45 x 39 mm Russian M74 53 gr FMJ bullets.

The yaw cycle is related more to the projectile's shape and CG than it's linear velocity. As Fackler's work illuminated, pointed rifle bullets will yaw even at very low velocities.

There is no standard answer as to if and when a 7.62 x 39 mm bullet will yaw. With the original Soviet M43 Type PS 120.5 gr steel core FMJ, the bullet tends to drill right through the average human torso without yawing or fragmenting, resulting in relatively minor wounds as long as no critical structures are directly struck by the bullet--this bullet eventually exhibits a bi-lobed yaw cycle as depicted in the first wound profile above. The lead core 7.62 x 39 mm, such as the Yugoslavian M67, PRC lead core and American commercial lead core 123 gr FMJ’s begin to yaw after only 2-4" of travel in tissue, causing significantly greater permanent and temporary cavity effects, similar to those caused by the 5.45 x 39 mm M74 53 gr FMJ bullets fired by the AK74 as depicted in the second WP above.

At this time, the 7.62 x 39 mm load offering the best terminal performance is the Winchester 123 gr JSP (X76239): pen=15”, RD = 0.56”, with approximately 25 to 30% fragmentation and NO yaw--think of it like a 125 gr .30-30 load.

In a CQB setting, the 6.8 mm OTM and PT will fragment and are unlikely to exit the torso; the 7.62x39 mm SP's tend to retain their mass and are very likely to exit target. Both will work, although I would prefer the 6.8 mm for this settting. I am looking forward to trying the 7.62x39 mm PT later this month to see if it will be a viable choice for CQB.

Don't apologize!!! We were also excited to test it. The strange thing, was that it did not particularly offer good terminal performance in either 7.62x39 mm or .308. The 150 gr BT is clearly a better .308 bullet. Likewise, I think I would stick with the Win 123 gr JSP, the Saspan/Uly 124 gr JHP, or the Lapua 125 gr JSP.

Before making any final determination on the Saspan/Uly 124 gr JHP load, intermediate barrier testing, including auto windshields, as well as some accuracy and reliability testing needs to be completed. Nontheless, in this prelim eval, it looks good.

The Lapua 125 gr JSP proves to offer outstanding terminal performance!

Out of a 16” barrel:
Bare Gelatin: vel=2316 f/s, pen=17.3”, RD=.62”, RL=.43”, RW=122.6 gr
Car Windshield: vel=2323 f/s, pen=14.8”, RD=.60”, RL=.40”, RW=110.6 gr

Performance is similar to the Trophy Bonded Bear Claw bonded JSP bullets used in the Federal Tactical loads, with deep penetration, excellent expansion, and good weight retention. Because of the larger permanent cavity and greater bullet mass, the Lapua 125 gr JSP will offer somewhat better performance than the .223 bonded JSP’s. This load will be a good choice for LE use against car windows and should also be outstanding for hunting deer and other similar size game.
(Thanks to "boyanzhu" for making this test possible.)

The Lapua load appears to feed just find in an AK, I don't know about the SKS. The ones we pulled measured 0.310" and have a cannelure.


Winchester 123 gr JSP (X76239) in Bare Gel:
vel=2253 f/s, pen=14.4”, rd=0.56”, rw=90.1gr

Pretty much the same results when going through car windshields.
Have not shot the Nosler 125 gr bullet in 7.63 x 39 mm.

[Paul Gomez]

Guys,

I'm just crawling into my hidey-hole after the Glock Summit, once I've gotten some rest, I'll jump in with some info.

I have spoken with some people about doing tests on currently availalbe ammunition. Additionally, I have some pics of sectioned rounds of ammunition that do a very nice job of illustrating the differences between various sorts of 7.62 x 39 ammo.

[Section1_Operations]

Gomez-

I expect to see additional testing soon from Dr. Roberts on all cartridges this is what I have of the last rifle data specific to 5.56/7.62x39. I know Dr. Roberts was going to be testing some additional 7.62x39 rounds from Corbon, etc..

.223 Blackhills loaded Nosler 60 gr Partition JSP:
Fired from a 16” 1/7 test weapon
BG: vel=2685f/s, pen=18.5”, Max TC=11.5 cm @ 11.5 cm, RD=0.41”, RW=52.5gr
Auto windsheld: vel=2757 f/s, pen=18.9”, RD=0.32”, RW=35.4gr

Notes: The .223 BH loaded Nosler 60 gr Partition JSP has been recommended as a barrier load; while it performs better than most .223 loads, it is not as good as the 55/62 gr TBBC bullets for intermediate barriers and should be considered a distant second place.

7.62x39mm Saspan 124 gr JHP (Ulyanovsk Machinery Plant):
Fired from 16” AKMS test weapon
BG: vel=2297 f/s, pen=15.0”, Max TC=10cm@18cm, RD=0.63”, RW=100.5gr

7.62x39mm 125 gr Nosler Ballistic Tip from Georgia Arms:
Fired from 16” AKMS
BG: vel=2174 f/s, pen=20+”, Max TC=7cm@8 cm, small diameter TC and poor fragmentation pattern resulted in sub-optimal terminal performance. Excessive flash and dirty powder. Note--load is advertised as "2400 fps".

7.62x39mm 154 gr Wolff JSP:
Fired from 16” AKMS
BG: vel=2257 f/s, pen=20+”, Max TC=7.5cm@10cm, unexpanded lead core exited block.

Notes: The 7.62x39mm loads offered the most disappointments of anything tested. The 124 gr Saspan/Ulyanovsk JHP was the only 7.62x39 mm load in this test which offered acceptable terminal performance. We had hoped the 125 gr PT load would bring the 7.62x39mm up to 6.8 mm type performance--it does not.

[ccwinmemphis]

When I talk with people that have actually seen people shot with 5.56 mm, either in law enforcement of in the military, they invariably describe very nasty wounds and potent stopping power. I was just talking with a previous SWAT captain in Memphis who was describing the results when several drug-dealing gang members were shot with 5.56, and he said the chest wounds were large and immediately effective. I am quite confident with a 16" AR shooting 55 grain ball in XM193 or Q3131. Within 100 - 150 yards, I bet this will equal or exceed the terminal effectiveness of the slower non-fragmenting AK rounds. The fact that there is less barrier penetration is an advantage for my anticipated uses. As I've said here before, if I want penetration, power, and distance, I'll pick a 308. In my opinion, there is nothing an AK does better than 223 or a 308 except save money on the firearm purchase itself.

I'de love to hear from more people who have actually seen the results from AK and/or AR rounds used in actual shootings.

[Section1_Operations]

IMO, shoot the weapon you have and who cares about all the cartridge debate.

If you have an AK buy 1,000rds of a Lapua or Winchester JSP to guarantee all the performance you can in a defensive rifle. (30rd box magazine fed .30-30!)

If you have an AR and want the barrier capability of the 7.62x39 then buy 1,000rds of a JSP. If you want to extend and guaranteed fragmentation to the maximum range buy 1,000rds of a good OTM. (Cover both and split it with 500rds of each)

None of the realistic ranges a civilian will engage at are likely to come close to the maximum cartridge envelope for effective fragmentation. And both cartridges remain cheap to shoot with FMJ and in the end FMJ is better than nothing.

I don’t need to go and spend $500+ worth of investment into another system when I can spend that on ammo and get the exact same performance.

People seem way too caught up in the cartridge performance when they should really focus on the necessary skill set required to effectively deploy a rifle in CRG or extended survival situation.

[LMGBeliever]

Have seen a bunch of KIA and WIA on both sides from these calibers, so here goes. 5.56mm in the 20 inch m16A4, is a decent manstopper in the hollowpoint variety (blackhills 77 grain) it would fragment, and is the round of choice for a lot of us. Sweet. Stopping power is reduced from the m4, but mostly at longer ranges is the m4 less effective. Moral of the story, tailor your weapon to your mission, it's easy. The "green tip" 5.56mm sucks, period. Guys soak it up and can survive. I have seen headshots, through the eye, that didn't kill people.

The 7.62 can tear men up. Hits to extremities usually brought about a crippling process, as in my shoulders shattered and I can't use it. If it hits just meat, it's not going to do anything. Just like any other bullet. I have also seen 7.62x51mm just skimm around a person's skull. Bullets do strange things, and luck plays a huge factor.

My short answer to this whole process would be, use good ammo, only solid hits count, and tailor your weapon to your mission.