.

Define "punch".

The question that you are asking does not have a simple answer. You need to define exactly what you mean by "punch" and "penetrating power".  For example do you mean kinetic energy or momentum?

If you are talking about maximum penetration, here are some things to consider. The ability of a bullet to penetrate is controlled by impact velocity, bullet construction and sectional density. For example solid non-expanding bullets are often used on large dangerous large game (i.e. elephants and water buffalo*) because they do not deform and generally offer maximum penetration into the vitals of a large body animal.

Given two bullets of similar construction and at similar velocities, the bullet with a higher sectional density will tend to penetrate deeper than a bullet  with a lower sectional density.  

* I am not suggesting that any of the calibers that you list are considered adequate for hunting these animals.

320pf

358WSSM.......... that'll have some punch, but I prefer beer  

7.62X39 has punch, 5.56 has zap, Grendel has Shazam! 6.8 has vaporage.

Just add them all together and divide by five.

ETA-the answer is 6.82x40.Rim size is .4136.Bullet gr in 104.8.velocity 2500 fps.

-everything is starting to converge on the 6.8 spc (lightly loaded)

-considering more 6.8 availablity over 6.5 and 300 whisper the 6.8 would offer more bang per buck(all things equal)

energy figures also favor this round with the greatest case capacity and second largest bore.

I'm betting 6.8 spc.

If you could hybridize the 6.5 and 6.8 I would say a 124gr 6.8 in a 41mm grendel case at 55k psi.Bolts might die a quick death though.

Lets just put it this way best all around bullet is the 6.5 I mean you get 1 moa at 600 yards and it has the most close range stopping power, second best all around bullet is the 5.56 after that then 6.8 but after 400 yards it is pretty worthless.. the 5.56 will still get you to 1000yds and has CQB stopping power.. alot of people have never used the 5.56 for self defence or in the military on these forums and just go buy what other people say and there are people that say the 5.56 sucks then people that say its the best all around AR round you can get.. the people that say that are the better shooters..

Most if not all of those cartridges will do 1 moa @ 600 yards.  Comparing them all being shot from the same quality of barrel and bullets balances thing out a bit.  

The 6.8 is far from worthless after 400 yards.  If you don't beleive me stand at 600 yards and let someone shoot at you with it.  Heck I'll make it 700, even 800 if you promise not to move around to much.  

Not sure where you come up with the 6.5 has the best stopping power.  


The people that wanted and created th 6.8 were people that were using the 5.56 to shoot people with much more then just about anyone and they felt the 6.8 was needed.  Last time I checked most of the 5th group guys were fairly good at hitting what they aimed at.  

As for most of the people on here not having shot someone so they have no way to know and can only go off of what they are told by others:  How else would you suggest they decide what to shoot?  I think by looking at the huge amount of testing that has and is still being done and making a decision based off of that sure sounds like a sound idea.  All of that along with a long history of the 5.56 performance out of shorter then 20 barrels along with the various ballistic gel and barrier testing all show the 5.56 to be at the end o the line.  Concluding a person should use less just because if you are lucky enough to hit your target in the right place it works is flawed logic IMO.  Last time I checked even mil trained people don't have great luck with perfect hits when people are shooting at them let alone a less train civy.  I would think you would not want what might be barely good enough and get every advantage you could in the area of wound damage.  The statement that the people that say the 5.56 is the best cartridge are the better shots simply defies logic and common sense. SO a person that think there is a better round then the 5.56 must be a bad shot.  That is so preposterous its laughable.  SO wanting a proven more effect cartidge makes you a bad shot hmmm.

In testing of the various mentioned calibers the 6.8 has show to have the best wound profile of them for human targets.  Now bullet design certainly plays a large part in this as well but those are the facts as tested.  

On paper or ballistic program? Honestly I don't know, run the numbers yourself.  For my money? 6.8spc.  I don't shoot at things over 300 yds away. I have a gut feeling that most people that post these kinds of questions on internet forums don't shoot at things over 300 yds. away either.

at shorter ranges, the big bores like .50 beowulf, and .458 socom have the most energy. the 7.62x39 will also the next highest energy at short ranges. but be careful as most cheaper bullets suck in this caliber. wolf MILTARY CLASSIC JHP will fragment quite well though.

when you get out farther the 6.8 overcomes the 7.62x39. pretty damn quickly actually. however out past 400+ yard, the 6.5 retains slightly more energy as well as a flatter trajectory, over the 6.8

300 whisper is really for supressed rifles, and 5.56 is "usally good enough" in fragmentation ranges (under 200yds with m193/m855), but is clearly surpassed by the other rounds.

Try Hornady.com, it has a program. You enter cal. bullet weight, and speed. This will give a H.I.T number. The higher the number = more punch.


Mike  

The big bores will not fly far???
Battle of Adobe Walls Article  While the distance is in dispute, it appears that it was at least 1,000 yards with a 50 Sharps ...

.45-70 at 2 miles - link to archived thread copying article from elsewhere

Since one of the test's objectives was to gauge bullet penetration, the huge target consisted of three 1-inch thick boards, separated by 1-inch cleats. The target was supported on 6-inch spruce posts and was constructed partly of spruce and partly pine, since this was the wood at hand.

In the tests at 2,500 yards, the target was hit five times in seventy rounds with the .45-70-405 service load, only once with the Martini-Henry in eighty rounds, and four times with the long range Springfield in thirty shots.

When the Springfield long range cartridge was fired, the 500-grain blunt nosed lead bullets propelled by 80 grains of black powder in the 2.4-inch cases at about 1,375 fps penetrated right through the three inches of wooden target and buried themselves in the sand. One 500-grain slug pierced three inches of target and buried itself in a supporting six-inch post, giving a total penetration of a measured 5.25 inches. The Service 405-grain bullet gave a penetration of just 1.12 inches, and the Martini-Henry 480-grain bullet, 2.50 inches.

338 Spectre in a 10.5" barrel, firing a 300 SMK subsonic, penetrated 7 layers of 2" pine and then pierced a 1-gallon metal paint can ... BigBore of ADCO did the tests.

7.62x39 will outpenetrate 6.8 spc by far.

THANK YOU MARTY!!!!  I keep trying to get this across to people how deadly and long range the .45-70 and additionally the .458S and .50B bigbores really are!  People have been dropping frigging buffalo out west with .45-70's and .45-90's for what, like 150yrs or something silly like that?!?! And at EXTREME ranges!!!  I am not saying that I personally am going to take my .50B with it's 16" barrel and try and drop a deer at 300yds, but the capability of the big bores is largely downplayed, for some unknown reason.  Pick the right bullet (probably NOT a hollow point) and get the muzzle velocity up there a bit, and they will still have a lot of energy at long ranges.

With that in mind, I'll take my 6.5x55 Swede with a 140gr SMK any day...  

This may help at least with a few of these.  I first killed a Hog 250lbs head shot with a .308.  Then I stood 50yrds away and with a friend shot it with a 5.56 fired out of a LMT MRP 16", then a .308 Fired out of a HK91 16" as well.  Out of the AR I fired 40gr, 55gr, 77gr.  Out of the HK91 I fired 150gr, 168gr, 180gr.  All of the bullets were shot down the line to get an idea of the effectiveness.  At the distance I was shooting at the 55gr, and 77gr preformed very well, and I feel confident they would stop a Hog with one shot center mass.  As for the .308 I believe a shot damn near anywhere would get a kill!  The 150gr was in and out not shocking it was a FMJ, the 168gr punched a pretty good hole, and had very nice expansion judging by the back side.  I found that the 180gr preformed the best in my little test sort of...  It really did alot of damage, and if it had been a deer I'm not sure how much meat would be left.  

Quoted: Quoted: 7.62x39 will outpenetrate 6.8 spc by far. Got hard data to back that up?

Just find a ballistic table. It's all there man. Hornady has a good one.

7.62 versus 6.8 its all about bullet construction and velocity.  Put up a test showing a bullet hat is specifically designed to have limited penetration in a test that was showing that other cartridges popular bullets either over or under penetrates not conclusive of anything.  The 6.8 bullet did what it was designed to do.  Make that a FMJ or better yet a AP and beleive me that bullet will penetrate much deeper then many people realize a bullet will go.  At a recent LE sponsor shoot on of the 6.8 uses was shooting at the target automobile the TSX bullet completely penetrated both car doors and kept going.

DocGKR has been saying for some time that the weight of the bonded bullet used for the 6.8 needs to be much lower as it is significantly over penetrating.  They are 110-115 and they need to by 90-100 grain to lower the penetration.  The TSX proves this out.  You want to kill whats in the car not have it go in the car thru the perp/combatant and out thru the other car door and into a bystander.

The 6.8 flys flatter, farther, and with higher velocity then the 7.62x39.  As far as more energy at closer range again that is the effect of bullet weight and speed .  
It is also incorrect that the 7.62x39 has more energy at closer range.  You have to compare apples to apples. The 6.8 can push the same weight bullet faster the the 7.62x39 so it will have more energy as well.  Even the 155 gr  7.62x39 load versus the 130 speer sp in 6.8 and the 6.8 will still win in energy at the muzzle.

I've never seen a 6.8 SPC fmj gel test but I can almost guarentee it would not penetrate as much as a 7.62x39 fmj.  Would be great to see though.