reconsidering 5.56mm

[justin22885]

ive been doing some testing of different types of ammo against my 75 grain HPBT hand loads in 5.56 in a few different rifles and im not all that impressed with 5.56 anymore.. giving it a best chance to perform the best it can ive learned that compared with golden tiger 7.62x39 out of my AK, not only does the 7.62x39 have better barrier penetration (obviously) but it delivers a larger permanent wound cavity on account it yaws after only about 2-3 inches, and at the absolute furthest distance i'll let a ballistics chart go it only had 5 feet more drop at 600 yards than 75 grain 5.56

also out of a borrowed 16 inch AR-15, i was getting a decent 1-1.5 MOA groups, out of my 5.56 AK-74 i was getting larger groups likely due to the 1 in 9 twist (because both the AR and AK get about 2 MOA with M855), and out of my polish AKM i used to test the golden tiger ammo i was getting about 2MOA with that ammo, so on top of everything i said in the above paragraph, the golden tiger matches M855 5.56 for accuracy and with the boat tail bullet of the GT and higher velocities, its much flatter shooting than youd expect 7.62x39 to be

so, the fact the performance of my best effort 5.56 ammo wasnt all that spectacular compared to 7.62x39, especially the GT ammo, and considering how much higher the costs are per round (30-32 cents per round for reloading components), im probably going to give 5.56 a rest and focus on the two main com block calibers of 7.62x39 and 5.45x39

since i do not have an AK-74 in 5.45, i wasnt able to test this but reviewing the data of various loads out there the almost instant yaw of the rather long cartridge gives a pretty large (matches the GT 7.62) wound cavity while the bi-metal steel/copper jacket offers better barrier penetration than 5.56, and the yaw effect is far more reliable at a greater spectrum of ranges and velocities compared to expanding or fragmenting ammunition

im not trying to convince anyone 5.56 is bad, quite the opposite i still think its a decent round, but in my personal tests of my hand loads, M855, and GT 7.62x39, i just dont believe the 5.56 is worth the effort and costs id have to put into getting it to perform where i want it to and so im abandoning that effort and probably 5.56 as well

 

[SwaneeSR]

I am curious. Could you provide more specifics on the 5.56 rifles mentioned early in your post?

 

[justin22885]

the two 5.56 rifles i used, one was an AR-15 with a 16 inch 1 in 7 twist government profile barrel, the other 5.56 rifle is a bulgarian AK-74 i built myself using an akbuilder 1 in 9 twist 5.56 barrel

 

[Lloyd Smale]

it would be pretty obvious to me even without pulling the trigger

 

[justin22885]

it would be pretty obvious to me even without pulling the trigger

what would be?

 

[SwaneeSR]

I would have thought the AR15 with the 1:7 twist would have provided good results with the heavier bullet handloads.

I have not started loading 5.56/.223 yet. Just purchased my first AR (with 1:7 twist).

Your posting goes against all conventional wisdom I have read, much on THR.

 

[Art Eatman]

Are the wound channel comparisons based on shooting critters? Such as coyotes, e.g.? I have a few coyote kills with a .223; one shot was all that was needed. (I don't doubt that the AK round would have worked equally well.)

My experience with target versions of an AR has shown sub-MOA groups. Same for my .223 bolt gun.

 

[justin22885]

the bullets were pretty accurate from the 1 in 7 inch AR-15, with the 1 in 9 twist barrel on the AK-74 the accuracy difference between the two rifles separated and its not the easiest thing in the world to find a 1 in 7 barrel for the AK-74

but the results were basically the 75 grain hornady HPBT bullets leaving the muzzle at around 2700fps for both 16" barrels, with groups around 1 MOA with the AR-15 and closer to 2 MOA with the AK.. as a control firing M855 through both rifles, both achieved around 2MOA..

its just my personal opinion that the 75 grain bullet at 2700fps with a ballistic coefficient of .395 wasnt all that much flatter shooting than the 123 grain 7.62x39 projectile that left its barrel at about 2350fps and has a reported, not definite ballistic coefficient of over .300.. taking my velocity results and the reported ballistic coefficients i found the 7.62x39 would ONLY have 5 feet more drop at 600 yards.... so my conclusion was these handloads werent ENOUGH of an improvement to make up for the added cost, but above all the extra labor when considering i like to stockpile by the thousands id rather just buy the GT ammunition than hand load thousands of rounds of 5.56 with the ballistics achieved

 

[justin22885]

Are the wound channel comparisons based on shooting critters? Such as coyotes, e.g.? I have a few coyote kills with a .223; one shot was all that was needed. (I don't doubt that the AK round would have worked equally well.)

My experience with target versions of an AR has shown sub-MOA groups. Same for my .223 bolt gun.

i do not have gel so the wound channel information i go buy is reported, documented results of ballistics gel tests, i typically dont hunt, and since my rifles are generally military style im generally not going to spend extra on heavier barrels, tighter chambers, or match triggers, 1-2MOA is fine for my goals

 

[Art Eatman]

Just personal opinion, but I think folks worry too much about "flatter shooting". I've always tried to learn the trajectory, so all I need to know is the distance.

For instance, my .223 with 55-grain SPs, zeroed for 200 yards, are right at two inches high at 100 and about five or six inches low at 300. Plenty good for prairie dogs to 300.

Punching paper, it seems to me that at known distances out beyond a couple of hundred yards, trajectory is unimportant when compared to wind drift.

 

[justin22885]

yeah, it is true and a good idea to get familiar with your rifle and your load so you can leave a zero at something like 100-200 yards and be able to get a feel for high high or low you have to hold for a target.. i was just hoping the 5.56 was flat enough to make a difference but with a 5 foot difference between it and 7.62x39 all the way out to 600 yards, 200-400 yards being more realistic and even less difference, its just not flat "enough" to justify a losing those other advantages you get with 7.62x39

i go more for energy retention at greater distances, while a 62 grain may actually shoot flatter than a 75, its ballistic coefficient is no better than 123 grain .311 bullets and starts out with about 300ft/lbs less energy to begin with, 55 grain has an even lower BC and worse energy retention.. after about 400 its basically a 22lr

 

[Coal Dragger]

If you're looking for string terminal performance in a 5.56 NATO, testing match type bullets is of limited value. There are quite a few bullet designs out there now that are quite nasty from a 5.56mm.

It sounds like you are making the evidence fit a pre determined conclusion to justify a course of action on your part. It also sounds like you have a limited understanding of long range shooting, a difference of 5-6ft of drop within less than 1K is significant....within 500 yards it is very significant. Then there is the issue of deflection from the wind, an even bigger issue since drop can be calculated and dialed easily.

Of course if terminal performance at extended ranges is what you want out of a semi-auto, you're much better off looking towards 7.62 NATO, or some of the new 6.5mm offerings like the Creedmoor, Lapua, even the .260 Remington.

 

[justin22885]

If you're looking for string terminal performance in a 5.56 NATO, testing match type bullets is of limited value. There are quite a few bullet designs out there now that are quite nasty from a 5.56mm.

It sounds like you are making the evidence fit a pre determined conclusion to justify a course of action on your part. It also sounds like you have a limited understanding of long range shooting, a difference of 5-6ft of drop within less than 1K is significant....within 500 yards it is very significant. Then there is the issue of deflection from the wind, an even bigger issue since drop can be calculated and dialed easily.

Of course if terminal performance at extended ranges is what you want out of a semi-auto, you're much better off looking towards 7.62 NATO, or some of the new 6.5mm offerings like the Creedmoor, Lapua, even the .260 Remington.

a drop of 5 feet inside 1000k may be significant if youre doing long range bench shooting competitions, not when your goals are to simply hit an 18" target

 

[69Precision]

It's not 100% clear to me exactly what your goals are. Although you seem concerned about things like gelatin results and wound channels, you say you don't really hunt. The 5.56 certainly is t the be all end all for everything, but it's very capable within the parameters it was designed for. Served on the battlefield for nearly 50 years. Great varmint round to 300 yards or so. Plenty of folks have used it for target shooting at 1000 yards. Almost no recoil. Is a 7.62x39 more powerful? Of course. And a .308 is more powerful than 7.62x39, and a 300 win mag is more power than 308.

 

[Coal Dragger]

Even on an 18" target it still makes a difference. Gives you that much more margin of error on your holds, if you are not dialing the scope. Could be the difference between a marginal hit, or a complete miss. That's just on elevation errors. Factor in wind drift, and the bullet retaining speed well enough to have a 5ft drop advantage will enjoy an even more important advantage in less wind drift. Again the difference between a marginal hit, or a complete miss.

 

[justin22885]

thats why its important to practice with the ammunition and rifle you use most

 

[bearcreek]

Take a look at this. http://tacmedaustralia.com.au/why-id-rather-be-shot-with-an-ak47-than-an-m4/ It's from a combat medic with extensive, actual, real world experience with real people, not ballistic gelatin and/or a chronograph. See if you can find anyone with real world experience with both calibers, either treating wounds from them or causing wounds/death with them that recommends 7.62x39 over 5.56x45. It's going to be a tough search, I promise you that.

 

[justin22885]

Take a look at this. http://tacmedaustralia.com.au/why-id-rather-be-shot-with-an-ak47-than-an-m4/ It's from a combat medic with extensive, actual, real world experience with real people, not ballistic gelatin and/or a chronograph. See if you can find anyone with real world experience with both calibers, either treating wounds from them or causing wounds/death with them that recommends 7.62x39 over 5.56x45. It's going to be a tough search, I promise you that.

the problem with that link is it only shows the wounding effects of one shot and it would appear to be consistent with old M43 spec 7.62 ammunition which had problems with overpenetration, more modern spec ammunition used by eastern european militaries and like what you get in the golden tiger ammo performs more like the 5.45, only larger and gives it an almost immediate yaw not present in the older style ammo

 

[bearcreek]

the problem with that link is it only shows the wounding effects of one shot and it would appear to be consistent with old M43 spec 7.62 ammunition which had problems with overpenetration, more modern spec ammunition used by eastern european militaries and like what you get in the golden tiger ammo performs more like the 5.45, only larger and gives it an almost immediate yaw not present in the older style ammo

Ok. Again, please cite someone with real world experience with both that recommends 7.62x39 over 5.56x45.

 

[Coal Dragger]

Justin22885,

Yeah you should be practicing, and guys that do will tell you that even with a lot of practice shooting at longer distances will tell you that flatter is always better, and less wind drift is always better. This is not conditional, it's pretty absolute. Not that a 7.62×39 will have sufficient precision to do much at 500 yards (much less 1K), but if it were equal to the 5.56 NATO in precision potential the flatter shooting round less affected by wind will still be better. More hits on target with a greater margin for error or shifting conditions is always better. Not sometimes. Always.

 

[CarJunkieLS1]

If you are shooting factory ammo out of semi auto rifles. For target shooting then just buy a 6.5 Grendel AR-15 it will beat the 5.56 and 7.62x39 in every aspect beats both of them. energy, trajectory, wind drift, etc.

 

[bfoosh006]

I'd be willing to bet the 77gr 5.56 load bullet... will out perform the 7.62x39 Golden tiger bullet at distances past 200yds in the terminal performance dept.

And that is what the 77gr is designed for.... better terminal performance in 2 footed critters.

The 7.62x39 is a great all around cartridge.... within certain distances.

Frankly, I am surprised by your choices in each caliber.

Kind of like comparing apples and oranges, except 2 completely different types of bullets.

 

[justin22885]

I'd be willing to bet the 77gr 5.56 load bullet... will out perform the 7.62x39 Golden tiger bullet at distances past 200yds in the terminal performance dept.

And that is what the 77gr is designed for.... better terminal performance in 2 footed critters.

The 7.62x39 is a great all around cartridge.... within certain distances.

Frankly, I am surprised by your choices in each caliber.

Kind of like comparing apples and oranges, except 2 completely different types of bullets.

the 75 grain HPBT loads i use now have more energy after about 300 yards than 7.62x39, but out to 600 yards the difference is MAYBE 50 ft/lbs when you figure the BC for the 75 grain HPBT is .395 and for the 123 grain .311 bullet its somewhere in the low .300s which isnt THAT far off.. ive already said its flatter shooting too, just not flat enough or with enough energy to make up for the other advantages offered in the 7.62x39 ammo

 

[bearcreek]

Maybe you missed my question. Can you cite any professional person who has used both calibers in combat (or at least been shot at with one while using the other) or worked on wounds caused by both, who recommends 7.62x39 over 5.56?

 

[dogmush]

What are you shooting at? That makes quite a bit of difference.

You say you want to shoot at 18" targets at a middling range. For target shooting the flatter, faster 5.56 is undeniably a better load.

You say you don't hunt, but you are worried about bullet effectiveness in tissue and barrier penetration. At 600yds.

That sounds a lot like you are trying to build up a combat against people setup. Which lots of people do. I'm not trying to call you out but it colors differently what you are weighing. Frankly, against people behind barriers, or moving, or in combat both your rounds are 300-400ish yd rounds max. That's what 60 or so years of intermediate caliber combat have taught us. For the use you describe (Barrier penetration, terminal effectiveness in flesh, 18" target accuracy and 600yd effective range) you want a rifle caliber. I use .308 for that role, but there are plenty out there.

For non fleshy targets at 600yds, the 5.56 load you describe is superior to the 7.62x39.

For fleshy targets with the calibers you mentioned you need to dial the range in a bit.