I am new to the world of giving a hoot about the particulars of bullets and bullet performance. I have really only messed with FMJ and OTM, for the entirety of my time spent with the shooting hobby. As the title states, I am curious how one determines the maximum ranges that bullets will perform as advertised. More specifically, I am curious how we determine what seems to be referred to as the "expansion floor" of various factory loads. I am aware that velocities advertised on the box are largely irrelevant, as they are often obtained with longer-than-typical barrels. I have a chronograph, with which to obtain muzzle velocities, and potentially velocities out to 100yd, if I am confident in the repeatability of the weapon system on a particular day. To narrow the scope of the conversation that much more, I am more specifically concerned with this information when it comes to the following three loads:
Hornady Black 5.56 HD/SBR 75gr Interlock
Hornady Critical Defense .223 73gr FTX
Barnes VOR-TX 5.56 70gr TSX
In my searching so far, I have turned up second hand info on expansion floors for two of these:
75gr Interlock- 1500fps
70gr TSX- 1800fps
I also found a discussion in which someone put info into a ballistics calculator, for the TSX, to determine the velocity at various ranges, out of a few different barrels. His findings showed the TSX staying above 1800fps out to 300m, out of an 11.5" barrel. For that bullet to perform as advertised out to that range, from a barrel that short seems quite impressive. These "expansion floors" seem somewhat iffy, as the manufacturers apparently aren't crazy about publishing them, and those who have numbers got them from a "Hornady rep", or some other such source. I am curious about velocities at various ranges of these loads out of 10, 11.5, 12.5, 14.5, and 16" barrels.
Also, is there any value in, we'll call it, redneck terminal performance evaluation? It seems more reliable to assess the terminal performance by shooting at something like ballistics gel at range, than by relying on speculative expansion floors and potentially shooting a chrono. But, I am not going to make ballistic testing media, or purchase it; the commercial clear stuff seems largely useless anyway. Folks have been making gallon water jugs blow up for as long as we've had gallon water jugs; can this be used as any sort of realistic indicator of performance?
I'll add more to this later, but I wanted to get it started, to see if any immediate feedback proves the whole thing misguided. Like I said, I am new to the whole ammo thing, so take it easy on me. Thanks!

One relevant article was posted by Recoil years ago. It has some good info, but is tainted by the seemingly irrelevant clear ballistics gel. https://www.recoilweb.com/sbr-...rs-guide-141394.html

This guy (Molon) has multiple excellent ammo assessments on multiple forums. https://www.m4carbine.net/show...-Barnes-70-Grain-TSX

The discussion with mention of the expansion floor and velocities at range of the 70grTSX. https://www.m4carbine.net/arch...ex.php/t-208857.html

quote:

Originally posted by KSGM:
Folks have been making gallon water jugs blow up for as long as we've had gallon water jugs; can this be used as any sort of realistic indicator of performance?

Only to the most limited degree.*

If we want to demonstrate that a bullet fired from a 16 inch 5.56mm barrel can cause more disruption and damage to an animal target than a 9mm bullet from a handgun, shooting water jugs will do that very effectively. I used water jugs just a couple of days ago to show that my agency’s 223 expanding bullet duty ammunition has a different effect than an FMJ load. The difference was not huge, but it was apparent to all who saw the test.

For the type of information you’re seeking, though, I consider shooting at plastic containers filled with water to be a waste of ammunition. There are ballistic test mediums that are much better, but of course they are much less convenient to use. The best thing is to try to find tests others have conducted. I also believe that if manufacturer expansion data at different ranges (velocities) are available, they can probably be trusted.

And yes, I also trust ballistic calculator data for velocity information and that’s easy enough for anyone to experiment with. For example, the 16" muzzle velocity I’ve measured for an M193 load was 3040 fps; the same load from 11.5 inches was about 2707 fps. According to Applied Ballistics under “standard” atmospheric conditions at 500 yards the 16" load would be traveling about 1483 fps; at the same distance the 11.5" load would be at 1268. Why 333 fps difference between the two lengths at the muzzle, but only 215 fps at 500 yards? Because drag effects are greater at higher initial velocities.

As for ballistic performance, i.e., expansion, shooting at a good test medium at the range in question is the obvious solution. Sometimes experimenters load ammunition to lower velocities and shoot at shorter distances. It can be difficult to get a good center hit on a 6×6 block of gel at 300 yards with an AR-15. The problem with starting with a lower MV is that the spin rate of the bullet is also slower, and some people believe that has an effect on terminal ballistics. I doubt that it’s that important, but what do I know?

I watch a lot of YouTube tests of ammunition, and a few are good, but many are marginal to laughable. Unfortunately, though, I know of no other accessible source for some information.

As for test mediums, keep in mind that even the good stuff is an artificial substitute for living targets. To cite just one example, the US Army was the first agency I know of that explored using gelatin for terminal ballistics evaluation back in the late 1940s, and they used 20% gel, not the current 10% standard. They came up with that medium after conducting live fire experiments on living (anesthetized) animals.
Why the change was made (by the FBI?) from 20% to 10% I’m not sure, but I suspect it had something to do with the fact that some bullets didn’t perform as well in 20% as some experimenters thought they “should.” I’ve seen only one YouTuber using 20% gel for his tests, and whether it’s more valid or not, his results can’t really be compared with other people’s.

Anyway, I will be interested in following this discussion to see if it turns up anything more than I know all ready.

* And only with certain types of bullets. Trying to evaluate the performance of hollow point handgun bullets by firing through the hard plastic shell into water is … not wise. Other types of bullets, though, will be less affected by the plastic.

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I watch a lot of YouTube tests of ammunition, and a few are good

Can you recommend a good one?

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but I suspect it had something to do with the fact that some bullets didn’t perform as well in 20% as some experimenters thought they “should.”

Hahaha; that sounds about right.

Boot camp question. Maximum effective range of an M16 is 550 yards. Despite that, I damn sure wouldn't want to get hit with one at 600 yards.

If I find any videos that I consider to be halfway decent, I’ll post their links here.

This is one I consider to be in the decent category. The tester evidently uses genuine “ballistic” gel and gives us both the velocity and retained weight of the bullet along with a good measure of the total penetration. He also at least turns the gel block around after the first shot to help avoid the second bullet’s going through disrupted medium. Most testers don’t seem to have even that much common sense to do that.

https://www.youtube.com/watch?v=2lkI36eUoy4

As I’ve complained about here before, though, that guy insists on using two less common barrel lengths for his tests: 11.5 and 20 inches. Why he can’t get and use a cheap 16 inch upper if he really wants people to follow him is beyond me.

I have settled on the Speer 75 grain Gold Dot load for certain personal purposes and it would mostly be fired from a 16 inch barrel. I am, however, not especially concerned about its performance at longer ranges, and definitely not how it performs through windshields at long ranges.
If someone who needs to be shot is 100 yards (not to mention farther) from me, I’ll be happy if it pokes a hole in him. “Well, if it performs out of a short barrel, we can be sure it will do well out of a longer barrel”: Probably, but why must we make assumptions?

On the other hand, if someone is interested in short barrel and long range lower velocity results, the 11.5" data is useful, so I rate that video and his other videos higher than many others for that and the other reasons I mentioned above.

As an aside, he does use Clear Ballistics for the windshield test. Although one of your linked articles mentions the flaws of CB, other than the common “rebound” effect that’s seen with the medium (and is usually ignored by testers), from what I’ve seen in other tests I don’t consider it to be worthless—and certainly not in the water jug category. A bullet with a tiny open tip may not expand in the stuff, but other bullets seem to perform pretty much as expected.

As a last comment, I tend to get a little bemused by all the people who will look at anything over 18 inches of penetration in bare gel as a failure of some sort; one guy whose videos I finally gave up on paying any attention to flat out pronounced anything with >18" of penetration as totally unsuitable for defensive purposes. And similarly, if it penetrates 12 inches, it’s okay, but if one shot penetrates to only 11 7/8 inches, then it’s no good and should be avoided.

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wouldn't want to get hit with one at 600 yards

I share that sentiment.

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if someone is interested in short barrel and long range lower velocity results, the 11.5" data is useful

I do find that info valuable, as it applies to my current medium range precision rifle brainstorm.

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pronounced anything with >18" of penetration as totally unsuitable

I don't see myself getting too wrapped up in overall penetration depth. I consider most of my AR projects in the context of, we'll call it, "open warfare", as opposed to home/self defense. So long as it has dramatic effect in that first twelve inches, I don't reckon I care how far it keeps going.

Historically, and currently, for the most part, I agree with Gustofer's outlook. However, my curiosity has recently been piqued by an acquaintance who depopulates wild pigs semi-professionally. He experiments with a lot of different ammunition in relatively consistent and repeatable circumstances, on actual living animals. I trust his feedback, and it's certainly intriguing to hear about how "X" rounds drop a pig in it's tracks, while "Y" do not. He speaks highly of the TSX bullets, while making the joke that if he is using MK262, he can expect the pig to die about 262 meters away from where it was hit. While poking holes is just fine (nothing that lives ought to have holes in it), there is a definite appeal to the "dead right there" potential performance of something different.

**This is a one-time double post, to move the following posts over to this thread, while not making the former thread confusing, by deleting it entirely.**

As with most of my gun-related endeavors, I'll be forced to chip away at this a little at a time, and usually under less-than-ideal conditions. That being said, I was able to do some test-runs on the chrono setup; I used 55gr to do this testing, and to bring the zero in on the recently assembled prototype "mini recce" at the same time.

I logged two five-shot groups at the muzzle. The two averages were 2657fps and 2703fps. Second group difference due to heat, I suppose. I then moved the chrono to the target (about 5m shy of it, due to a terrain requirement), and fired one more group. Unfortunately, only one of the five shots at the target was captured; it was 2331fps. I suspect this is due to the target being in the shade, while the shooting position is in the sun. The day was uniformly overcast to boot, but not excessively dark. Perhaps a sunny day will have enough light hitting the hoods, when positioned at the target.

The chrono setup is a Pact with the hoods 24" apart.

Again, this is not with the ammunition that is ultimately the goal here, but I wanted to share the test run with folks.

Smudge's thread inspired me to break out the 933, so I figured I'd shoot some 77gr SIG OTM through it, and the chrono, to gather some accuracy and velocity data. Accuracy was nothing worth writing about. Velocity came in the form of a six-shot average at the muzzle (I got trigger happy), and a three-shot average at the ~95m position. There's a bit of a story there: I loaded ten rounds, with the intent to fire two five-shot groups; lost track on the first group, leaving me with four shots to average at the distant measuring position; it's sunny today, and earlier in the day, so more light was on the hoods, and all the shots were captured. But wait, I said a three-shot average, and all the shots were captured, but I fired four! I missed the chrono aperture on my third shot; I knew it when it happened, and it barely touched the hood strut, but was thrown about six inches away from the rest of the shots, and key-holed. I thought that was a pretty big deviation in the distance of about five meters, between the chrono and the target. I remember Sigfreund doing some tests with skewers and dowel rods, and seem to recall he didn't see much deviation; so, I thought it was a neat data point, and I am glad it didn't ruin anything.

Readings for 11.5" shooting SIG 77gr OTM:
Muzzle: 2566
100m: 2334

As expected from a heavier, nicer bullet, than the previous run with the 10" gun and 55gr, the initial velocity was lower, but less was lost. Still, I think I recall reading that the fragmentation floor for MK262 is 2300fps; so, if we say this bullet is similar, that's about all the range you'll get out of it, while retaining performance.

I'll chip away some more another day. I promise I'll shoot some of the actual test subjects next time.

quote:

Originally posted by KSGM:
I remember Sigfreund doing some tests ....

For anyone interested, this was the thread.
https://sigforum.com/eve/forum...780026494#8780026494

And a post in that thread by forum member fritz was actually more significant than mine.
My tests and the one he referred to involved shooting 308 Winchester bullets that were much heavier and less likely to be deflected than a 77 grain 223.

I bought a 10.5" Noveske barrel. This is the barrel that the velocities will be measured out of, from now on. Unsure how long it'll take to get here; it said it was in stock, but they also say 2-4 weeks for order processing. I won't waste any ammo in the meantime.

Remember the idea of when you wound an enemy you may remove 3 from the fight? That’s the wounded combatant, then two to help him? Again, situations vary.

Maybe that theory doesn’t always hold water, but much of the fight ‘could’ be out if the wounded individual. It’s different than elk hunting, where you don’t want a wounded animal to run off.

I’ve been in a few pest scenarios, coyotes & pigeons of all things. I was limited in what I could use. Not that I condone it, but after being hit with less than ideal energy, I still knew they’d never be back. That was the 17 HMR for the coyote & 500 fps 20 grain bullets for the pigeons.

So skimming through the scenarios mentioned above, hits themselves could accomplish most of the goal

This may or may not be relevant to the discussion, but I'm getting 2340 FPS at 200 yards and 1940 FPS at 300 yards with 75/77 gr .223 target loads out of a 20" barrel.

So I finally attempted to gauge terminal performance of the 73gr FTX at 300M. I bought a 5LB piece of pork, with a bone in the middle of it; it was the biggest piece of meat the local store had, that didn't break the bank. I left it on the Styrofoam tray, in the plastic wrap, and put it on top of a cardboard box. My hit was about 1/2" from the very bottom of the chunk, which sucks. I didn't have time to re-engage today, but there's enough meat left that I can.

It knocked it off the box, and it deformed the top of the box. It did hit the bone, so I suspect that had a lot to do with it sailing off the box. Unfortunately, I have no FMJ comparative data, so this is somewhat inconclusive. I hope to learn more from a more centered hit.

Follow-up: In another session, I managed to get a decently-centered hit. Perfect, elevation-wise, and just off to the right. It knocked it off the box again. Part of the bullet made it's way all the way through, as I heard it hit the steel plate behind the meat, and I could see the impact on the steel, upon closer inspection. I am not a learned terminal ballistician, so I am using these other terms loosely: The "wound channel" seemed to be about the diameter of a quarter, all the way through the ~8 inch thickness of the piece. There was also what appeared to be a potential offshoot channel, about 2/3 of the way through, coming out the side. I did recover part of the little plastic FTX center "plug" from the meat. There was not any evidence of massive initial "cavitation". Again, the lack of a comparative FMJ experience, and less-than-average understanding of terminal performance in general, makes this information difficult for me to draw any conclusions from.

There is much about wound ballistics I don’t know, but a few comments. (Yes, another dissertation. )

Cavitation, i.e., formation of a temporary cavity in flesh caused by the passage of a projectile does occur. This was demonstrated during experiments that were reported in the 1962 publication, Wound Ballistics, prepared by the Office of the Surgeon General, Department of the Army. The testing involved anesthetized animals, animal parts, and then 20% gelatin as a tissue simulant. The process through animal flesh was photographed by high speed X-rays. Those experiments are the first I’m aware of that looked at the effects of high speed projectiles on flesh.

Later experimenters decided that 20% gelatin was too dense to be the best simulant, and 10% is today much more common. (As an aside I have often wondered if that was because the lower density material led to the production of more dramatic expansion cavities, but that’s just speculation.)

I have watched countless videos of bullets being tested in gelatin, and the first thing to keep in mind is that the temporary cavities they produce are just that: temporary, even in that test medium. After the temporary cavity collapses, there are usually permanent signs of the bullet’s effect and which is often (erroneously) referred to as the “permanent cavity”; I say erroneously because most of it is not a cavity at all. In gelatin or similar simulants there will be tearing and sometimes other signs of the material’s being stretched. Those signs usually do not extend to the size of the temporary cavity, and are usually much smaller than the temporary cavity’s.

So, that’s one thing about evaluating the effect’s of a bullet’s passage. The other major factor, though, is that gelatin and similar substitutes are just that: substitutes for real flesh. There is at least one online photo of the effects of an M4 bullet on a man’s upper thigh. When the wound is opened surgically for treatment, it looks huge and horrible. But that’s another difference between that incident and even shooting at dead meat: bleeding into the wound enhanced the visual effects.

Why didn’t you see the “massive” expansion effects that you expected? This is where I must speculate because I’ve seen no even marginally well-documented similar experiments like you conducted. But a couple things to consider.

First and foremost, meat, especially dead meat, is not the same as gelatin or other simulants, or perhaps it would be better to say that they aren’t the same as meat. Gelatin was, as I understand it, first chosen as a simulant in the early Army tests because penetration and the temporary cavities formed by projectile passage mimicked that of living flesh. I don’t plan to reread the entire book, but I don’t recall that the condition of the gelatin after a test and whether it resembled an actual wound was a matter of interest. For post-impact wounds, the book discusses real combat results seen in World War II. The fact your piece of meat didn’t show large cavitation effects doesn’t mean, IMO, that they didn’t occur. Even if the temporary cavitation did cause damage to the tissue at a distance from the wound track, it’s quite possible that a cursory visual examination by someone who isn’t an experienced pathologist might not reveal it.

A possible relevant fact was something way back when certain law enforcement agencies started adopting hollow point bullet loads for their handguns and there was (as always) an initial outcry from antipolice agitators decrying the transition. A very well known forensic pathologist at the time, Dr. Vincent Di Maio, stated that at autopsy he could not see any difference in effects between hollow point handgun bullets and the nonexpanding kind. We know that at similar velocities expanding bullets and something like an FMJ training projectile produce significantly different temporary cavities in tissue simulant, but according to him and even with his training and vast experience with gunshot wounds, their permanent effects in flesh showed no obvious difference. I suspect that’s because flesh can be stretched to a much larger degree without permanent effect.

Keep in mind, too, that bullet velocity has a very large effect on temporary cavitation and permanent results. If, as the above post indicates, the bullet you were using would have been traveling at less than 2000 feet per second, that can make a big difference as well. Back when I read articles about such things, some pundits claimed that there was a velocity threshold of 2000 to 2200 fps before cavitation from passing projectiles caused damage away from the wound track. I’m very skeptical of that claim, but there’s no doubt that the slower the bullet, the less cavitation and therefore the less damage away from the wound track it will cause.

After all that, what can we say? It’s good that you went to the effort of conducting your experiment, but due to many limitations of your test protocol, I wouldn’t draw any firm conclusions about the results. Ultimately, the test of any hunting round will be how it performs in actual practice, or as Jeff Cooper was fond of saying, “The proof of the pudding is in the eating,” i.e., what do we actually see and experience, not what do we expect or assume?

Would feral hogs be a good test medium? My guess is there are probably plenty of search results available for the mentioned calibers etc.

Didn't read the whole thread though, so maybe I'm way off bringing it up.

Not a bad idea, but the results aren't specific enough. It seems plenty of folks use .223/5.56 on hogs; anything from 35gr varmint bullets to 77gr BTHP. There are no anecdotes concerning the Hornady 73gr FTX specifically, however. Also, that's just the starting point, as I am attempting to determine performance potential out of a 10.5" barrel at further distances (lower velocities). My parameters are specific enough that, even if I found a story about hunting hogs with the same bullet, they'd likely be using a longer barrel, at a nearer distance (or some other incorrect combination of factors).

There are some reduced velocity tests. The gel will still be placed a few yards away, but the ammo is downloaded to the point that it is effectively simulating longer ranges. There aren't many of these tests. Of the ones I just watched (one being an actual long range test using M855), bullets like the Sierra 77gr TMK and military M855A1 both did well at reduced velocities; the M855 had such a long "neck" that it would have passed through most targets, before it started to perform. This is the classic 5.56/.223 reduced velocity phenomenon I am wanting to avoid. Most short barrel detractors cite (rightfully so) reduced velocities as their evidence; these reduced velocities have the bullets just zipping through the target, as opposed to expending any energy in them. By using ammunition designed to expand at lower velocities, I hope to gain lethality at longer ranges than generally considered practical with a shorter barrel.

This message has been edited. Last edited by: KSGM,

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claimed that there was a velocity threshold of 2000 to 2200 fps before cavitation

That's one reason I am curious about these, and similar, bullets. Though the target may not be getting the velocity-induced trauma of temporary cavitation, the bullets are supposedly designed to still expand at velocities of 1800fps, or even 1500fps. It blows my mind that the overwhelming majority of gel tests online are performed at point-blank range. When velocity is such an important aspect of performance, why wouldn't we be more curious about where the threshold is? If some sort of threat is within 25 yards of me, I don't reckon I care what kind of bullet I've got, as I can likely achieve multiple hits. When more distance is introduced, the likelihood of multiple hits decreases, so performance of that first, and maybe only, shot matters more. More distance means less velocity. I know I am not shedding light on any mysteries here, it's just annoying that online terminal performance tests in gel are almost all at CQB distance.

quote:

Originally posted by KSGM:
it's just annoying that online terminal performance tests in gel are almost all at CQB distance.

I feel your annoyance about much of what’s posted on the Internet because so often it’s easy to identify things that could be improved. Some things, however, are not so easy. For example, getting good informative hits on typical gelatin blocks at 300 yards would be a challenge for most of the posters when they can’t even ensure the bullets hit the center of a block at 15 yards (or less!).

Reduced velocity reloads would solve the issue for testing purposes.
Not sure why no one has tried that, on youtube anyway, as far as I know.

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Reduced velocity reloads would solve the issue for testing purposes.

There are videos like that; that's what I was referring to, in the second paragraph of my reply to your post.