Ballistics Nerd Talk - SD Reduction Rate, Energy Reduction Rate

[Stinky Coyote]

Covid times are weird so lets have some weird ballistics talk.

Saw an interesting ballistic gel test recently, i took the data from it and looked at it from my weird perspective. Here goes...

This particular example was .264"(6.5mm) 123gr hornady eld-m, a pretty modern rapid expansion bullet with a great initial SD.

Initial Section Density of .252

2250 fps impact velocity (Equivalent of a 200 yard impact velocity launched from at a low to modest inititial velocity approx. 2500 fps)

1383 ft/lbs impact energy

19.7” penetration depth on ballistics gel

78.6% weight retention of bullet (96.66 grains)

Bullet mushroom textbook, core/jacket stayed together, mushroom cap peeled over itself to about the base of the bullet, max expansion at widest point was .645” and narrowest point was .547” for a .600” average expansion diameter. Original diameter .264”, expansion equals 2.27 times original, or 227%.

Final Sectional Density of the recovered bullet 0.038.(96.66 grains at .600" diam.)

Sectional Density Reduction Rate - 4.3% per inch.

Energy Transfer Rate – 5.08% per inch. (Dumped all 1383 ft/lbs into those 19.7" of penetration, 70.2 ft/lbs per inch)

This could show why 3rd class game recommends SD of .250 or higher with modern expanding bullets designed for hunting, not sure the number of inches one might consider for each class of game but nearly 20" with a 1383 ft/lb energy dump likely plenty adequate.

The more SD you start with the more you can lose as it does ‘work’, meaning it will simply do more 'work' than one that starts with less SD (given similar construction/expansion rate).

A delayed controlled expansion bullet will have; greater penetration depth, lower expansion ratio, lower energy transfer rate(less wound channel damage), higher retained weight, higher retained SD, lower SD reduction rate. Assuming all other things the same between a rapid expansion and delayed expansion bullet.

One should be able to create tables of hunting bullets based on this sort of data, combined with the known penetration depths for various classes of game (class 1 through 3 etc.).

Correspondingly see where certain bullets and impact velocity ranges meet to be recommended for each class of game. It would appear with all the current recommendations for initial starting SD with modern bullets that by trial and error things mostly were figured out, ie; class 2 game recommended .200 SD and higher, class 3 recommended .250 and higher etc. You get a certain depth of penetration range you can more accurately predict bullet performance compared to another bullet.

Bullet manufacturers could start to create bullets for specific SD reduction rates along the expansion scale from rapid to delayed controlled etc. perhaps? Possibly use a standard middle ground impact velocity, or two impact velocities which could then create a bullet profile along this scale and become even more useful in determining what all it can do?

Lets stay civil on this, genuine discussion, this is not a cartridge discussion or comparison. This is a ballistics discussion around terminal bullet performance potentials and new ways to compare as it relates to 'hunting'.

Any thoughts or ideas on this perspective? Any other interesting thoughts or perspectives on ballistics nerd talk?

Does this perspective allow the door to open for energy to make a reasonable applicable argument as a legit factor to consider additional to penetration?

[Stinky Coyote]

And to reply to my own weirdness, i guess where i'm headed with this is...

To help curtail the amount of argument on all this talk. It's fun but...

So if there's a new way to look at this, a new 'co-efficient' a new 'number'...that takes into account why a 416 on a mountain goat did very unimpressive work vs a .270 win that seems to flatten them with the opposite amount of impressiveness.

Some way to look at ballistics data that shows why the 416 would show that it could go through 8 goats with a moderate wound channel vs a .270 win flatten 2 goats with incredible wound channels.

There must be a new way to see the information we have. Come now...get in the game.

[glen moa]

So dump all energy and fall out the far side. But I don’t know how much bone I’m going to hit. So I need a bullet that will go though the toughest part on the biggest animal I might shoot. Now I need a big gun. And it will zip right though if I shoot a small animal.

[SnipeHunter]

For Cxp3 game, .264 is marginal. You need to go with 160gr and keep it to a couple hundred yards max so you have at least 1600 ft-lb energy.

[Chaoticelk]

I’ve never been one to chase bc or sd of a bullet I pick one usually Barnes or a Nosler and put it one round through the chest cavity and the work begins

[catnthehat]

Originally Posted by Chaoticelk

I’ve never been one to chase bc or sd of a bullet I pick one usually Barnes or a Nosler and put it one round through the chest cavity and the work begins

This makes a heckuva lot more sense than fussing about crap on charts and and stuff that just complicates things.

I grew up with a professional ballisticion, a very practical one too believe it or not!
His basic response to me when I was very young and asked him what the best cartridge was for hunting big game ? " 180 grains and .30 calibre Son, don't complicate it."
30/30, 308, 300 savage, 300 mag, just put it in the right place and break out the knives.
Now that was about 60 years ago, but today one can still keep things basic without getting all tied up in ballistics gobblty goop.
A little knowledge goes a long way, too much just complicates things.
There is a threshold for sure when it comes to cartridges, but anybody who professes to know anything about cartridge ballistics knows that the 25/20 is not a deer cartridge in Alberta, and also knows that with the right bullet a 243 or a 7mm mag will not blow a white tail to pieces.
Cat

[Chaoticelk]

I’m also a believer cartridge selection don’t matter I’m a believer if you know how to shoot and put bullet where it needs to be. And elk deer moose from 0-300 isn’t going to know the difference. We have killed elk and moose with 243,25-06 the smaller of two and up to 338 win. Never once seen a difference in killing, between my father and grandfather and me that’s over 40 bull elk and 20 moose my personal favourite is now 7mm08 in x bolt

[Stinky Coyote]

Originally Posted by Chaoticelk

I’m also a believer cartridge selection don’t matter I’m a believer if you know how to shoot and put bullet where it needs to be. And elk deer moose from 0-300 isn’t going to know the difference. We have killed elk and moose with 243,25-06 the smaller of two and up to 338 win. Never once seen a difference in killing, between my father and grandfather and me that’s over 40 bull elk and 20 moose my personal favourite is now 7mm08 in x bolt

Yes, pretty tough to argue with dead, and most critters couldn't tell the difference. Could not agree more. What i think we can do better is tell the story of 'why'.

Mostly we still rely on 'opinion'.

What spurred this latest quibble was looking into the pc carbine thing for fun. Just researching the ammo alone was where it got interesting. This is a whole new world and they obsess this defense performance stuff to death, literally. They try to design performance to fbi standards in the gel, 12" min - 18" max, with good expansion. Obviously their criteria cite heavy clothes, automobile glass etc. but it's just not something i had looked at too much before because i only care about hunting and ballistics associated with that.

My immediate thought is why in tarnation haven't we hunters, and or, big game ballisticians not come up with some formulas, standards, measures in a similar fashion? Not to tell you what's best, but to show you the differences. Then apply all our 'opinions' and 'experiences' (collectively or otherwise) to the more standardized data and measures we could be producing?

We know that a lot of elephants died with some pretty little high sd solids from 6.5's and 7's...we know they did it on their sd and obviously they had to maintain that sd the whole way through or good luck lucy.

We have millions of examples of these real man cartridges doing pretty sub par work on smaller game when by all accounts they should have turned the animal into a canoe. Inversely we have so many examples of 'that's not enough cartridge' absolutely flattening critters like the hammer of thor.

A guide took a good one from a hunter in africa through the shoulder or some shizzo and survied (from recollection)?, and thankfully it was simply far too much cartridge for a little fart right? (probably wasn't a little fart, but for that cartridge he was a little fart so it just poked a hole and did all it's 'work' elsewhere)

We still mostly explain all this stuff with...'you can't go wrong with 180 out of a .30'.

Really? That's what we're gonna keep going by?

I'm sorry but isn't this 2020?

Show me...or i will show you.

Seriously, it's time for better data.

Where my nerds at?

Boddington will be writing about this in a month or two...lets fill this thread up so he has a little more to go on. (he lurks, i know he does)

[catnthehat]

Tell me what is wrong a 180 grain out of a .30 whatever?
Discussing ballistics within A certain cartridge makes sense to me, adding different cartridges into the mix does not fit the simple fact that all those elephants could have been killed with a plethora of solids not just the 7mm and 6.5mm this is another thing that has stuck with me that was told to me by the same professional ballisticion - whose favorite cartridge BTW was NOT a 30 BTW but a .311 which many consider an inferior caliber let alone the cartridge most shooters associate it with .
Cat

[Stinky Coyote]

Originally Posted by glen moa

So dump all energy and fall out the far side. But I don’t know how much bone I’m going to hit. So I need a bullet that will go though the toughest part on the biggest animal I might shoot. Now I need a big gun. And it will zip right though if I shoot a small animal.

Another valid point, of course there's going to be a difference between animals and gel...but where the gel will shine is showing the differences between the bullets. That's the key. If you want to end to end elk, you would be able to see it all in the the data, not the 'that should do it' opinion stuff. There's reasons that bullets go through things as far as they do and as leave the amount of damage they do. If you maintain your SD you need lot's less impact velocity to keep on driving through. If you up your impact velocity you create more wound channel damage to go with. You get shat ratio's of either for game intended and you get shat terminal performance. You can go too far both ways, too much speed, not enough sd, or too much sd and not enough speed.

The expansion of bullets through game is brilliant. This is the future of ballistics imo. To be able to control an expansion predictably through intended targets to be able to dump all the energy and increase wound channel factor will be very efficient.

So you're going to want to measure these factors, understanding them will sell them (from a marketing/manufacturing standpoint), but end of day the performance afield will be far more predictable, far less surprises and or 'opinions'.

The old saying 'right tool for the job'.

It's the bullet that does the 'work', what drives it has always been nearly irrelevant.

[Stinky Coyote]

Originally Posted by catnthehat

Tell me what is wrong a 180 grain out of a .30 whatever?
Discussing ballistics within A certain cartridge makes sense to me, adding different cartridges into the mix does not fit the simple fact that all those elephants could have been killed with a plethora of solids not just the 7mm and 6.5mm this is another thing that has stuck with me that was told to me by the same professional ballisticion - whose favorite cartridge BTW was NOT a 30 BTW but a .311 which many consider an inferior caliber let alone the cartridge most shooters associate it with .
Cat

Cat, you're pointing out exactly what i'm talking about. There are a million people saying you can't go wrong with a 180 out of a 30. Why? Simply because it works? And...you, the million people, including the old ballistician...are not wrong. We can keep going like this, and we will keep going like this lol.

What i'm saying is...we can do better, do you not agree there's room here?

[32-40win]

Stinky, youse must be one of them blasted gun nuts, I think I see where your line of thought is, and it's a fun one for the usual nitpicky debate that gun nuts like to pursue. Not sure I have seen a gel test with a bullet that didn't perform wonderfully. There were a couple of vids around somewhere with bone or something mixed in, found those a bit more interesting. Down the road a person shud test the new fmj rounds that Hornady will be loading for the military, see what they do. I have a supply of beef soup bones in the yard to mix in, about an orange garbage bag full, winter accumulation from the hound.

[catnthehat]

Originally Posted by Stinky Coyote

Cat, you're pointing out exactly what i'm talking about. There are a million people saying you can't go wrong with a 180 out of a 30. Why? Simply because it works? And...you, the million people, including the old ballistician...are not wrong. We can keep going like this, and we will keep going like this lol.

What i'm saying is...we can do better, do you not agree there's room here?

As I stated earlier , discussing the ballistics of a certain cartridge makes sense when comparing the different bullets for a particular cartridge.
That is where it ends for me .
I believe in proper shooting practise over everything .
Cat

[Stinky Coyote]

Originally Posted by SnipeHunter

For Cxp3 game, .264 is marginal. You need to go with 160gr and keep it to a couple hundred yards max so you have at least 1600 ft-lb energy.

Not a bad 'opinion'. I could easily agree with this statement. You certainly won't be under gunned. But this same 160 gr bullet impacting the same critter at the same velocity but one option is rapid expansion going to nearly 2.5x original diameter and dropping SD like a mofo...vs a 160 gr solid, where there is no expansion and the SD remains the same the whole way.

We know the latter option can get deep enough into into an elephants head at a moderate velocity to turn the lights out forever.

Now, for hypothesis sake lets say that option goes 16" through that much hide/bone/brain of elephant head (but double that of regular ungulate).

What does the rapid expansion option do? Well, lets say we could produce 3 different expansion rates to consider, that would go 25%, 50%, 75% as deep as the 100% solid? What if you could design that in to the bullets? What if you could measure that consistently compared to the other bullets? Well we can, we just don't...yet.

Maybe the 25% option expands to 4x if not fragments a ton, retains less than half itself as it explodes within, and penetration at 4" through elephant head but double that on normal critters, so good small game/varmint type bullet. Lets look at option #2, can go through 8" of elephant head or 16" of regular critter, expands plenty, retains half itself, great class 2 deer option 3...well there's your class 3 elk/moos option or 12" of elephant head, or 24" of regular critter, retain 75% or better weight, expand maybe 2x tops etc. Wound channels all corresponding, dumping as much energy as you can for game intended.

Just making examples and hypothesis here for discussion purposes.

We are doing all the above, we are just doing most of it with the swag principle. We all know what that is right?

[Stinky Coyote]

Originally Posted by catnthehat

I believe in proper shooting practise over everything .
Cat

I will always be on board with this. Shot placement trumps everything else. When you get that right, you can get away with surprisingly little sd or otherwise.

Let's assume for discussion purposes that we are hitting our targets well.

Well technically we are talking about comparing the bullets at 'set' impact velocities through set medium (gel) to show differences between them.

The cartridge that drives it is irrelevant. The bullet construction and design, plus impact velocity, and sd, determine everything, not the head stamp.

The head stamp just lets you know the range at which you can do 'work' with the bullet that's attached to it, for any given class of game, or otherwise.

[Stinky Coyote]

Originally Posted by 32-40win

Stinky, youse must be one of them blasted gun nuts, I think I see where your line of thought is, and it's a fun one for the usual nitpicky debate that gun nuts like to pursue. Not sure I have seen a gel test with a bullet that didn't perform wonderfully. There were a couple of vids around somewhere with bone or something mixed in, found those a bit more interesting. Down the road a person shud test the new fmj rounds that Hornady will be loading for the military, see what they do. I have a supply of beef soup bones in the yard to mix in, about an orange garbage bag full, winter accumulation from the hound.

I do call myself a ballistics nerd all the time, i do enjoy it and find it fascinating. I'm all for whatever medium can be easily replicated to create a comparison database between hunting bullets that will more accurately predict performance than the way we currently predict performance.

I'm thinking gel will be the winner. The fbi and whoever uses pistols for defense reasons have a good idea and system developed for gauging their needs and potentials. We hunters haven't followed suit nearly as well.

[catnthehat]

Originally Posted by Stinky Coyote

I will always be on board with this. Shot placement trumps everything else. When you get that right, you can get away with surprisingly little sd or otherwise.

Let's assume for discussion purposes that we are hitting our targets well.

Well technically we are talking about comparing the bullets at 'set' impact velocities through set medium (gel) to show differences between them.

The cartridge that drives it is irrelevant. The bullet construction and design, plus impact velocity, and sd, determine everything, not the head stamp.

The head stamp just lets you know the range at which you can do 'work' with the bullet that's attached to it, for any given class of game, or otherwise.

Read my entire post again not just the part you quoted and let that sink in.
It was not that long ago you were arguing that certain 6.5 cartridges were superior to other 6.5 cartridges and I stated that the cartridge had no bearing on a 6.5 bullet coming out of a muzzle at a certain velocity with you saying no I was wrong .
Now you are contradicting yourself saying the cartridge does not matter .
I should know better than respond to any of your drivel .
Done here .

Cat

[Stinky Coyote]

Originally Posted by catnthehat

Read my entire post again not just the part you quoted and let that sink in.
It was not that long ago you were arguing that certain 6.5 cartridges were superior to other 6.5 cartridges and I stated that the cartridge had no bearing on a 6.5 bullet coming out of a muzzle at a certain velocity with you saying no I was wrong .
Now you are contradicting yourself saying the cartridge does not matter .
I should know better than respond to any of your drivel .
Done here .

Cat

I only quoted what i agreed with lol. This is simple, you believe discussing the cartridge itself is more important. I believe it's irrelevant. So we are definitely done discussing things and we can agree to move on.

You're trying to turn this into a cartridge or caliber discussion, that's not what this is. I simply used a recent data set i saw for an example. This isn't a 6.5 crusade fyi. Sure it's an over achieving sob...it's the 'why' part that i find interesting. There's more to it than just being 'heavy for caliber'...but you can make all other cartridges/calibers over-achievers also if you just apply that simple formula of 'heavy for caliber'.

Earlier i argued ft/lbs was a useless measure, this is the only thing i think i'm changing any tune on. I think if we look at the data right, it can help explain what i'm talking about here. We always say it's better to dump as much of that 'energy' in the critter as possible, i agree. A 6.5 does it's over achieving not by being a 6.5...but by having unusually high sd giving it an advantage over other options with less. That's it. I could care less if it's thrown from a grendel, creedmoor, prc, 55, win mag, .284 etc. The headstamps just change the distances with which the bullet can do it's 'work'.

I appreciate most options for what they are i just reduce them down to things other than the headstamp in order to relate them to one another. I appreciate the sd and bullet construction for intended targets above head stamps or calibers. So lets discuss that stuff. We've done the cartidge/caliber debate stuff to death...everyone knows you can't go wrong with a 180 out of a 30.

[Stinky Coyote]

there could be a future where instead of us saying 'well you want x amount of ft/lbs for this size of critter'

or 'you need this amount of sd for this size of critter'

we could/should get to a point where we say things like 'well you'll want to find something that does at max intended distance, 20" of penetration, with 100 ft/lbs per inch, and 2.5x expansion rate, for that class of game'? or...

'you'll want to find something that goes 20", with 8% energy transfer per inch, and 5% SD reduction per inch'

something a little more specific than how we currently speak the vague languages...

[elkhunter11]

Originally Posted by catnthehat

This makes a heckuva lot more sense than fussing about crap on charts and and stuff that just complicates things.

I grew up with a professional ballisticion, a very practical one too believe it or not!
His basic response to me when I was very young and asked him what the best cartridge was for hunting big game ? " 180 grains and .30 calibre Son, don't complicate it."
30/30, 308, 300 savage, 300 mag, just put it in the right place and break out the knives.
Now that was about 60 years ago, but today one can still keep things basic without getting all tied up in ballistics gobblty goop.
A little knowledge goes a long way, too much just complicates things.
There is a threshold for sure when it comes to cartridges, but anybody who professes to know anything about cartridge ballistics knows that the 25/20 is not a deer cartridge in Alberta, and also knows that with the right bullet a 243 or a 7mm mag will not blow a white tail to pieces.
Cat

Well said.

To carry that further, complicating things to the point of trying to tailor a load for every shot situation, will just add confusion. You could carry a handful of loads , with different bullets, to try and use the optimum bullet for each animal, and each shot distance, but unless you are hunting only one species, over bait to control the range, it would be totally impractical. Not only would you have to compensate for different trajectories for each load, but do you really want to have to have to select a load and then load your rifle after you find the animal? That would be time consuming, and would result in lost shot opportunities.

[Pathfinder76]

The more game I shoot, the less I know. I’ve found the opposite to be just as applicable.

[Buckhead]

Here is all the hunting bullet info you will ever need.

https://www.rifleshootermag.com/edit...s-market/83865

Just pick the one that is most accurate in your rifle and go hunting.

[Stinky Coyote]

Originally Posted by elkhunter11

Well said.

To carry that further, complicating things to the point of trying to tailor a load for every shot situation, will just add confusion. You could carry a handful of loads , with different bullets, to try and use the optimum bullet for each animal, and each shot distance, but unless you are hunting only one species, over bait to control the range, it would be totally impractical. Not only would you have to compensate for different trajectories for each load, but do you really want to have to have to select a load and then load your rifle after you find the animal? That would be time consuming, and would result in lost shot opportunities.

Hear this, and agree, but like selecting we do now we tend to make sure we've got plenty for all the game we want to go after at all the distances we want.

I think we can get our cake and eat it too. Adding length to these bullets so sd remains to ensure desired penetration...at the same time we can add more expansion to maximize energy dump/damage along the way.

We are doing that with expanding bullets already but it's more of a black art.

Ie; i love more rapid expansion bullets driven at modest velocities...for terminal performance on game, similar to the initial example, others would forgo the expansion part to drive twice as deep etc. the desires won't be any different between us, we will just have better data for which to choose from

The example above happens to be what i shoot and it's far from recommended hunting option yet it gives me exactly what i want and prefer. So if it was looked at with more technical comparisons to other options the box could be more aptly labeled. This option out performs the SST option, it stopped short of 18" and it's the designated 'hunting' option lol. So clearly we aren't accurately presenting what these things can do and in 2020 i think we can do much better.

[Stinky Coyote]

Originally Posted by Buckhead

Here is all the hunting bullet info you will ever need.

https://www.rifleshootermag.com/edit...s-market/83865

Just pick the one that is most accurate in your rifle and go hunting.

Yup this works too. A little more technical way of saying 'a 180 in a 30' will do the trick.

There's just so much more to it, there's more info to be had, there's better ways to look at this. Which will lead to even better bullet selections that are more versatile than existing options. Getting the benefits of both types of bullets (rapid expansio/delayed controlled expansion) into single bullets...have your cake and eat it too.

Currently, as i said above, one has to buck the trend a little to do this. One has to shoot unusually high sd bullets with rapid expansion construction at moderate velocities and you get fantastic performance. Yet what i shoot currently is like a ballistic tip, a-max...most consider 'deer' only at best type bullet or maybe steel and targets only...as that is how it's marketed. Yet it's an over achiever on game for reasons we don't look at currently.

The performance above from that little 123 gr load could embarrass lots of the 'existing bad ass' stuff we keep going on about. And maybe that's part of the resistance to what i'm talking about here? 1. No one wants their ballistics world as they know it to be changed. 2. No one wants their pet choices to be shown up by some new kid on the block or what was previously considered 'a girls choice' lol.

Obviously none of that matters to me, but it does for a lot people, i'm about the numbers, data and performance. Yup, you can't go wrong with most choices as long as you do your part, all pretty well proven. We can carry on like this for eternity. We could also see it better and advance the choices better.

[Dean2]

SC

This whole ballistics discussion and interest therein boils down to why do I shoot and hunt. Some like the arcane and mystical pursuit of unusual solutions to problems. For them the discussion of SD reduction rates, impact velocities, atmospherics and Coriolis effect are all germane and endlessly interesting. This is particularly important to those that shoot and/or hunt at long range.

For 95% of hunters that shoot all their game under 300 yards and 90% of that at 150 or less; they shoot to get game and eat wild meat. For them simple is the right solution. Take a big enough gun with a heavy enough, well constructed bullets, put them in the right spot and that is all they care or need to know about ballistics.

If you want guys to engage on this discussion my bet is that the Long Range Hunting Forum would have many more interested takers.

https://www.longrangehunting.com/forums/

By the way, shoot that same 6.5 with a 160 grain bullet and you won't have to worry about SD reduction rate.

[huntingfamily]

Some good bed time reading,

https://www.ballisticstudies.com

[Stinky Coyote]

Dean2 you are likely right. I like our little corner of the interweb and to keep our pages relevent and fresh also.

I bet the long range guys speak this quite a bit more fluently. I wonder if some of the numbers i presented this go round, and even alluded to the last go round, are something they are discussing over there? Hmmm

I have no doubts about my gear and it's limits, i'll use it just fine, and also have first hand that corroborates what i'm talking about here and mirrors that gel test too. A moose and a deer same day, same range, same recovery distance. The thin little deer took moderate damage as it was an easy pass through, pretty typical of anything on a 125 yard broadside through the soft, and then my moose quartering towards ate every ft/lb and got the works from that gel test, and the inside damage was as impressive as i've seen on a big game critter, that huge liver had an 10" long, full depth and thickness of liver, section of straight hamburger. I didn't see bullet exit so likely in guts offside i didn't go fishing for it, caught some lung etc. on way in. Anyhow, you open that moose up and then look at the little cartridge and bullet that did and as Chuck said...the more you do this...

High sd bullet with rapid expansion characteristics can give the best of both worlds. It can increase it's versatility by being able to get the job done through a wider range of parameters, in close, long range, smaller critters, larger critters...and do so with more noticeable performance. Than say just going safe with a delayed controlled round that's really only going to strut its stuff when you need to end to end a large thick critter.

[Stinky Coyote]

Originally Posted by huntingfamily

Some good bed time reading,

https://www.ballisticstudies.com

this does look like good bedtime reading, muchos gracias

[Stinky Coyote]

Originally Posted by Stinky Coyote

This particular example was .264"(6.5mm) 123gr hornady eld-m, a pretty modern rapid expansion bullet with a great initial SD.

Initial Section Density of .252

2250 fps impact velocity (Equivalent of a 200 yard impact velocity launched from at a low to modest inititial velocity approx. 2500 fps)

1383 ft/lbs impact energy

19.7” penetration depth on ballistics gel

78.6% weight retention of bullet (96.66 grains)

Bullet mushroom textbook, core/jacket stayed together, mushroom cap peeled over itself to about the base of the bullet, max expansion at widest point was .645” and narrowest point was .547” for a .600” average expansion diameter. Original diameter .264”, expansion equals 2.27 times original, or 227%.

Final Sectional Density of the recovered bullet 0.038.(96.66 grains at .600" diam.)

Sectional Density Reduction Rate - 4.3% per inch.

Energy Transfer Rate – 5.08% per inch. (Dumped all 1383 ft/lbs into those 19.7" of penetration, 70.2 ft/lbs per inch)

To keep all the data in one place, i didn't likely show it fully, and maybe this stimulates other ideas on how to view the data?

Start SD .252 (100%)
End SD .038 (15%)
Difference .214 (85%)
Depth Achieved 19.7"
SD Reduction Rate (0.01 per inch, or 4.3% per inch)
Energy Reduction Rate (70.2 ft/lbs per inch, or 5%)
Expansion Ratio 2.27x

When i see the above data it's good but where it will excel is when you can compare it to all the hunting bullets we want to look at. Including the old standards we know and from which to get our baseline goal posts.

This will be helpful for so many reasons, from choosing a light hitter for kids to finding the ultimate long range choice, or the deepest penetrating choice, or the most explosive choices etc.

Looking at the amount of SD lost .214...lots of deer bullets don't even start with that to begin with, so, would be interesting to see some bullets from .200 initial SD range and where they end up in comparison. Or inversely ultra high SD bullets that start a .300 and up.

The Expansion Ratio, and the Energy Reduction Rate (I'll coin it now as ERR), the SD Reduction Rate (SDRR) will inadvertently show within the SDRR but still nice to see for quick glance purposes if you're looking at comparable bullets, or to meet personal minimum preferences of 1.5x expansion, or 2x or 2.5x...for example. So many goal posts can be set.

The SDRR combined with penetration depth, looked at in 'per inch' format, would tell a far more technical story. This would remove a lot more of the 'just throw a 180 out of a 30' and allow you to find even more versatility and performance than you could before...without having to go shoot animals to see, or go by opinions. We have a huge data base of bullets and impact velocity ranges for which we know to work, to form the base data for all comparing. When you have the benchmarks you can then start to develop bullets to achieve better performance...to hit a greater variety of goal posts.

Ya this discussion could be on a more technical forum, but i'd rather it start here. The discussions that happen here helped guide the process anyway.

Hornady, how's your budget for ballistics gel? Let's get crackin.

Anyway, if the 'per inch' format isn't the way to look at it...anyone have other ideas of format potentials?

[marky_mark]

Why dont you just spend more time at the range practicing
Theres no such thing as perfect