do JHP's ever expand?

M

Mozart

Inactive
I wanted to test my Bersa 380. So I loaded it with Fed. personal defense 90 grain hydra-shoks. I fired it from 21 feet at a pallet stuffed with fiberglass insulation then covered with half-inch plywood on the back. I expected at least some expansion on exit but there was none. Perhaps I don't understand the principle behind jhp's. Why wasn't there any expansion?

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"We know that the Lord is always on the side of the right. My concern is that I and this nation should be on the Lord's side." Abraham Lincoln
 
Generally JHPs don't expand well in a solid medium (which is what compressed fiberglass and wood are). For that, soft lead is probably still the best.

A couple of "on the cheap" home mediums might be a bundle of newspapers that have soaked in your kiddy pool for a few days. Or a couple of gallon paper or plastic milk jugs full of jello.

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Jim Fox
 
A box of dry sand is a good and easy test for expansion. If neighbors aren't too close it can be used in the basement. Four or five inches of sand is enough.

Jim
 
Someone needs to check my facts here, but:

What causes a hollowpoint buller to expand is liquid entering the cavity, and forcing the walls of the cavity open.

If the medium that you're firing into doesn't have any liquid in it, then you won't get any expansion.

LawDog
 
As someone kindly taught me on TFL not long ago, the "hydra" in Hydra-Shok implies a "fluid-type media" is required (or highly desirable) to achieve expansion. This makes sense when you think about it; a more dense media (like wood, for example) will naturally constrain the opening of the projectile, due to its greater strength/rigidity.
 
I was watching CMT's roadtrip show the other day, and they were in the FBI's ballistics testing lab. Exactly what that has to do with country music I have no idea. Anyway, they fired a shot, don't remember what caliber, into balistic gelatin and got around 12" of penetration and good expansion. The same gun and load fired into the gel faced with 1/4" of plywood went all the way through 2 blocks of gel, and had no expansion at all. The plywood plugged the hollowpoint, and kept it from expanding. If you want to test JHPs for expansion, you have to shoot them into a liquid medium.
Eric

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Formerly Puddle Pirate.
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Having had a discussion with bullet designer extraordinare Tom Burczynski about his hollow point designes (Hydra-Shok, Starfire & Quik-Shok) he tried to explain Hydro & Nutonian Physics to this Jarhead.

From what little I gathered HPs rely on channeled hydrolic pressure to cause expansion. There are a few ways to do this (as witnessed by his and others different designes). But the bottom line is that there must be a fluid (or semi-fluid) enviroment to cause the "mechanics" to work correctly.

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Schmit
GySgt, USMC(Ret)
NRA Life, Lodge 1201-UOSSS
"Si vis Pacem Para Bellum"
 
my own observations of gunshot victims as an X-ray tech in the emergency room and O.R. of a level one trauma center and doing follow ups in the morgue of DOA's and those that do not survive has shown me less than 45% of any type of hollow point expands in the textbook fashion in an actual human. that covers the rounds we recovered. a lot were thru and thru and i could not tell you about those. humans are not blocks of gelatin nor are they the same size, density, fat/muscle ratio, ect. this is the reason i put very little reliance on "wonder bullets". as general Patton once said "The best plan is one in which you win even if everything goes wrong."

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Liberty is a well armed lamb contesting the outcome of the vote.
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FWIW, while I agree that JHP's certainly do not expand 100%, it has been my observation in extracting them from perp', er patients, and viewing radiographs while resuscitating these patients that many hp's do expand. The bigger problem in the lighter faster bullets has been expansion followed by fragmentation. While I have no firm numbers, in operating/evaluating on these cases over the last 10 or 12 yrs I would say that QUALITY JHPs (when I'm able to get this info from LEO/perp/homeowner) actually do expand better than 3/4's of the time when they hit somewhere on the torso. Limb wounds are a different story and the results far more spotty.
I actually just removed probably the best expanded bullet I've ever seen 2 days ago; 110grJHP Winchester .357 shot through the buttocks and into the abdombinal cavity which I removed during the operation and measured at just shy of .75" and was completely intact.
YMMV as this is quite obviously not a scientific study. I can say anecdotally, though, I've seen more people killed with .22 shots to head or heart than all other calibers combined. As someone above noted there is no wonder bullet and shot placement still will always win over the lightest/fastest/coolest/blackest/goldest/or heaviest round.
 
If you'd like to consider getting some ordinance gelatin for your tests, see my post [Link to invalid post].

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Gun Tests noticed the plugging phenomenon some years ago. They first plugged the hollow points with cotton, and soon switched to modeling clay as it provided an even greater challenge.

Quality hollowpoints expand, even when plugged.

Walt
 
Several years back, I shot a couple boxes of Speer 200 hp into a hardwood tree, from a full size Mark IV Series 70 Gov't model.

About half expanded. The rest were plugged with wood.

Not bad considering the medium.
 
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