6.5 Grendel versus 6mm ARC for whitetail

[JASmith]

I love my Grendels. if I lived and hunted elk as a resident not paying for out of state license very with limited hunting time I would use the Grendel for elk without a doubt. It would be the CZ527 I had converted to Grendel before there were any bolt actions available in this great little round. I put it together as a light weight boltaction hunting rifle that is accurate and only weighs 7.2 lbs ready to hunt with, scoped, loaded and sling. Much more pleasurable to carry when hunting especially in the mountains than my heavier larger caliber rifles. I started with a 24 inch barreled AR and like what it does on game and target but just prefer bolt actions for deer hunting.

Hunting out of state on expensive hunts with limited time I carried larger longer range rifles such as 7mmSTW, 300 Weatherby to name a couple one trip the STW scope died so I used my backup 350 Remington Mag which worked great.

Well said!

The strongest and most successful advocacy (sales pitch) results from knowing where a cartridge fits and when others might be more useful in SPECIFIC situations.

It is also a very fine general purpose round in bolts and single shots. We have all three.

That said, the Grendel is the most flexible cartridge compatible with the AR available today.

[chatterbox]

It took awhile, but I finally ran the .243 through the age old formules and here is the same chart with the results: (Note the correction on the 6mm ARC, it was misplotted.)

Outside of the range of 200 yards to 210 yards, where it is either going too fast (meat destruction) or lacks penetrating power (>1300 ft/sec for elk), the .243 is a P.O.S. cartridge and caliber. This is nothing new. I was told that as an adolescent in the 1960's. This chart is just a metaphor for what has been known all along, the 6mm (.243) is not a caliber to be hunting big game with. What was Hornaday thinking when they brought the 6mm ARC out as the panacea for all hunting needs? What are our sporting good suppliers thinking when they dropped the Grendel for the ARC?

If this mindless, erroneous propaganda continues, and it well, the 6.5 Grendel will soon be dead. This winter we have travelled 5,000+ miles, visited 5 gun shows and 20+ gun stores. During that time I bought every grendel that I encountered, a total of three, and one of these was from Gun Brokers. This is commercial warfare, and your forum is the front lines.[ATTACH=CONFIG]19475[/ATTACH]

[Stinky Coyote]

It took awhile, but I finally ran the .243 through the age old formules and here is the same chart with the results: (Note the correction on the 6mm ARC, it was misplotted.)

Outside of the range of 200 yards to 210 yards, where it is either going too fast (meat destruction) or lacks penetrating power (>1300 ft/sec for elk), the .243 is a P.O.S. cartridge and caliber. This is nothing new. I was told that as an adolescent in the 1960's. This chart is just a metaphor for what has been known all along, the 6mm (.243) is not a caliber to be hunting big game with. What was Hornaday thinking when they brought the 6mm ARC out as the panacea for all hunting needs? What are our sporting good suppliers thinking when they dropped the Grendel for the ARC?

If this mindless, erroneous propaganda continues, and it well, the 6.5 Grendel will soon be dead. This winter we have travelled 5,000+ miles, visited 5 gun shows and 20+ gun stores. During that time I bought every grendel that I encountered, a total of three, and one of these was from Gun Brokers. This is commercial warfare, and your forum is the front lines.[ATTACH=CONFIG]19475[/ATTACH]

grendel will survive, so will the arc, these are proper 21st century cartridges, they are just getting warmed up, like the 6.5 creedmoor over the 6....the 6.5 will always get the nod for hunting and the 6 will always get the nod for steel work, funny the 6.5 came first in this so it was a slower start, the arc will help pull it along as there's far more steel/competitive 6mm guys that love the short fats than hunters so the arc (I mean 6mm Grendel ) is a good thing, also, terminal ballistics still largely misunderstood, the best formula to go by at this point is starting sd, construction type, and impact velocity....FOR GAME INTENDED

the best example of why ft/lbs is useless is bell and his 6.5 mannlicher (on elephants) vs the 700 nitro express, the 6.5 mannlicher has higher sd solids launched at higher velocities (I think 156-160 gr, .32 sd at ~2350 fps) and the 700 nitro throwing 1000 gr, .29 sd, at 2000 fps....you've got less than 2000 ft/lbs with one and about 9000 ft/lbs with the other but the mannlicher is more reliable into the brain pan through a foot of elephant skull, and the 700 nitro has been knocking elephants out and they come to and rodeo begins....the sd doesn't change on these solids but it clearly shows that .29 sd at only 2000 fps is not enough penetration regardless the energy behind it, but bell learned long ago that .32 sd launched over 2300 fps is enough

now you look at our game and bullets, we use rapidly changing sd bullets, we currently don't measure the rates of this change to compare, I'm sure we will at some point in this century, but the point is then that we have to visualize that we must start with an adequate amount of sd for game intended and a construction type and velocity range to make the bullet work for game intended, ie; you can have a good starting sd but if construction is too fragile for the velocity range you will have violent damage over too short a distance in the animal (taking only a shoulder perhaps) but the same bullet slowed down can then do the work required over a longer distance....so the Weatherby barnes is an example of one end of spectrum, with bullets retaining what sad sd they start with but driven at wicked speed to make them work better, inefficient especially at the shooters shoulder, but you can take a rapid construction (heavy for cal) type bullet at moderate velocities and have very efficient performance, enter the 6.5's as they have unusually high sd for caliber bullets across the range, so you can do more with a lot less powder burned

anyway, energy is a useless number, I figure it will be used properly at some point once we have sdrr (sectional density reduction rate - a term I coined in 2020) and err (energy reduction rate - also coined in 2020) and it will work like this, we can measure a finished bullets sd over a distance in gel perhaps, then use the impact energy and divide it over the inches travelled to give the err, which would then help explain to folks the likely damage they may see internally over that distance as compared to another cartridge/bullet example, you may have a creedmoor dumping 70 ft/lbs per inch over 22" and a 300 wm dumping 130 ft/lbs per inch over 26"....just random examples, back to the sdrr...it would be a measure of penetration depth it will achieve, so you'd have both measures (penetration and energy) in more objective format!, I feel like this will be coming this century, it must, because the amount of cyberspace eaten up discussing the still subjective subject is proof we have a long ways to go, inflight ballistics we've got down pat to 21st century levels of understanding...not much work left to do there, but terminal ballistics we're still stuck in the 20th century

and a 6 arc with 108's will shine from 200-600 yards no prob, it's got great sd, but agree it's a bit fast on the front end for that bullet so will want to keep it in the ribs on bigger animals, the grendel speeds from muzzle to 4-500 yards is absolutely perfect for 123gr eld/sst bullets construction type, maximum efficient imo, keeping impacts between 2350-1750 fps, no elk/moose will take the 123 well in the ribs at 400 yards, you will get your 20" penetration and necessary damage through that travel, the barnes are too tough for these cartridges imo, really limit their range as they need at least 2000 fps to open up just a tiny bit, you will kill with the barnes but I believe more poked holes and longer follow ups whereas you'll walk right up to your game a lot more frequently with the eld/sst bullets

[LRRPF52]

It took awhile, but I finally ran the .243 through the age old formules and here is the same chart with the results: (Note the correction on the 6mm ARC, it was misplotted.)

Outside of the range of 200 yards to 210 yards, where it is either going too fast (meat destruction) or lacks penetrating power (>1300 ft/sec for elk), the .243 is a P.O.S. cartridge and caliber. This is nothing new. I was told that as an adolescent in the 1960's. This chart is just a metaphor for what has been known all along, the 6mm (.243) is not a caliber to be hunting big game with. What was Hornaday thinking when they brought the 6mm ARC out as the panacea for all hunting needs? What are our sporting good suppliers thinking when they dropped the Grendel for the ARC?

If this mindless, erroneous propaganda continues, and it well, the 6.5 Grendel will soon be dead. This winter we have travelled 5,000+ miles, visited 5 gun shows and 20+ gun stores. During that time I bought every grendel that I encountered, a total of three, and one of these was from Gun Brokers. This is commercial warfare, and your forum is the front lines.[ATTACH=CONFIG]19475[/ATTACH]

Hornady did 6mm ARC for a specific military unit looking to replace their SR-25s, because they were experiencing all the problems with 7.62 NATO weight, bulk, recoil, both in and out of the house.

They did a series of practical application tests with 12-18” barrel 6.5 Grendel AR-15s in different positions, shooting scenarios, and recreations of operational problems they encountered overseas.

Each shooter was asked if there were any scenarios where they would have preferred 7.62 NATO instead, and without exception, each said “no”, the 6.5 Grendel was preferred in each scenario.

Hornady then said they could tweak it to make it better, and necked it down to 6mm.

6mm Grendel has been a thing in AR-15s for Hi-Power since Grendel brass was available, so nothing new.

Having spotted and RO’d at long range matches and training events since 1996, I personally like to see and hear the impact of more projectile mass on-target.

The 6mms are flatter and have less recoil, but are hard to hear or see impact steel sometimes, especially as you get out farther.

6.5 Grendel even from my 12” is very audible on steel.

From 16” and longer, it hits the steel pretty hard at distance.

6mm is great for varmints and coyotes, adequate for deer-sized game within certain ranges, but there’s an argument for the projectile mass and bullet selection for 6.5mm on medium game that is hard to argue with.

I have seen people take elk with 6mm Dasher, 6mm Creedmoor, and 6mm BR, but they were competitive shooters used to putting rounds on small targets regularly, and made excellent heart/lung shots on their elk.

6.5 Grendel is the external ballistics equivalent of the 6.5x54 Mannlicher and 6.5x52 Carcano. MVs from those compared with Grendel from the same barrel lengths overlap nicely.

Grendel just does it from a 39mm length case and without pushing pressure much higher, which is impressive in its own right.

[chatterbox]

The saga continues. Spurred on by talk of the 6mm Creedmoor, I ran it through the formulas, and the results are in the reattached chart. Nuff said.[ATTACH=CONFIG]19477[/ATTACH]

[chatterbox]

Of course these charts are for the use of the AR-15 for elk. If there is an interest, I could run the same chart for deer sized game. The difference being the requirement of 1300 ft/lb for penetration on elk vs. 1000 ft/lb for penetration on deer.

[Stinky Coyote]

Again, we’re well past 20th century subjective speak on terminal ballistics, ft/lbs energy is useless measure, don’t believe me? Start here to get up to speed the fastest. 2019 start, 147 pages deep, you’re welcome. https://rokslide.com/forums/threads/223-...se.130488/

[stonehog]

Bravo, Chad! Best chart I’ve seen in a long time! Very interested in this for deer.

[LRRPF52]

Again, we’re well past 20th century subjective speak on terminal ballistics, ft/lbs energy is useless measure, don’t believe me? Start here to get up to speed the fastest. 2019 start, 147 pages deep, you’re welcome. https://rokslide.com/forums/threads/223-...se.130488/

I’ve read through a lot of that thread. Most of it is opinions and talk without posts of actual animals killed, though there are some about every 3 pages, mostly deer, coyotes, antelope, and some cats.

The OP has shot some elk within 100-260 yards with the 77gr TMK from a bolt gun, broadside shots through the heart/lungs.

Nothing really surprising there.

A great thread with only posts of animals taken, what bullet, barrel length, shot distance, and distance traveled after the shot can be found here:

Grendel knock-down survey

For elk hunting in the Mountain West Region of the US, we see a lot of longer distance shot opportunities, even with stalking into within 300-400yds.

They aren’t like hunting in thick brush out East looking for deer.

[JASmith]

To repeat and emphasize earlier posts about the futility of advocating kinetic energy as a metric for hunting potential:

Broadhead arrows generally have less than 100 ft-lb of energy at the bow. Yet, hunting arrows frequently pass clear through their quarry.

The lethal mechanism is the cutting and slicing of blood vessels and vital organs.

So, anyone who touts a kinimum kinetic energy for hunting on any but state hunting law minimums, is not a credible advocate for hunting cartridges and bullets.

[Stinky Coyote]

I'm kind of surprised to find this discussion happening on a 6.5 Grendel forum, a case that burns 30 grains of powder, those who gravitate to cartridges like this generally have a far deeper understanding of terminal ballistics. Anyway, everyone can have a good read, understand Kilimanjaro Bell killed some ~1100 elephants with pretty moderate velocity 6.5 and 7mm with extra high sd bullets for a good bunch of them and Craig Boddington himself I believe is penned in article about the 700 nitro express only knocking out elephants at times, lacking a couple key measures...one of them is not ft/lbs. The guys on rokslide killing elk to 400 yards and a bunch of other big game recording since 2019 is a very eye opening thread to corroborate with .223's and 77gr tmk's the very thing I'm talking about...energy is a useless measure in terminal ballistics at the moment. There's moose in there, piles of deer, bears, elk, and it takes a holiday break to get through it all. Many people posting just can't believe I guess, then guys that actually do the killing post and the evidence is all there. You match appropriate sd, construction, and impact velocity for game intended and there's magic. Just winging it on headstamps and horsepower is so 20th century. All the info is available to date to understand it this far. We will take it further soon enough. What's that law about the 1 in 100 monkey's? lol, eventually more will realize there is info we are missing that could make this far more objective. Finished SD and penetration depth, showing expansion ratio, showing energy dump per inch. If that is made comparable across the board one can see why the old favourite combo's worked as well as they did and also help choose future options and also explain it all. Right now I'm the 1 monkey, it's gonna take a minute.

[JASmith]

+1 Stinky!

[LRRPF52]

I'm kind of surprised to find this discussion happening on a 6.5 Grendel forum, a case that burns 30 grains of powder, those who gravitate to cartridges like this generally have a far deeper understanding of terminal ballistics. Anyway, everyone can have a good read, understand Kilimanjaro Bell killed some ~1100 elephants with pretty moderate velocity 6.5 and 7mm with extra high sd bullets for a good bunch of them and Craig Boddington himself I believe is penned in article about the 700 nitro express only knocking out elephants at times, lacking a couple key measures...one of them is not ft/lbs. The guys on rokslide killing elk to 400 yards and a bunch of other big game recording since 2019 is a very eye opening thread to corroborate with .223's and 77gr tmk's the very thing I'm talking about...energy is a useless measure in terminal ballistics at the moment. There's moose in there, piles of deer, bears, elk, and it takes a holiday break to get through it all. Many people posting just can't believe I guess, then guys that actually do the killing post and the evidence is all there. You match appropriate sd, construction, and impact velocity for game intended and there's magic. Just winging it on headstamps and horsepower is so 20th century. All the info is available to date to understand it this far. We will take it further soon enough. What's that law about the 1 in 100 monkey's? lol, eventually more will realize there is info we are missing that could make this far more objective. Finished SD and penetration depth, showing expansion ratio, showing energy dump per inch. If that is made comparable across the board one can see why the old favourite combo's worked as well as they did and also help choose future options and also explain it all. Right now I'm the 1 monkey, it's gonna take a minute.

What I’m saying is that they need to have a thread with only actual field results on game, rather than .30 caliber arguing that something smaller isn’t valid. Just let the field results do the talking, with all metrics posted.

I ran into some guys back in the 2000s who used a combo of .223 Rem AR-15s and .243 WSSM AR-15s to do depredation and other elk hunts here in Utah. With the .223 Rem, they said they always kept it within 200yds and did head shots, and used the .243 WSSM for farther distances with normal vital zone, if I recall the conversation correctly. Fudds commonly told them they can’t do that because of "muh thirty-ought-six", and yet they had a large body count and far more experience actually putting animals down.

[Stinky Coyote]

What I’m saying is that they need to have a thread with only actual field results on game, rather than .30 caliber arguing that something smaller isn’t valid. Just let the field results do the talking, with all metrics posted.

I ran into some guys back in the 2000s who used a combo of .223 Rem AR-15s and .243 WSSM AR-15s to do depredation and other elk hunts here in Utah. With the .223 Rem, they said they always kept it within 200yds and did head shots, and used the .243 WSSM for farther distances with normal vital zone, if I recall the conversation correctly. Fudds commonly told them they can’t do that because of "muh thirty-ought-six", and yet they had a large body count and far more experience actually putting animals down.

I agree, but what's unique about the thread is that it was allowed to run free from inception. Most topics like this that get started anywhere else tend to get locked, deleted, and or lost to the web forever. So people with actual experience doing it within that thread got to routinely drive the point home. Yes, that means it has a lot of noise you don't want to read but take it for what it is...un unmoderated thread that started 4 years ago of what many would consider the ultimate expression of understanding terminal ballistics in this day and age. You won't find one anywhere else so kudos to rokslide and holding to the 1st amendment for allowing that to remain. It's a great resource imo and here is an ideal thread to reference it. It definitely lends a little comfort to those of us shooting Grendel's or Arc's lol. We're a little over headstamped compared to that thread lol, we're burning more powder with much higher sd's and larger diameter and heavier bullets. And many would consider the Grendel at the minimum threshold. Funny though, 98% of big game shot within that say 300 yard threshold, a very 'non-fat' option but it's certainly not a minimal edge as many seem to think from their 20th century tinted glasses.

[LRRPF52]

One of the driving factors for Bill Alexander choosing the 6.5mm was the wide projectile selection that already existed for both hunting and target purposes.

Most of the hunting bullets were designed for moderate velocity cartridges, which meant they would work perfectly at Grendel velocities on white tail and hogs.

Offer a cartridge that fits in the AR-15 that facilitates cleanly taking medium game, and it will attract a lot more sales and market acceptance.

If you lived through the 6.8 SPC saga, they had to develop most of the hunting bullets for it after the fact, since the only common cartridges in .277” were the .270 Winchester and .270 Weatherb.

Since those both produce exceptionally-high velocities shooting mid-weight bullets in the 130-150gr class, only the varmint bullet weights were usable in the 6.8 SPC.

From an industrial scaling standpoint, it was an uphill battle to get a decent spread of appropriate bullets to market for the limited ogive lengths mandated by the 6.8’s longer case length, and AR-15 limited COL.

Grendel with the short, fat case had all kinds of available ogive length, which meant pretty much any 6.5mm bullet could be loaded, even the 144gr Lapua FMJ and the 160gr Hornady RN, as well as the Sierra 85gr Vermonter, 90gr Speer TNT, 95gr V-MAX, all the 100gr 6.5mm, and of course the 120-130gr bullets. If you wanted higher velocity explosive performance with 16” of penetration, you could load the 100gr ELD-M or 100gr NBT from 22-24” and keep them limited to broadside shots with perfect heart/lung intersection. If you want more aspect options, the monoliths and bonded bullets make more sense, but don’t open up as much of a wound cavity like cup/core do. Maker Trex is a good in-between with really large petal expansion.

6mm is also versatile, but of course leans on the lighter weight class projectiles ideal for varmint and close-in medium game. You could shoot the 90gr ELD-X really fast, or 80gr GMX.

.25-06 has been used to reliably kill elk for ages, normally within that 300-400yd range. Same with mule deer out farther.

To me, .25-06 isn’t an efficient cartridge, but the performance is there. The case is way too long for what it’s doing, and could be achieved with a shorter case that’s designed better.

25 WSSM, 25x47 Lapua, .257 Roberts AI, or 25 Creedmoor Imp 40, etc.

For white tail, pretty much any centerfire rifle will do the trick within reasonable range for the cartridge.

[Stinky Coyote]

Well played Bill, and that other guy.

In Canada AR's aren't really a thing, so as an avid ballistics nerd and hunter looking to find max efficiency and no fat for my goals it just happened to start with that 123gr bullet then figuring out what case would drive it with the same no fat goals...the Grendel may not have been designed for hunting but this ballistics nerd/hunter was drawn to it right from the get go. I don't reload so had to wait a long time to get my hands on it this side of border, but have run it exclusively for 5 seasons now and batting 1000. Moose, black bear(3), sheep, whitetails, muley, and a wolf. 10-420 yards, average shot distance 163, average recovery distance 13 yards, 15 animals, walked right up to everything afterwards. In the 30 grains of powder class, and extra short action class....it's as efficient as one can get for a hunting focused off the shelf buyer.

[Fess]

Effectiveness of hunting cartridges depend a lot on how an individual bullet behaves in game. At one time I analyzed several of the "killing power" formulas and they all seemed designed to prove the biases of their authors. Some favored initial bullet diameter, others bullet weight, some velocity and many favored sectional density of undeformed bullets. None that I have seen do a decent job of compensating for different bullet types.

For a long time, sectional density (weight divided by diameter squared) was considered by many to be one of the most pertinent measurements for medium and big game "killing power". It is still useful when working with non-expanding, non-fragmenting round and flat nosed bullets. What really happens inside game with other types of bullets, though, is that the the "effective SD" changes from expansion (increased effective diameter) or core (weight) loss. Bullets that maintain their weight (many bonded and monolithic) tend to penetrate much deeper with a lower initial SD than traditional cup and core bullets. Bullets that maintain a large expanded diameter may penetrate less than expected from "parachute effect".

Partition and similar bullets limit weight loss and maximum expansion by assuring that the base stays intact and cannot expand. Whole other classes of bullets depend upon full or partial fragmentation to damage tissue around the wound track. In short, most "killing power" formulas have very limited usefulness and are no longer viewed as being useful by bullet and ammo manufacturers except when limited to specific examples.

The most entertaining recent example is with the "Hornady Index of Terminal Standards" which was once very prominent on Hornady's website. The H.I.T.S. formula depends upon the weight of the bullet, squared, multiplied by velocity and divided by diameter, squared. It was developed around Hornady's cup and core bullets, but it turned out to be a terrible predictor for their own monolithic bullet performance in game. Copper alloy monolithic bullets are less dense and thus lighter weight than similarly shaped lead core bullets. The weight, squared component dramatically dropped their H.I.T.S score. Hornady's monolithic bullets retain virtually all their original weight, though, so their higher effective SD produces deeper penetration than Hornady's own expanding lead-core bullets, which typically lose some core weight. Although few seemed to notice, Hornady stopped using the H.I.T.S formula soon after it started producing its monolithic GMX bullets. I suspect it was largely because their own formula underestimated the real-world bullet performance of their own new bullets!

[LRRPF52]

Excellent observation and points Fess.

In conversations with Hornady, they said one of the things they noticed is rotational energy and its relationship with expansion when they started doing ballistics gel tests at 400yds.

I think it’s also becoming clear to many that too much velocity for a certain bullet construction is not a good thing. There’s a happy window of expansion and penetration that produces more predictable wounding effects.

The bullet makers knew this already generations ago, when the .270 Winchester and .270 Weatherby Magnum (any of the Weatherby’s) became more popular.

That’s literally why Nosler made the Partition, because legacy cup and core bullets were lead-showering into the meat upon impact, which caused traumatic avulsion and superficial depth tissue damage, but varying degrees of penetration that weren’t predictable.

The Nosler Partition wasn’t the ultimate mouse trap though, since high supersonic impacts would not only fragment the nose, but blow the rear core out the back.

Barnes jumped on board after that with a whole different approach to bullets with the original X in 1989, then later the TSX in 2003, the TTSX in 2007, VOR-TX in 2010, LRX in 2011, etc.

Nosler introduced the Accubond in 2003, where the jacket and core would be bonded together in a proprietary process to prevent total fragmentation and separation of the lead core and jacket from each other, while still facilitating controlled expansion at a designed impact velocity spectrum that tended to favor the higher velocities common in a lot of larger case volume rifle cartridges.

Hornady also introduced the Interbond in 2003, with a different approach to the jacket and bonding process.

Swift introduced the Scirocco in 1999 with a pure lead core and pure copper jacket for elasticity, eliminating zinc. The Scirocco II was introduced in 2006, and the 130gr was actually a factory load from Alexander Arms.

Bullet manufacturers have the tough job of developing and testing hunting bullets that will penetrate and expand across a wide range of impact speeds, from a wide variety of rifle cartridges that have significantly different muzzle velocities.

Factors we have accounted for with modern understandings of applied terminal ballistics include:

1. Impact velocity
2. Construction
3. Rotational speed (tighter twist rate = higher RPMs)
4. Expansion behavior across the impact velocity spectrum
5. Retained core/tail weight after initial expansion/nose material loss or deformation
6. Optimum employment envelope

Once we take all that into account, we can determine an optimum employment zone for any firearm/hunting bullet combination.

Any firearm/bullet combo will kill reliably within a certain range.

The beauty of 6.5 Grendel is that it will do it within normal hunting distances without needing premium bullets, with very low recoil and muzzle blast, from anything ranging from an AR-15 pistol to a longer barrel rifle.

There is a benefit from the premium long range hunting bullets like the 129gr ABLR, because they work exceptionally well from short barreled 6.5 Grendels within common distances.

Unlike most rifle/cartridge combos used for hunting, you can shoot all day with 6.5 Grendel and not be fatigued, and not torch your rifle’s chamber.

[Double Naught Spy]

So, anyone who touts a kinimum kinetic energy for hunting on any but state hunting law minimums, is not a credible advocate for hunting cartridges and bullets.

I have a couple of viewers that seem to think kinetic energy is the be all to end all of hunting/killing data, regardless of how many times I explain why I don't bother with it, LOL. I provide enough information that they could easily compute it, but that isn't good enough.

Effectiveness of hunting cartridges depend a lot on how an individual bullet behaves in game. At one time I analyzed several of the "killing power" formulas and they all seemed designed to prove the biases of their authors.

I am starting with your 2nd sentence. From the formulas I have looked at, I would say that they were designed to support the perspectives of the writers. Sure, they were biases, but every opinion we have is biased, right? I am not sure writing a formula that derives a number you deep useful for making a selection is necessarily a "bias" issue. The attempts may not have covered everything, but they covered what the particular authors thought was best to explain caliber/bullet/ammo/load choices.

How the bullets behave in the game is HUGE, in my (biased) opinion. I don't think we could put a formula to it, not a single formula, anyways.

The problem with the notion of how bullets perform in game is that it is HUGELY VAGUE. In part, this is due to all of the shooter introduced variables (e.g., shot placement, anatomy knowledge, etc.), bullet induced (e.g., ballistics, how consistently does the bullet perform in a given medium, after hitting bones of different sizes, shapes, densities, etc., and animal/biology induced, and animal induced (e.g., construction and makeup of the animal). Never mind that different types of bullets will perform differently by design and folks will summarily discount certain types of bullets that don't perform in a manner that they like even if they are equally lethal or more lethal.

It is probably just about impossible to come up with a mathematical predictive model/formula that will tell you about lethality across the board, but what said authors were trying to do was to help replace some of the willy nilly logic and biases of hunters based a bit on experience, a bit on the amazing picture on the box, based on what their father/brother/uncle/best buddy shoots, based on what they read in a magazine (those guys are all unbiased experts who write solely for the benefit of sharing their knowledge, right?), etc.

I get a lot of advice from folks on what bullets (and calibers) I should be using. From what I have learned, whatever I am using is wrong based on somebody else's opinion. My favorite are the folks that are trying to help me by telling me what works for them. Mind you, I am hunting hogs and I get notes like, "You really should try X. I killed two deer with it last year and they were DRT, though I had to track one about 60 yards."

This is a pretty stupid endorsement. A sample of 2 is pretty much worthless, though the sample is positive, which is nice. Never mind that they are talking about a different animal and different types of hunting. Never mind that they don't understand that DRT means that the animal dies where shot, not after running 60 yards. However, is this endorsement any better or worse than a Taylor KO value? I don't think it is any better, but I don't think it is any worse. It just doesn't sound as mathematical or scientific.

JASmith mentioned that he didn't know when folks got fascinated with kinetic energy values. I don't know either. It seems velocity and energy are tied up in all the calculations, so they must the pretty important. However, energy seems to be the most simplistic universal concept that even the most ignorant of people can figure out how to calculate and wouldn't it be nice if we just assumed that more is better and now we have a super simple system, only it doesn't work.

Some of my viewers have told me (a couple have told me repeatedly) that I need to be using a caliber that generates more energy. So I ask these folks what energy will do. They tell me that it kills the animal. I ask how it kills the animal and they can't tell me. They will start to talk about hydraulic shock or hydrostatic shock (often because they don't know the difference between the two) but can't tell me what is necessary for said shock to occur, but it involves energy. So where I am going with this is that folks get a concept stuck in their heads like a brain worm that superficially seems to make sense, seems to work, and that they can calculate and BOOM, they have their answer, even if it isn't based on fully useful concepts.

[Stinky Coyote]

Yup, it's a wildly subjective mess. Good post. Ran into a guy on rokslide that's considered a top authority there and he's pretty well versed in all the 'temp wound cavity, permanent wound cavity, stretch study results' and whatever else work was done either at tail end of 20th century and he's a top student no doubt, he studied it all and apparently applies things more than most can and is on cull level kills of elk each year etc. and I tried to point out what we're still missing to make this a far more objective topic. It's the end result of bullet as compared to the travel.

They were measuring all this internal damage and trying to make objective sense of it. When the bullet may be able to tell the story far more objectively and no one is measuring it. Final SD...which then gives you the starting point to then apply to distance traveled and can then use the energy figure to help explain that internal damage along side what's left of the bullet. Anyhow, those of us that do this for long time and have analytical minds (as many in a forum like this do) then we can feel our way through this better than most. The formula I outlined is currently the best simple way to properly apply(sd, construction, impact velocity - for game intended). But until we can actually come up with a standard of measure to put all bullets against each other, measure final sd, distance travelled, come up with sectional density reduction rates and energy reduction rates, over said travel, add in expansion and loss of mass perhaps etc. then this will remain a subjective mess. It has to be applied to all the known winners afield so comparison can be made, this would spur future bullet development. As you could imagine guys might have specific desires in penetration depth, energy shed along that depth, and expansion etc. so it may be discovered some holes in the market to be filled by manufacturers etc. Long bullets that do lots of shedding/expansion up front while keeping lots of mass in rear for penetration (a formula many of us love) in velocity ranges to match desired field ranges etc. Some guys may want something that only 25% of it opens up, little less expansion and loss for much deeper penetration and others may prefer 75% roll back, 3x expansion and shorter penetration for greater internal dump over that shorter travel. I digress...thinking outloud.

If I were Hornady or bullet manufacturer I'd break the budget for gel wide open and start crackalackin. First guy through the wall will get bloody (ask me how I know? ) but it will pay off in the end. I picked hornady to mention as they seem to be the most on the ball provider at the moment.

This is truly the only way to bring terminal ballistics knowledge and data to the same 21st century level of understanding as we have of the in-flight ballistics. IMO.

In the end, if this is developed, it would show why Bell did so well on those elephants with the 6.5 Mannlicher and why the 700 nitro express may get your azz turned into a grease spot in the dirt.