7.62x39 vs 5.56 vs 5.45x39

[Polie]

I found these soft tissue profiles and was REALLY surprised:







Ok before I start PLEASE for the love of God do NOT start the "The AK is better than an AR because..." or the "The AR is so uber tacticool and much gooder than the AK because...". No one gives a flying monkey fuck. One can pull up 1000 youtube videos of AR's or AK out preforming the other.

I just thought some of you guys might like this. It seems for 2 legged critters they seem just about equal, with no armor of course. It seems that the 5.56 would be the BEST choice for not over penetrating as the 7.62x39 and the 5.45x39 over penetrate when considering two legged critters. For hunting it seams that the 7.62x39 would be the best option of the 3.

Anyways this may have just turned me form an AK SBR to an AR SBR now!

[Doctorr Fabulous]

1. Overpenetration is BS. USe better quality ammo, the surplus stuff is for practice.
2. Use better quality ammo. Compare Mk262 77gr OTM (designed to be magic-killer-super-awesome out of a 10.5-14.5" barrel, but still awesome out of a 20") to M855 ball. Mk262 wins every time. Same goes for surplus x39 ammo vs the Hornady SST loadings.
3. Didn't we already have a discussion about the mostly-myth of overpenetration?

[Troy Adam]

Very interesting info. Thanks for posting Polie.

[thechin]

1. Overpenetration is BS. USe better quality ammo, the surplus stuff is for practice.
2. Use better quality ammo. Compare Mk262 77gr OTM (designed to be magic-killer-super-awesome out of a 10.5-14.5" barrel, but still awesome out of a 20") to M855 ball. Mk262 wins every time. Same goes for surplus x39 ammo vs the Hornady SST loadings.
3. Didn't we already have a discussion about the mostly-myth of overpenetration?

Against a hard target (wearing armor) overpenetration would not occur with a 5.56 round out of a standard M16 rifle length 20" barrel. Definitly would not occur with anything shorter. Unarmored? It's possible (doubtful), maybe depending upon how husky the target is. Chart is showing penetration 30cm to 65cm. You have to think about exactly how much lenght is there from your belly button to your spine (35cm to 45cm maybe?)

[azrael99]

i read somewhere that at less than 100m there is not significant difference between the X39 and the 5.56 either in accuracy or kinetic energy. and mostly in short barrel weapons since the round didn't get it full acceleration .

someone can confirm that ?

[Doctorr Fabulous]

1. Overpenetration is BS. USe better quality ammo, the surplus stuff is for practice.
2. Use better quality ammo. Compare Mk262 77gr OTM (designed to be magic-killer-super-awesome out of a 10.5-14.5" barrel, but still awesome out of a 20") to M855 ball. Mk262 wins every time. Same goes for surplus x39 ammo vs the Hornady SST loadings.
3. Didn't we already have a discussion about the mostly-myth of overpenetration?

Against a hard target (wearing armor) overpenetration would not occur with a 5.56 round out of a standard M16 rifle length 20" barrel. Definitly would not occur with anything shorter. Unarmored? It's possible (doubtful), maybe depending upon how husky the target is. Chart is showing penetration 30cm to 65cm. You have to think about exactly how much lenght is there from your belly button to your spine (35cm to 45cm maybe?)

Well, if you use ammo designed to penetrate armor, you might have a slight issue, although there are some other things to consider: 5.56 and 5.45x39 are designed to yaw wildly with he 55gr and 62gr M855 rounds. It won't be a straight clean shot through and through. Other things missing are the media, method of testing, and the barrel length of the weapon firing it. Ballistic gellatin is great to test penetration, but it doesn't tell you squat really about how the round will behave in actual flesh, blood and bone, other than giving you a visual aid of "this is how it would fragment and travel in a 100% homogenous substance that sort-kinda acts like flesh.

But back to round choice: Don't use M855 for defense unless you think you're gonna go head to head with people a lot better equipped and trained than you. Off the top of my head, there are seven different loads I would choose first: 77gr Sierra BTHP, 77gr Nosler BTHP, Hornady 75gansta, Mk318 OTM, 55rg XM193, Hornady SST 62gr, Hornady 69gr are all better choices, assuming you match the load to your barrel length and spin. 1:7 should stabilize all of the above well enough for anything under 300yd, although I haven't tested it myself.

For the Rusky ammo, everything but the commercial JSP was FMJ, which leads me back to my initial advice: use better ammo. Use ammo designed to be used for heart and lung shots to drop the target as quickly as possible, and then practice (get training) so you can put them there.

Lastly, there's the matter of energy remaining: how much energy does the round have after it leaves the target? Call of Duty=/=the real world, you can't drop 2 guys standing ten feet apart with a single 7.62x39 delivered COM just by lining them up, especially if you get ammo designed to be used against unarmored targets.

If you really think you're gonna face off against guys with plate carriers, move. You won't win that battle more than once or twice.

[thechin]

I just went to firearms tactical and realized that the above charts are from the mid 1980s. M193 FMJ was fired out of a M16A1 and the M855 FMJ out of a M16A2

Just food for thought, check out the differences between the 7.62x51mm M80 FMJ (Fired from M14 rifle):



and the .308 Winchester 150gr JSP

[Regular Guy]

In reference to docs comments. All of the rds he mentioned work and group very well out of a 1/7 brl. The furthest I've shot them is 300m but they easily stay in a 6" group.

7.62x51mm fmj generally stinks. But the soft tip and ballistic tips are absolutely devastating.

[Polie]

I see mostly 1/9 barrels for 12" pistol uppers, but maybe I am not looking hard enough. lol I was not taking in account reloading ammo, only because the time vs cost of cheap bulk ammo right now is/was good. I have a LOT of 7.62x39 which is the only reason I am still leaning towards a ak. (unless I find a cheap'ish 7.62x39 pistol upper lol)

[Doctorr Fabulous]

I see mostly 1/9 barrels for 12" pistol uppers, but maybe I am not looking hard enough. lol I was not taking in account reloading ammo, only because the time vs cost of cheap bulk ammo right now is/was good. I have a LOT of 7.62x39 which is the only reason I am still leaning towards a ak. (unless I find a cheap'ish 7.62x39 pistol upper lol)

Bulk ammo for training and practice is one thing, but using bulk FMJ or surplus/overrun M855 foe defense is kinda dumb. On top of that, a 10.5" or 12.5" SBR will have a much different ballistic profile than a 20" barrel.

Question: your CCW is probably a 9mm, .40, or .45 pistol, no? Do you use cheap bulk FMJ for daily CCW? If so, feel free to ignore all of my posts on the topic. If not, and liek me you practice with cheap FMJ, but carry a hollowpoint of some description, then why would you use cheap bulk FMJ for the SBR? Hell, even XM193 and mk318 SOST do nasty things out of an SBR with devastating terminal ballistics, and I really doubt either is going to leave the target with enough energy left to hurt anything. Pick your twist based on the barrel length, and pick the platform based on more than just what has the cheapest bulk ammo. I remember about 6-8 months ago there was mk318 selling for $.50/round, which is enough to stock up 500 or so for "real" use, and then just use XM193 for practice.

[UndeadInfidel]

Awesome job using data so old it had to be drawn by pen and paper.

Go find some drawrings of modern 5.56/.223 high grain soft points.

[Doctorr Fabulous]

http://ammo.ar15.com/

Take a look there...There's a gel test showing 13" of penetration by Mk262.

[Alpha-17]

I always find it funny that M193 is recommended as if it was some magic bullet the US military and NATO forgot about. In reality, it had the same issues that M855 had. While the 5.56 round did get a reputation in some circles for causing massive wounds in Vietnam, in other circles it was regarded as poodle-shooting round (sound familiar, huh? Guess somethings never change). For instance:

“In 1980, I treated a soldier shot accidentally with an M16 M193 bullet from a distance of about ten feet. The bullet entered his left thigh and traveled obliquely upward. It exited after passing through about 11 inches of muscle. The man walked in to my clinic with no limp whatsoever: the entrance and exit holes were about 4 mm across, and punctate. X-ray films showed intact bones, no bullet fragments, and no evidence of significant tissue disruption caused by the bullet’s temporary cavity. The bullet path passed well lateral to the femoral vessels. He was back on duty in a few days. Devastating? Hardly. The wound profile of the M193 bullet (page 29 of the Emergency War Surgery—NATO Handbook, GPO, Washington, D.C., 1988) shows that most often the bullet travels about five inches through flesh before beginning significant yaw. But about 15% of the time, it travels much farther than that before yawing—in which case it causes even milder wounds, if it missed bones, guts, lung, and major blood vessels. In my experience and research, at least as many M16 users in Vietnam concluded that it produced unacceptably minimal, rather than “massive”, wounds. After viewing the wound profile, recall that the Vietnamese were small people, and generally very slim. Many M16 bullets passed through their torsos traveling mostly point forward, and caused minimal damage. Most shots piercing an extremity, even in the heavier-built Americans, unless they hit bone, caused no more damage than a 22 caliber rimfire bullet.”

Fackler, ML: “Literature Review”. Wound Ballistics Review; 5(2):40, Fall 2001

Got the quote from here:
http://lightfighter.net/eve/forums/a/tp ... 8320859863

Goes to show that both M193 and 855 can suffer from the same problem. If you want a "magic bullet" in 5.56, Mk262, MK318, or another HP or Ballistic tip round will have to do.

[Doctorr Fabulous]

“In 1980, I treated a soldier shot accidentally with an M16 M193 bullet from a distance of about ten feet. The bullet entered his left thigh and traveled obliquely upward. It exited after passing through about 11 inches of muscle.

Both my parents were shot in the face or upper torso at a range of <10 feet with a 9mm. Shooting a guy in the thigh is not a lethal shot unless you clip the femoral. Also, doesn't XM193 perform best with a 1:12 twist? I seem to remember a few pics on this site of a guy(s) shot at under 50m with XM193 and showing MASSIVE trauma in non-lethal areas that certainly stopped them from moving.

Perhaps what you meant is that there is no magic bullet, and the only way to be sure of a killshot is to make 30 of them in the center of the vital organs. Expanding ammo helps greatly though, and since an SBR is being discussed, I'd go Mk262 for a 5.56, since it was designed for use in 10.5-14.5" barrels.

ETA: my parents survived, and both the bastards involved got sentenced under under .fed law for stealign a bunch of NFA and other firearms...and attempted double homicide. Just think, my siblings and I were a few inches and some shitty bullets away from being a trio of Punishers/Batchildren...

[We'reWolf]

“In 1980, I treated a soldier shot accidentally with an M16 M193 bullet from a distance of about ten feet. The bullet entered his left thigh and traveled obliquely upward. It exited after passing through about 11 inches of muscle.

Both my parents were shot in the face or upper torso at a range of <10 feet with a 9mm. Shooting a guy in the thigh is not a lethal shot unless you clip the femoral. Also, doesn't XM193 perform best with a 1:12 twist? I seem to remember a few pics on this site of a guy(s) shot at under 50m with XM193 and showing MASSIVE trauma in non-lethal areas that certainly stopped them from moving.

Perhaps what you meant is that there is no magic bullet, and the only way to be sure of a killshot is to make 30 of them in the center of the vital organs. Expanding ammo helps greatly though, and since an SBR is being discussed, I'd go Mk262 for a 5.56, since it was designed for use in 10.5-14.5" barrels.

sorry to hear that

[wguy00]

ETA: my parents survived, and both the bastards involved got sentenced under under .fed law for stealign a bunch of NFA and other firearms...and attempted double homicide. Just think, my siblings and I were a few inches and some shitty bullets away from being a trio of Punishers/Batchildren...

Dude, that sucks and I feel your pain. My dad was shot in the face with a revolver a few years ago. The cops said it was some sort of gang initiation (for the shooter, not my dad). Apparently it was a BIG revolver and the kid had it pointed at my dad's temple. When he pulled the trigger, he went off target and ended up shooting him in the jaw. That was the second time he had to have his jaw wired shut. At least our parents are still alive man.