The great 6.5mm vs. .308 Bullet Debate, but with TERMINAL BALLISTICS

NevadaZielmeister

Sergeant
Full Member
Minuteman
Mar 1, 2013
694
14
Northern Nevada
Gentlemen,

Does any one have any knowledge, data or links regarding the terminal ballistics between these two bullets? When I say "terminal ballistics" I mean this definition: Terminal ballistics - Wikipedia, the free encyclopedia = "the study of the behavior and effects of a projectile when it hits its target."

I get that the 6.5 mm or even 6.0 mm bullets have better ballistics coefficients and perform better at longer ranges over the .308 (I have personal experience myself), but what about when they actual impact a soft bodied target, such as an animal or even a person? Are there any ballistic gelatin tests between the two? Is a bigger hole more devastating? Is more mass better or do you want more speed?
 
NevadaZielMeister,

I've killed a lot of game with the .308 and 6mm's. The .308 definitely puts animals down harder.
Still, given identical placement I doubt you'll see a lot of difference in total outcome. I still vote for the .308, tho'.

Wes
 
Either of them will kill deader than hell. It's going to come down to the individual bullet and the impact velocity as to what the terminal performance is. Heavier bullets of course are going to penetrate further at equal velocities.

I'm not sure which .30cal bullets you've been looking at but there are bullets with better BC's than anything 6.5mm. Anything 200gr+ from Berger has a higher BC than the highest BC 6.5mm bullets. The .743 BC of the 230gr is just plain retarded, run the numbers of that at 300WM or 300RUM velocities and you'll probably change your tune about .30cal ballistics.

Are you interested in hunting with these calibers? If so what animals?
 
Seeing how much more often I hit a target shooting a 260 Rem verses a 308 Winchester, I have found it wise to turn this question around.

"What is the Terminal Ballistics of a missed shot?"

Thats why I do take a 140 over a 168, 175, etc. EVERYDAY of the week!
 
Weshowe you have not fired the 6.5 saum. It simulates a grenade shot from inside the animal. Might want to try one, ask Pat Sinclair. I have fired many large calibers and this little round hits pretty dang hard. I parked my 300 wm and 7wsm in favor of the 6.5 shooting little 130 gr vld's.
 
My wife dropped a 350lb black bear in its tracks at 450yds with a 140 berger in a 260. Ive had much better results with the 6.5 and 6mm bullets on game due to velocity. Ive lost several coyotes with solid hits from a 308. Yes 30cal bullets will do the trick in 300 rums and such but on most deer size game they are way over kill. The 6mm and 6.5s placed in the kill zone will drop most big game no problem. Biggest thing is bullet selection. I dropped an elk with a 243 with a through and through shot through the lungs. My uncle just about lost an elk (took a whole day to find) that he shot with his 300 rum. He was using a 185 berger at 3300fps and the bullet exploded on the skin the size of a softball but only went in an inch.


Sent from my SCH-I605 using Tapatalk
 
Good bullet thru vitals = death
Anymore ?'s

The only situation in North America that I would feel inept w/a 6.5mm is a Grizzly at close range charging. I would pop any moose, elk, etc. to 400 yds, deer further.
They cannot survive after you take their lungs out.
 
I have seen this in a number of recent topics, where someone says ".308", and the discussion runs all over the place.

Needless to say, there is a big difference between a ".308 Winchester" and a ".30 cal bullet". Per above, are you shooting a 175 grain out of a .308 Win, or are you shooting a 230 grain out of a large .30 cal magnum?

Also "Terminal Ballistics" is obviously not the same as "Shot Placement".

If you want to truly evaluate a number of different rounds in terms of Terminal Ballistics, then you need to make sure that you are doing a true apples to apples comparison.

There are a number of variables / issues to look at when it comes to Terminal Ballistics:
Range - a number of bullets and the round pushing them will perform very similar at close range, but some of them will do much better than the others at longer ranges.
Bullet Type - Terminal Ballistics is about transferring energy to the intended target. While some bullets my do extremely well in terms of BC / External Ballistics, they do not do well at transferring energy into the intended target.
Target - Terminal Ballistics has a lot to do with the makeup of the intended target, and how the bullet will interact with it. The bullet needs to have the correct amount of penetration and expansion to transfer as much energy as possible and perform as intended.

If you want to really get into Terminal Ballistics, there is a lot that goes into it, it is not just a determination based on a single variable. If you want to try and do some calculations and fair comparisons, then you need to nail all of those down.

Sorry that is not a straight forward yes or no, but it will hopefully get things heading in the right direction.
 
Tell that to 240gn SMK ... SD=.361

240 out of a 308? your looking at 2400fps +-
being a SMK, and that slow, its a 98% chance it will not expand in the slightest... and will FMJ your target

in contrast, the 160gr interlock 6.5 in a 260 is 2650+- and will expand
Sectional Density0.328

<tbody>
</tbody>


Hornady160grRNSP.jpg
 
Last edited:
240 out of a 308? your looking at 2400fps +-
being a SMK, and that slow, its a 98% chance it will not expand in the slightest... and will FMJ your target

in contrast, the 160gr interlock 6.5 in a 260 is 2650+- and will expand
Sectional Density0.328

<tbody>
</tbody>

Don't we all like to tailor examples for our needs, nobody said anything about 308 winchester, next thing you know we are puking 125s out of a Whisper ....launch that 240 from WM or RUM see what happens.
 
Last edited:
well the OP says 308, not 30cal class.

but even still, i would NOT use a SMK to hunt with, sure, under 300y, it "may" open up, i have have seen WAY too many 168smk's NEVER open at 100-200y to never trust them for hunting. the only "match" bullet i would trust for that would be a AMAX
ive seen the 123AMAX expand on a 8" thick groundhog at 860y and rip a hole 2" across on the way out with a "sploosh" of blood that looked like you hit a pop bottle
 
Ballistics and Statistics are great to calculate and debate. Clinical (i.e. FIELD RESULTS) outcomes show a proper bullet in most common chamberings loaded to common speeds kill similarly, assuming a properly constructed game bullet goes thru vitals.
 
well the OP says 308, not 30cal class.

OP indeed says 308, which is the nominal diameter for 30cal class bullets.

Maybe the question should've been more specific - either cartridge or bullet weight; question itself is based on a false assumption that (quote) "6.5 mm or even 6.0 mm bullets have better ballistics coefficients and perform better at longer ranges".
 
Here is an interesting video on "terminal" effects. It's academic and medically related so expect it to be slow in some parts if you're short on the attention span side. The key take aways from this video however are the real world cases(people being shot, not just gelatin) and supposedly fatal shots on human targets that actually survived despite what would have been expected. The rifle ballistics part also covers some of the issues we were seeing overseas with regards to shooting bad guys and knock down power. The TCCC part is a bit outdated but given the time of filming, it was relevant then. Otherwise, enjoy the video.

[video=youtube;tku8YI68-JA]http://www.youtube.com/watch?v=tku8YI68-JA&sns=em[/video]
 
Last edited:
OP indeed says 308, which is the nominal diameter for 30cal class bullets.

Maybe the question should've been more specific - either cartridge or bullet weight; question itself is based on a false assumption that (quote) "6.5 mm or even 6.0 mm bullets have better ballistics coefficients and perform better at longer ranges".

MoBoost,

The fact that 6.0 mm and 6.5mm bullets have better ballistic coefficients is NOT an assumption or even a false assumption. For example, in this link regarding what the pro's use: http://www.snipershide.com/shooting...actical-shooters-equipment-what-pros-use.html you can see that EVERY one of them uses either a relative diameter of a 6.0 mm or a 6.5 mm bullet. NONE of them use a .308 diameter bullet. So clearly they know more than you do. There are no assumptions in my statement. If is simple fact. I would recommend that you review through the mountains of data available at JBM Ballistics, especially the Brian Litz models on the G7 drag models. When you compare the .308 to let's say the 6.0mm bullet profiles, the 6.0 mm bullets are VASTLY superior in wind drift, energy and drop.

Please provide the information I requested instead of just arguing your point and getting this thread off track.

Meanwhile, thank you to some of the other posters for giving me information regarding Pat Sinclair. I will reach out to him shortly. He certainly seems to have something to offer here.

ALSO, Kudo's to Papa Zero Three for the video. I watched that video last year and it is was VERY enlightening. I will watch it again but from what I remember, he mostly discussed the big difference between handgun and rifle calibers.
 
Common sense tells us that if we fling a 150-ish grain piece of lead at ~2500 FPS towards an animal's vitals, then said animal is highly unlikely to care much about a 1.12mm difference in projectile diameter.
 
I would recommend that you review through the mountains of data available at JBM Ballistics, especially the Brian Litz models on the G7 drag models. When you compare the .308 to let's say the 6.0mm bullet profiles, the 6.0 mm bullets are VASTLY superior in wind drift, energy and drop.

You are off your rocker, lets talk "information" - find me a 6/6.5mm with .350+ G7. Crack the book yourself, read the chapter on "speed vs BC": heavy slow high-BC will have less drift, more energy and longer danger zone down the range. 6/6.5s physically can't be "vastly superior" to 308s - unless you start coming up with undeclared clauses, scenarios and limitations.

The benefit of all the speed daemons is the flatness in short range scenarios = engaging unknown distance under 600 yards = what most of your tactical matches are all about. Short action, minimal recoil, flat shooting - perfect for that kind of scenario, but it doesn't change the physics of matter.

I am big fan of 6s myself - I have 7 rifles chambered in different variations. I am just not blind to the facts or eat up every new sales pitch.
 
Last edited:
30 cal will out perform 6.5 if we remove all physical limitations. The 240 gr 30 cal bullets will out penetrate a 140 gr 6.5 if both are moving out of the muzzle at 3100 fps. The question is, do you want carry that thing? Do you want feel that recoil? Are you willing to give yourself 7 stitches between your eyes to guarantee shot placement? Will you flinch? Ready for a quick follow up shot?

We do live in world with physical parameters. And some of them don't change with caliber choice:
You are only so heavy
You are only so strong
Your cheek weld is only so far away from your shoulder
Your scope is only going to be so far away from your eye
Your intended game will only be so big, tough, thick
Your game will only be so far away from you
There will be an equal and opposite recoil
Your powder is only going to burn so slow

There are also some generally recognized preferences with hunters. Most guys don't care for recoil beyond the level of a 30-06. Most guys don't want to carry a rifle over 10 lbs. Most guys don't want a barrel longer than 26". There is only so much powder that can be burned in 26". Most cartridges burn <70 gr of powder. Most game is <1000 yds away and <1000 lbs.

It seems like your asking about 6.5 vs .308 in a 308 Win sized case at ranges <600 yds. I will always choose a 6.5 there because I place more importance on penetration than would channel diameter. I always want two holes. The longer for caliber bullet will drill straighter, also. Straight penetration matters at least as much shot placement. Advantage 6.5. Speed kills, too. Roy Weatherby killed everything in Africa with a 257 Weatherby, hydrostatic shock matters. The only time I might choose a 308 or 30-06 is if I knew the shot would be <100 yds through brush and at a light skinned and framed animal <200 lbs. Even then it would be a coin flip. I don't have any links handy, but they shouldn't require too much google-fu to find.

If you live in the same physical universe that I do, and I'm sure that you do, then you will find the 6.5 is in a real sweet spot for hunting animals on this earth as it is today. I personally think it satisfies more physical requirements with less physical limitations than any bore size in the world. I personally think this mutual satisfaction of the needs of man and beast, coupled with the cartridges internal and external ballistics makes the 6.5 SAUM in an ~8 lb rifle, with a 24-26" tube the "best" hunting chambering in North America. YMMV. Different types of hunting will emphasize or nullify the importance of certain variables (you will have to use your own wisdom to decide your hierarchy of needs) and therefore lift-up or bring down cartridges and platforms. No cartridge is undefeated, but the 6.5 SAUM has a higher winning percentage than anything else I can think of.
 
I'll play - 308 Winchester case.
Try to beat wind drift and energy at 1000 yards of 215gn Hybrid (G7 .696) @ 2450fps MV.

What barrel length and load are you using to get a 215 to 2450fps from a 308?

In the interest of playing along:

500' ASL, 59F, 29.92"Hg, 0% RH at 1000 yards with 10mph crosswind

30cal 215 Hybrid @ 2450fps = 10.6mil drop (381.5), 1.9mil drift (70.10"), 928.6ft/lb energy
6.5mm 140 Hybrid @ 2900fps = 7.6mil drop (274.0"), 1.7mil drift (62.3"), 809ft/lb energy
6.5mm 140 Hybrid @ 2700fps (20" barrel) = 9.0mil drop (323.9") drop, 1.9 mil drift (69.6"), 668ft/lb energy

I don't think anybody would ever deny a substantially heavier, high BC 30cal bullet would have more energy at distance.
 
Last edited:
I own a 6.5x55 and a 308. My go to rifle for hunting is the 308 for one reason and that is ammunition availability. Having said that, I handload everyrhing but.... put yourself in the situation where you've flown in to a hunt and your sacred handloads get lost somehow. If it's a 6.5 round, you'd better borrow another rifle or stay at the lodge because finding a 6.5 round at the local Wallyworld or even the hardware store is zip, whereas, you can get 30 caliber (308) commercially manufactured rounds just about anywhere.

Thats not to say I don't pack both rifles in the Pelican but usually, I'll pack my 308 and my 338.

Ballistics are better in the 6.5 than the 308, I know that. 6.5 has a flatter downrange trajectory but I still prefer the 308.
 
30 cal will out perform 6.5 if we remove all physical limitations. The 240 gr 30 cal bullets will out penetrate a 140 gr 6.5 if both are moving out of the muzzle at 3100 fps. The question is, do you want carry that thing? Do you want feel that recoil? Are you willing to give yourself 7 stitches between your eyes to guarantee shot placement? Will you flinch? Ready for a quick follow up shot?

We do live in world with physical parameters. And some of them don't change with caliber choice:
You are only so heavy
You are only so strong
Your cheek weld is only so far away from your shoulder
Your scope is only going to be so far away from your eye
Your intended game will only be so big, tough, thick
Your game will only be so far away from you
There will be an equal and opposite recoil
Your powder is only going to burn so slow

There are also some generally recognized preferences with hunters. Most guys don't care for recoil beyond the level of a 30-06. Most guys don't want to carry a rifle over 10 lbs. Most guys don't want a barrel longer than 26". There is only so much powder that can be burned in 26". Most cartridges burn <70 gr of powder. Most game is <1000 yds away and <1000 lbs.

It seems like your asking about 6.5 vs .308 in a 308 Win sized case at ranges <600 yds. I will always choose a 6.5 there because I place more importance on penetration than would channel diameter. I always want two holes. The longer for caliber bullet will drill straighter, also. Straight penetration matters at least as much shot placement. Advantage 6.5. Speed kills, too. Roy Weatherby killed everything in Africa with a 257 Weatherby, hydrostatic shock matters. The only time I might choose a 308 or 30-06 is if I knew the shot would be <100 yds through brush and at a light skinned and framed animal <200 lbs. Even then it would be a coin flip. I don't have any links handy, but they shouldn't require too much google-fu to find.

If you live in the same physical universe that I do, and I'm sure that you do, then you will find the 6.5 is in a real sweet spot for hunting animals on this earth as it is today. I personally think it satisfies more physical requirements with less physical limitations than any bore size in the world. I personally think this mutual satisfaction of the needs of man and beast, coupled with the cartridges internal and external ballistics makes the 6.5 SAUM in an ~8 lb rifle, with a 24-26" tube the "best" hunting chambering in North America. YMMV. Different types of hunting will emphasize or nullify the importance of certain variables (you will have to use your own wisdom to decide your hierarchy of needs) and therefore lift-up or bring down cartridges and platforms. No cartridge is undefeated, but the 6.5 SAUM has a higher winning percentage than anything else I can think of.

NOW THAT IS WHAT I'M TALKING ABOUT.

This is a well thought out and reasoned post. Thank you jakelly. Information > arguments. I just wish there was actual ballistics gelatin information to prove your discussion. Nonetheless, this post gives a lot of food for thought.

Okay guys, keep em coming. I would like to hear from the "sniper" community, if possible. I am hearing a lot from hunters, which is VERY valuable information. But I would like to know if there is experience on the other end of the spectrum. I am just so curious that since the 6.5mm cartridges have been around (such as the 6.5x57) for so long, why didn't our U.S. military go with that as a sniper round over the .308 Winchester or the 300 Winchester Magnum?
 
NevadaZielmeister said:
I am just so curious that since the 6.5mm cartridges have been around (such as the 6.5x57) for so long, why didn't our U.S. military go with that as a sniper round over the .308 Winchester or the 300 Winchester Magnum?

Because institutional momentum and supply chain logistics.

See: 1903, M1 Garand, creation of 7.62x51, etc etc etc.
 
What barrel length and load are you using to get a 215 to 2450fps from a 308?

In the interest of playing along:

500' ASL, 59F, 29.92"Hg, 0% RH at 1000 yards with 10mph crosswind

30cal 215 Hybrid @ 2450fps = 10.6mil drop (381.5), 1.9mil drift (70.10"), 928.6ft/lb energy
6.5mm 140 Hybrid @ 2900fps = 7.6mil drop (274.0"), 1.7mil drift (62.3"), 809ft/lb energy
6.5mm 140 Hybrid @ 2700fps (20" barrel) = 9.0mil drop (323.9") drop, 1.9 mil drift (69.6"), 668ft/lb energy

I don't think anybody would ever deny a substantially heavier, high BC 30cal bullet would have more energy at distance.

Damn, went for the heavies, didn't you!? Ok, you win, 308 just doesn't have the case capacity to push 308 heavies (230s).
 
This is some interesting stuff. Either way, if you send a a high speed chunk of metal through the vital organs, something is going to die. I'll bet on shot placement every time.

This.

I've taken deer from 80 yards to 700 yards with a 308, using 180 smk @ ~2550fps.

None expanded, all penciled right through (the vitals).

All deer ran between 10 and 50 yards.

All were dead.
 
I would agree, if 6.5 SAUM was available in said North America, or if brass was easily available, or even if bolt face in short action was more common ....

From logistics point of view I'd take 308-based 6.5s.
Give George and Pat a couple months and I bet that brass issue is solved. Give them a couple years they might just have a factory chambering. In terms of available actions, well, I only need one. I have never put much stock in replacement ammo, because I just don't like the odds of that happening, and if it does I don't see how a guy is that much further ahead with ammo he doesn't know, even if it safely chambers and fires. I'll could have Copper Creek send me some overnight, I guess.

I do agree though, that these are currently the chief limitations of this cartridge, and that the 6.5 cartridges using a .473 boltface have a leg up there, but for me those don't tip the scale back from 200 fps in increased velocity with longer barrel life.
 
Would anybody consider a 308 good enough for Alaskan Grizzly?

30-06?

300WM?


To be 100% truthful I don't think there is any living animal on the face of the earth that you could not stop with a 308.

I've shot a shit ton of feral cattle, buff, donkeys, horses, pigs ect with the round. Loaded with ADI fmj or win 180gr powerpoint and the good old silver tips.

But then again I've also shot buff with a Rem 788 chambered in 222.
 
Check out the development of the British EM-2 Bullpup Rifle in the 1950s which was originally based on a .280 cartridge.

EM-2 rifle - Wikipedia, the free encyclopedia

http://www.forgottenweapons.com/rifles/british-em-2/

You can thank the lovely NATO 7.62 and the pressure from the US for killing that one.

Per those studies, the 7mm bullet was determined to be optimal for both external and terminal ballistics for "typical combat conditions", and coming out of the .280 had manageable recoil and good barrel life.

Amazing that someone figured that out over 60 years ago, yet the argument is still going on today.

Per below, 7mm bullet out of a magnum dropping an Elk at 1376 yds.
http://m.youtube.com/watch?v=eIn1G8BeUuc
Anyone want to try that with a .243, 260, or .308?

Per my original post, all of the variables have to be considered to determine what will or will not work for a given application.
 
Last edited:
What barrel length and load are you using to get a 215 to 2450fps from a 308?

In the interest of playing along:

500' ASL, 59F, 29.92"Hg, 0% RH at 1000 yards with 10mph crosswind

30cal 215 Hybrid @ 2450fps = 10.6mil drop (381.5), 1.9mil drift (70.10"), 928.6ft/lb energy
6.5mm 140 Hybrid @ 2900fps = 7.6mil drop (274.0"), 1.7mil drift (62.3"), 809ft/lb energy
6.5mm 140 Hybrid @ 2700fps (20" barrel) = 9.0mil drop (323.9") drop, 1.9 mil drift (69.6"), 668ft/lb energy

I don't think anybody would ever deny a substantially heavier, high BC 30cal bullet would have more energy at distance.

I'm thinking a 30-06 with 20-22" barrel shooting 215gr hybrids @ 2450 would be a sweet do it all huntin rifle!!
 
Per those studies, the 7mm bullet was determined to be optimal for both external and terminal ballistics for "typical combat conditions", and coming out of the .280 had manageable recoil and good barrel life.

Amazing that someone figured that out over 60 years ago, yet the argument is still going on today.

60 years? Try double that ... Mr. Mauser got it right the first time.
 
LR101, shooting elk at that distance with anything is a stunt for ego pump. It is unethical. They have been shot dead at 900 yds with a 243, no diff.

If I can't get within 600, hell really 400 yds, I need to work on my hunting skills. HUNTING is called HUNTing while Sniping is just that, it makes no diff if you wound an enemy, and it might have a desired effect. On Game, I will not take stupid shots. I would never allow or condone my sons or anyone attempting such stunts. Doable, possible, sure, but when you look at all the variables and the risk of things going wrong, such shooting at game is unethical, period.

Back to the debate, when one is choosing x over y, the end goal must be identified. Chewing ballistics is mental masturbation. If we are looking at effectiveness on the battlefield, or in the game fields, decide first the end goal. In some, a mere 6mm bore with high BC bullets might trump the larger bores, less recoil, flatter, less drift, and deadly results. It all depends.....but what ballistic calculators leave out, is bullet construction, impact velocity, rotational fps (think keeping nose fwd w/min yaw for max penetration), shot angle/placement on a specific shot, to a specific target.
 
LR101, shooting elk at that distance with anything is a stunt for ego pump. It is unethical. They have been shot dead at 900 yds with a 243, no diff.

If I can't get within 600, hell really 400 yds, I need to work on my hunting skills. HUNTING is called HUNTing while Sniping is just that, it makes no diff if you wound an enemy, and it might have a desired effect. On Game, I will not take stupid shots. I would never allow or condone my sons or anyone attempting such stunts. Doable, possible, sure, but when you look at all the variables and the risk of things going wrong, such shooting at game is unethical, period.

Back to the debate, when one is choosing x over y, the end goal must be identified. Chewing ballistics is mental masturbation. If we are looking at effectiveness on the battlefield, or in the game fields, decide first the end goal. In some, a mere 6mm bore with high BC bullets might trump the larger bores, less recoil, flatter, less drift, and deadly results. It all depends.....but what ballistic calculators leave out, is bullet construction, impact velocity, rotational fps (think keeping nose fwd w/min yaw for max penetration), shot angle/placement on a specific shot, to a specific target.

While I agree it's HIGHLY UNETHICAL to take shots at long range if YOUR NOT SURE ABOUT YOUR ABILITIES TO MAKE THE SHOT... I never hear respected Hide Member PSinclair getting dogged on for shooting Antelope at 1200 plus yards.
Hell, I shot a doe Saturday with a 230 OTM at 656 yards. She dropped dead right there. Only reason I took the shot is because I knew my #'s and drops at that distance. I wouldn't recommend it to ANYBODY to shoot at that range but I know my numbers and I know MY abilities.