View Full Version : Defensive shooting question.

May 2, 2002, 10:38 AM
Okay, I have a question regarding using 9mm jhp (124gr - I think) inside a home. I have my Kahr K9 Elite loaded with Golden Sabre (124gr - I think) and I am comfortable using and shooting this round and gun. My question falls into the after the BG is shot...will the bullet still be travelling fast enough with enough energy to do damage BEHIND him.

Let's ASSUME that I have 100& accuracy in a HD shooting situation and I hit this BG with a triple tap and he hits the ground like a sack... Wil the 3 rounds that went into him still have enough velocity to travel through him and through any walls behind him (like into my daughters bedroom?)

The most likely shooting range inside my house in a HD scenario would be 7-10 yards with the potential of shooting TOWARDS an occupied bedroom. Now, like I said before, the shooting accuracy is assumed 100% for this question. Will I shoot that well in a real life case...Lord I pray that I do.

Will the jhp expand enough to stop in the wall behind this guy or will it still be travelling fast enough after 7 yards of air time and 12" of body mass/head shot to continue through the next wall and enter the bedroom?

Just a thought and a question. Would a slower moving bullet (lighter grains) be better for this situation? Obviously there are alternate rounds that are options, but let's assume that I only have 9mm for HD.


May 2, 2002, 11:39 AM
Given a good solid hit to center of mass, I don't thimk you will find a 9mm round ( hollow point ) that will go all the way through a person. How ever, I think one must always count on over penetration, as you could miss, or if not you might just hit an arm, or other thin part of the body, and it will go all the way through. Another thought is it probably is not going to come out going in exactly the same direction either.
As far as bullet weight, generally a lighter bullet will be going faster than a heavier bullet. However it will normaly have less penetration than a heavier one.
As for expansion, that can be a very unreliable thing. If he is wearing a heavy jacket, the hollow point can plug up with cloth, and now you have a round nose bullet, which is going to penetrate further now than it would have. In my IMHO expanding bullets are a great thing to have, but one should not count on them to do what they are designed to do 100% of the time. Here it comes down to good old fashioned shot placement.

Just my $.2 worth. :)

May 2, 2002, 12:29 PM
It's dark, the target is moving, people are yelling and screaming, you just woke up, and you may be shot (why does everyone think they are going to get in a gunfight but they will be the only ones shooting), and you assume 100%?

Rule #4 always applies. No matter what you use, .22lr to the .223 of the GSC or buckshot. Just because you have a gun does not mean you get to spray lead everywhere. You MUST presuppose that the round will not be stopped--"know your target AND what is behind it."

May 2, 2002, 12:37 PM
Thanks for the input. That is the info I am looking for.

This is NOT a shoot/don't shoot question. It is not an accuracy question. It is not a question of how calm, cool and collected one might be.

It IS a question of BALLISTICS and ballistics only. This is my question...

Will the 9mm 124jhp round that has just travelled 7 yards and has entered the intruder continue THROUGH him and through the next wall?

I know that there are variables that are unkown such as how big the guy is, and what kind of clothing and what kind of wall. I am NOT trying to make this difficult!

Please advise on the BALLISTICS of the matter...not your opinions of how viable the situation is and the situation and stipulations I have placed on out "scenario in question.

May 2, 2002, 01:30 PM
Depends on the angle at which the bullet entered and exited. That is something you cannot control. Unless the bad guy is willing to honor your request of not moving while you take a shot at him. Remember, the bullet has to travel 7 yards, to the bad guy, go through the bad guy's clothes, go through the bad guy's skin, go through 12 inches of bad guy tissue and muscles, and then have to go through the bad guy's back skin (which is like going through 4 inches of tissue and muscles). If it hits bone, the bullet will deflect in ways unexpected. If it doesn't, then, it will hopefully be deformed enough that it has a tough time getting through the back skin.

If it gets through, it still needs to go through 2 layers of sheetrock. Like KSFreeman says 'know your target AND what is behind it'. If the bad guy has a gun or a knife and is coming at me, and his background is my daughter's bedroom, I could always shift a little bit to the left or right and shoot at the bad guy. Nothing says you have you stay at that position.

May 2, 2002, 02:50 PM
The only thing predictable about bullets are that they are unpredictable.

You might fire one that performs beautifully--full expansion, mostly straight path with maybe a small tumble, stops inside the target.
Your next round might get plugged on cloth and behave justlike hardball.

If terminal ballistics are a concern, then I might suggest a small test. It will be a bit pricey, but it ought to satisfy your concerns. Maybe a few friends will chip in to make it worth your while.

Buy the absolute biggest bone-in ham you can get, and encase it in the fabric or clothes of your choice. Preferably, make it a piece of clothing, with all the seams and buttons and zippers in the right places.

Set it on a sturdy table or other support at 7 yards. Use one or two rounds of your chosen ammunition, take careful aim, and kill the ham.

Then, lay the ham down, and with a sharp knife (and wearing work gloves) bisect the ham on the axis of the entry hole. Note penetration, performance, attitude of the bullet, and all other factors.

To better observe terminal ballistics, you might want to have a video camera set and running on a tripod next to the ham. Be careful not to commit videocide. For this approach, simply hang the cloth or garment, and leave the ham visible on the other side. Of course, shoot with the camera running. Afterward, run the video in slow motion. This will give you an idea of the temporary stretch cavity as you will see the ham expand as the bullet works inside.

To take it even further, you can orient the ham so that the bone is center mass. Mark its location on the outside, with a coresponding bullseye. Carefully fire the round from a rest into the bullseye, and afterward, note the performance of the bullet on bone.

Not too scientific, but the best thing I can think of. If you're on a budget, you can use jello for the medium. Just make sure it is fully set.

Also, set your camera back a bit. It will splatter nicely when hit.

May 2, 2002, 03:02 PM
I think you will find the info you need at


International Wound Ballistics Association

May 2, 2002, 03:15 PM
As wise man in Tejas saith, "bullets are like medicine; they don't always work [as intended]." My point being is that you assume that the round, whatever superadvanced, tactical, practical, neon/xeon bullet you have, will penetrate (or miss) the target. Then act accordingly.

Vern Brink
May 3, 2002, 06:15 AM
Based on the scenario as you have outlined it - I think it is possible if not probable that the round will pass through your BG.

Exactly what will happen after that is anyone's "guess". Wound ballistics are a strange animal - half art, half science. :)

If you have the opportunity, try to get with your local sheriff, state trooper, or large metropolitan LE agency. Someone in your area might be conducting an annual or regular gelatin shoot. Find a test round as close to yours as possible and see how it performs. The info is out there to make your own ballistic gelatin and test your home defense load. It's a lot of effort - how curious are you?

Christopher II
May 3, 2002, 08:33 AM
Will the 9mm 124jhp round that has just travelled 7 yards and has entered the intruder continue THROUGH him and through the next wall? Assume that it will, and plan accordingly.

- Chris

May 3, 2002, 09:15 AM
One tactic would be to drop to one knee so you can angle your shots upward. Even if you find out all the data...you still might miss so all the wound channel data in the world won't matter then. The short answer to you question is: Yes, assume it will penetrate through the BG, wall, and if you don't use sound tactics, your family.

May 3, 2002, 09:36 AM
Ronin raised good suggestion for some.

I don't run, I don't walk much unaided. I can drop.

So if I am going to defend myself, I am going to have to stay in place and try to be the best of the party. I drill some from one or both knee things.

Ham.........sometimes fresh pork roast is a bunch cheaper than ham. Water content often nearer to live flesh also........but fluid content of beef or ham is not truly like living flesh.

Test target......put couple pieces of drywall behind, with space between them. Gives more of an idea of what the ones that go through can do.

Original question.....as above, the number of variables is variable. Results very unpredictable.


CZ Gunner
May 3, 2002, 11:28 AM
Too many variables. Here are a few obvious ones ...

Where did you hit him,
Did the bullet hit any bone,
What type of bullet (grain, composition, etc.),
What distance,
What was the BG wearing (T-shirt or coat),
Where did bullet hit wall,
Did it hit stud, etc.
Did you miss everything,

George Hill
May 3, 2002, 11:59 AM
When in doubt in a case such as this...
If possible, just before firing, drop to one knee. This changes the angle of the bullet's trajectory and any miss or over penetration will go up into the ceiling behind the bad guy instead of through to possible occupied areas.

Double Naught Spy
May 3, 2002, 05:56 PM
Okay, moving from the hypothetical best case scenario situation where you are a perfect shot and land all three rounds in the chest, solid, and the guy drops to KSFreeman's perspective which is probably a lot closer to reality, although maybe still generous to assume you hit the guy with all three shots. There is a much greater likelihood that you will NOT land all three rounds as intended.

If you watch "blood and gore" show on TLC that is all about hospital emergency rooms, you will get a chance to see a fair amount of ballistic wounds in various places on the body. If the guy you shoot isn't too beefy for full of table muscle and your round does not strike something solid, there is a fair chance a 9 mm will pass through such as well a shot below the rib cage. Say, for example, that your intruder was a 6'2" 150 lb crack head. Your 9 mm round will have a hard time finding 12" of body mass to penetrate if you shoot him in the chest straight on. Through and neck, arm, or leg is quite easy for a 9 mm to do, apparently, so long as the round does not hit bone.

At the opposite end of the scale, you could find yourself up against Goliath who weighs in at 350+ and is 5'2" tall. His natural ballistic gelatin may provide enough buffering and cushion to not penetrate to any critical organs.

If you were to shoot a normal-sized person in the chest as you described, the bullet may still exit. The big question would be whether it still had sufficent energy to harm a bystander such as one of your children. Between the body and a couple of thickness of dry wall, chances are that most of the bullet's energy should be spent such that your kids would not likely suffer a penetrating wound.

The only problem with that concept is that bullets tend to not play the percentages sometimes. Some guy may suffer 6 shots and walk himself into an emergency room but one of those shots through a thin area manages to kill some kid on a bicycle 3 blocks away.

May 3, 2002, 11:22 PM
I could set up a test to find out (under the perfect conditions you described). fireing from 7 yards away at a block of gelatin roughly the thinkness of the average human torso with a double thinknes of drywall 7 yards behind the block with another gleatin block behind the drywall, shoud give a pretty good indication. Like the other posters have said...bullet performance can vary greatly, but a properly set up and calibrated ordnance gelatin test would yeild pretty accurate results.

As always, testing is at cost for all TFl members. I donate the labor and equipment, just help cover the cost of gelatin.