How Reliably do Modern JHP's Expand?

[SwampDweller]

Folks:

I assume all of my defensive ammunition fired in a confrontation will fail and plan accordingly. If the ammo expands great, but I never count on it. Food for thought.

Bruce

It is my understanding that modern, reliably expanding/penetrating 9mm loadings are what made the caliber cross the threshold from marginal to well-performing, with FMJ having a pretty bad track record in effectiveness, and earlier expanding loads having erratic performance... if we don't take the reliable performance of modern ammunition as a given, doesn't that kind of turn the whole situation on it's head?

[Bruce Cartwright]

It is my understanding that modern, reliably expanding/penetrating 9mm loadings are what made the caliber cross the threshold from marginal to well-performing, with FMJ having a pretty bad track record in effectiveness, and earlier expanding loads having erratic performance... if we don't take the reliable performance of modern ammunition as a given, doesn't that kind of turn the whole situation on it's head?

Swamp Dweller:

I understand that modern 9mm ammunition is miles ahead of where it was 25 years ago. I am aware of the advances in 9mm bullet construction and the increased level of terminal performance. In fact my awareness of the effectiveness of the new 9mm ammunition was partly what motivated me to begin using the 9mm as a duty/carry round nearly a decade ago.

The point I was trying, albeit inartfully, to make goes to mind set. Lots of folks worry about what hollowpoint round is best etc. Thats fine. I tend to focus on prevailing in the fight, knowing that no two fights are the same and that the bad guy always gets a vote. I train for the worst case scenario, rather than the best case scenario. I am aware of several incidents where "good" ammo did not have the desired effect. My solution is to pick a round with documented performance, such as the ones recommended by Pistol Forum's own DocGKR and then train heavily in the event the round does not perform properly. If I am rewarded with a round that performs well, that is icing on the cake. Very few real world fights go "according to plan".

None of the ballistic folks who actually test these rounds will guarantee (at least the ones I have talked to) that any particular round will stop a fight. They told me that better ammo helps me but there are no guarantees. There are too many variables involved, such as size of your opponent, physical health, mindset, training, narcotics use, your ability to accurately place rounds on target and others. The ballistics folks will tell you that modern ammunition "should" be able to do "X" in terms of expansion and penetration. Whether that performance means the subject of your gunfire will stop is another story altogether.

Thank you for the question and the opportunity to clarify my remarks. Let me know if that clarifies things.

Bruce

[Caballoflaco]

It is my understanding that modern, reliably expanding/penetrating 9mm loadings are what made the caliber cross the threshold from marginal to well-performing, with FMJ having a pretty bad track record in effectiveness, and earlier expanding loads having erratic performance... if we don't take the reliable performance of modern ammunition as a given, doesn't that kind of turn the whole situation on it's head?

You’re right man. You’ve figured out that the switch to 9mm is really just a lie made up so women and limp wristed men who prefer the sexual company of other men can pass qual courses at the FBI and Police agencies. I didn’t believe you the first several threads you posted about this, but I think you’re making a much stronger argument now.

I’m selling all my 9’s and moving back to forty and 10mm so I don’t get stuck toting an ineffective caliber that was designed just for shooting prisoners in the back of the head.

[SwampDweller]

Swamp Dweller:

I understand that modern 9mm ammunition is miles ahead of where it was 25 years ago. I am aware of the advances in 9mm bullet construction and the increased level of terminal performance. In fact my awareness of the effectiveness of the new 9mm ammunition was partly what motivated me to begin using the 9mm as a duty/carry round nearly a decade ago.

The point I was trying, albeit inartfully, to make goes to mind set. Lots of folks worry about what hollowpoint round is best etc. Thats fine. I tend to focus on prevailing in the fight, knowing that no two fights are the same and that the bad guy always gets a vote. I train for the worst case scenario, rather than the best case scenario. I am aware of several incidents where "good" ammo did not have the desired effect. My solution is to pick a round with documented performance, such as the ones recommended by Pistol Forum's own DocGKR and then train heavily in the event the round does not perform properly. If I am rewarded with a round that performs well, that is icing on the cake. Very few real world fights go "according to plan".

None of the ballistic folks who actually test these rounds will guarantee (at least the ones I have talked to) that any particular round will stop a fight. They told me that better ammo helps me but there are no guarantees. There are too many variables involved, such as size of your opponent, physical health, mindset, training, narcotics use, your ability to accurately place rounds on target and others. The ballistics folks will tell you that modern ammunition "should" be able to do "X" in terms of expansion and penetration. Whether that performance means the subject of your gunfire will stop is another story altogether.

Thank you for the question and the opportunity to clarify my remarks. Let me know if that clarifies things.

Bruce

Yes sir, that makes absolute sense. Can't really count on anything so make good hits that count on their own. Thank you for the clarification, I concur.

[SwampDweller]

You’re right man. You’ve figured out that the switch to 9mm is really just a lie made up so women and limp wristed men who prefer the sexual company of other men can pass qual courses at the FBI and Police agencies. I didn’t believe you the first several threads you posted about this, but I think you’re making a much stronger argument now.

I’m selling all my 9’s and moving back to forty and 10mm so I don’t get stuck toting an ineffective caliber that was designed just for shooting prisoners in the back of the head.

If that's what I was trying to do, I wouldn't be carrying a 9mm loaded with 124gr +P Gold Dots every day and primarily shooting 9mm pistols. There is no "argument."

[Chuck Whitlock]

I’m curious; when you guys talk about barrier penetration for law-enforcement use, are you guys are talking about being able to shoot through a car door, a wall or something of that nature but still have the bullet not expand until it hits the person, or are you talking about being able to shoot through heavy layers of clothing?

I really don’t have any concerns at all for using the federal HST or the Speer gold dot as my defense ammo but when you look at the Hornady critical defense the Hornady critical duty, isn’t there a reason why at least according to Hornady that the defense is more or less made for people like myself and the critical duty it is made for law enforcement due to the fact that it will penetrate heavy barriers better being that that’s what law enforcement might be the most likely to be faced with?

This might be a dumb question but would the federal HST or the spear gold dot compare better to the Hornady critical duty or critical defense or is there even a comparison as far as hornady’s purpose for each round? I guess if I confused anybody with my question then what I’m trying to ask is if the federal HST was intended to be a lot more of a law enforcement round as opposed to a home defense round, if it even matters.


Sent from my iPhone using Tapatalk

One answer:

https://press.hornady.com/view/id/1410991876

[Velo Dog]

Expansion must never be the basis for bullet selection, but considered a bonus when, and if, it occurs. Bullet selection should be determined based on penetration first, and the unexpanded diameter of the bullet second, as that is all the shooter can reliably expect. "

I think this is missing some context and requires more explanation. While this quote is undeniably true, a lot more reasoning went into selecting a new handgun cartridge.

At the time that was written, the Relative Incapacitation Index (RII) had gained popularity.
9 inches of penetration was believed to be adequate and the Maximum Temporary Cavity was given more significance. The 9mm Silvertip performed well by this measure.
https://www.ojp.gov/ncjrs/virtual-li...fects-volume-1

After the 1986 FBI Miami shootout the Relative Incapacitation Index fell out of favor and greater importance was given to the permanent wound cavity including sufficient penetration of vital organs in the bullet's path.

Although the FBI could have simply chosen a different 9mm bullet such as the 147 gr. Hydra-Shok, it still fell a little short of the desired penetration in the 40-round test which included hard barriers like auto glass and sheet metal.
https://www.americanrifleman.org/con...bi-ammo-tests/

Compared to .45 Auto, the 10mm offered higher magazine capacity and similar performance with hollow points.

Instead of just picking the largest caliber or most powerful load, the Bureau weighed many factors and tried to balance terminal ballistics, accuracy, recoil, ammo capacity, weapon size, etc.

[TexasViking]

Occasionally I re-read the old FBI Handgun Wounding Factors and Effectiveness paper from the late '80s. There was one line in particular that said that hollow point bullets only expand 60-70% of the time at best.

The paper says this:

"Damage to the hollow point by hitting bone, glass, or other intervening
obstacles can prevent expansion. Clothing fibers can wrap the nose of the bullet in a cocoon like manner
and prevent expansion. Insufficient impact velocity caused by short barrels and/or longer range will
prevent expansion, as will simple manufacturing variations. Expansion must never be the basis for bullet
selection, but considered a bonus when, and if, it occurs. Bullet selection should be determined based
on penetration first, and the unexpanded diameter of the bullet second, as that is all the shooter can
reliably expect. "

It made me think, how reliable are hollow points in expansion today? Is there a percentage number that can be ascribed? Considering that the switch back to 9mm was facilitated by the advent of well-designed expanding loads, there must have been a huge increase in the reliability of expansion. Still, everything can fail.

Underpowered ammo certainly didn't help. One reason the .357 Magnum stuck around as long as it did with the TX DPS until they switched to autos for greater firepower, and adopted the closest round they could find. Unfortunately, and largely based on demographic diversity, the DPS was forced to switch to the 9 x 19mm for those who became troopers without any shooting skills. Veteran troopers, however, have freedom of choice with 9 x 19mm, .357 SIG and .45 ACP. And since the Rangers are part of the DPS, Maybe a few of them carry 10mms as well, since they're not limited to the SIG P-320 series.