115 gr. or 147 gr?

9134 Views 66 Replies 27 Participants Last post by Tarzan1888, Aug 27, 2008

Dustin WJ

Discussion Starter · Feb 22, 2008

My gun is a 9mm and I'm trying to decide which ammo to carry for self defense. I've been shooting 115 gr. target rounds down at the range and yesterday I found some 115 gr. jacketed hollow points. Does anyone know if that has enough stopping power for self defense? Or should I buy the 147 gr. rounds? Thanks in advance.

Dustin

41 - 60 of 67 Posts

ranger45

· #41 · Aug 17, 2008

It used to thought that lighter bullet would expand better/more reliably especially when fired out of a short barreled gun. Heavier bullets often would not open up because they were not moving fast enough. But with newer more modern bullet designs, it seems that bullet conctruction may be at least as if not more important whan weight when it it comes to expansion/ and penetration. This test has some pretty cool pics, etc.

L'attente said:
Do a test like this...

Water Jug Tests

He tests everything from 100gr to the 147gr Federal HST, I would assume the water jugs are substitutes for gelatin and 2 of them match the density of going through a body (I have nothing to back this up).

Here's one of the images

Look at #7 - it's that 147gr and it's purdy, but there are a few that flower out nice and big that aren't 147gr (like 3,5,6,11). But read the test it's pretty interesting.

Tarzan1888

· #42 · Aug 18, 2008

xRapidDavex said:
me = :noob:

What makes a smaller load better? This defies logic IMO. Please elaborate!

The most important factor is shot placement....so if you can't control or manage the recoil of the larger load, then, for you, the smaller load would be better.

There are also many who worry about over penetration.

I discount this because in a gun fight most shots miss and I contend that the ones that miss are more lethal than the ones that may go clear through the bad guy and then go on down field.

Tarzan

SLC-Vegan

· #43 · Aug 18, 2008

Tarzan1888 said:
There are also many who worry about over penetration.

I discount this because in a gun fight most shots miss and I contend that the ones that miss are more lethal than the ones that may go clear through the bad guy and then go on down field.

Tarzan

I live in a house that is very close to my neighbors' houses. I don't want a bullet to go through my wall and theirs, then through a neighbor. For this reason I don't ever load FMJs when I am at home. I shoot a .45 Colt, but even with this large (and slow) round, hollowpoints won't penetrate a wall. 410bore #7 shot definitely won't kill a neighbor, nor will 000 buckshot.
This is the only scenario where I worry about over-penetration.

xRapidDavex

· #44 · Aug 18, 2008

Tarzan1888 said:
xRapidDavex said:

me = :noob:

What makes a smaller load better? This defies logic IMO. Please elaborate!

Click to expand...

The most important factor is shot placement....so if you can't control or manage the recoil of the larger load, then, for you, the smaller load would be better.

There are also many who worry about over penetration.

I discount this because in a gun fight most shots miss and I contend that the ones that miss are more lethal than the ones that may go clear through the bad guy and then go on down field.

Tarzan

That didn't answer my question at all.

Tarzan1888

· #45 · Aug 18, 2008

SLC-Vegan said:
Tarzan1888 said:

There are also many who worry about over penetration.

I discount this because in a gun fight most shots miss and I contend that the ones that miss are more lethal than the ones that may go clear through the bad guy and then go on down field.

Tarzan

Click to expand...

I live in a house that is very close to my neighbors' houses. I don't want a bullet to go through my wall and theirs, then through a neighbor. For this reason I don't ever load FMJs when I am at home. I shoot a .45 Colt, but even with this large (and slow) round, hollowpoints won't penetrate a wall. 410bore #7 shot definitely won't kill a neighbor, nor will 000 buckshot.
This is the only scenario where I worry about over-penetration.

That I understand. I load my personal defense handguns with JHP's and my shotgun with 00 Buck.

I was referring more to those who would chose a smaller gun or loading, that might not penetrate deep enough to stop a threat, because they were worrying that it might go through the bad guy.

In a gunfight there is always potential for collateral damage, but it is only a possibility, where the threat that causes you to draw your weapon is not potential but real.

People who are in apartments or who share a wall with a neighbor, must take additional precautions.

That goes along with rule # 4 Know your target and what is behind it.

Tarzan

SLC-Vegan

· #46 · Aug 18, 2008

Tarzan1888 said:
Know your target and what is behind it.
Tarzan

+1,000,000,000

G

· #47 · Aug 24, 2008

or 124 or other weight.. I shoot 147s and 158s with my suppressor. I prefer hot 115s for the greater energy, I subscribe to the energy theory. That said pick a good hollow point and put it in the right spot repeatedly as fast as you can with any defensive (I leave out .44 mags and up) hand gun caliber and you will well. Ever think why sub machine guns shoot so fast and hold so many rounds? Other wise you have a pistol with a sock :dunno: at that point get a real gun.

Handguns are a compromise.

I think I was Jim Wilson who was at a formal function wearing his side arm and a woman asked:

Why bring that thing here are you are you expecting trouble?

No Ma'am if I expected trouble I'd have brought a rifle and some deputies. (paraphrased)

kalobg

· #48 · Aug 24, 2008

SLC-Vegan said:
I shoot a .45 Colt, but even with this large (and slow) round, hollowpoints won't penetrate a wall. 410bore #7 shot definitely won't kill a neighbor, nor will 000 buckshot.

I will have to disagree with you about hollow points not penetrating a wall.

Hollow points are designed to expand--just like typical loads are designed to go bang. Yet some hollow points fail to expand completely or at all the same way some loads don't go bang. I personally have recovered bullets (.40 S&W and .45 ACP, neither .45 Colt but close enough,) that did NOT expand upon impact and specifically on sheet rock (I believe they were normal Winchester WB HP and my buddy's HST's.)

The edges of hollow points are typically fairly sharp/pointy and the bullet by nature spins, creating a certain amount of drilling action without significant compression to the projectile. Therefore, if the channel of the hollow point fills with material before significant compression is applied to the bullet, it may not expand; see: wallboard, layers of fabric, and denim jackets--(not many people wear denim jackets, but I'm certainly discussing the minority of load issues as well....)

I concur in the fact that placement of rounds and available ammunition is most likely key to stopping a threat. Yet I carry a Sig .45 ACP, I believe I practice enough to be able to place them.

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divegeek

· #49 · Aug 24, 2008

xRapidDavex said:
me = :noob:

What makes a smaller load better? This defies logic IMO. Please elaborate!

If you're looking at two rounds in the same caliber but with different bullet weights, there are so many factors that will affect relative performance that it's hard to make any kind of generalizations.

I won't let that stop me.

All else equal, lighter bullets will have higher muzzle velocities and will typically carry greater kinetic energy (not sure why they do; from the physics of the situation I would think that heavier slugs should pick up more energy during the traverse down the short barrel, but the measured numbers say otherwise). Greater kinetic energy may, in some circumstances, provide greater hydrostatic shock, particularly since the lighter bullets tend to shed their energy faster in the target. Greater velocity and kinetic energy may also improve expansion.

On the other hand, lighter bullets often have lower momentum, which results in a little less penetration. Of course all of the quality self-defense ammo for 9mm and up has decent penetration, but in some circumstances it might make a difference. Also, heavier bullets are harder to deflect which may make a difference, sometimes.

So which is better? Depends on what's in the bullet's path. How much difference can it make? Probably not much. It seems likely that for unobstructed center-mass shots, a faster, more energetic bullet may be slightly better than a slower, less energetic bullet in the same caliber, but the difference is going to be small.

Personally, I'm carrying 135 gr Gold Dot's in my XD9 because I got a good price on them at the gun show.

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G

· #50 · Aug 24, 2008

swillden said:
xRapidDavex said:

me = :noob:
:agree:
So which is better? Depends on what's in the bullet's path. How much difference can it make? Probably not much. It seems likely that for unobstructed center-mass shots, a faster, more energetic bullet may be slightly better than a slower, less energetic bullet in the same caliber, but the difference is going to be small.

Personally, I'm carrying 135 gr Gold Dot's in my XD9 because I got a good price on them at the gun show.

Click to expand...

:agree:

#1 have a gun
#2 know how to use it very well
#3 hit your target till it stops being a threat

#? some other far less important # buy the latest greatest super hallow point of the month. Read Marshals and Shannows book do a whole lot of research (especially on the internet) consider your self an expert on balistics and neglect your shooting skils

Tarzan1888

· #51 · Aug 25, 2008

There are two general trends of thought.

Big and slow or small and fast.

For example a 230 grain bullet traveling at 800 fps has a KE measurement of 5311
While a 115 grain bullet traveling at 1200 fps has a KE measurement of 5960

Edge to the light fast bullet....BUT

A 230 grain bullet traveling at 800 fps has a momentum measurement of 39.8
And a 115 grain bullet traveling at 1200 fps has a momentum measurement of 29.8

Edge the big slow bullet.

Thus the debate begins.

Chose a gun you like with a load that you can handle and shoot well.

Be happy with your choice as you can find statistics to back it up.

The real key is, if you punch enough holes in the right place in a threat, it will fall down and stop being a threat.

Tarzan

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burninator

· #52 · Aug 26, 2008

swillden said:
All else equal, lighter bullets will have higher muzzle velocities and will typically carry greater kinetic energy (not sure why they do; from the physics of the situation I would think that heavier slugs should pick up more energy during the traverse down the short barrel, but the measured numbers say otherwise). Greater kinetic energy may, in some circumstances, provide greater hydrostatic shock, particularly since the lighter bullets tend to shed their energy faster in the target. Greater velocity and kinetic energy may also improve expansion.

Let me start this by saying IANAP (I am not a physicist), but I do play one on TV! The equation for kinetic energy is (.5)*(mass)*(velocity^2), so while a reduced mass will reduce the kinetic energy some, increased velocity has a greater effect (being squared) and can increase the net kinetic energy. A less-massive bullet would also, in theory, be easier to spin via rifling in the barrel leading to less energy lost in this process as well.

--Geoff

divegeek

· #53 · Aug 26, 2008

burninator said:
Let me start this by saying IANAP (I am not a physicist), but I do play one on TV! The equation for kinetic energy is (.5)*(mass)*(velocity^2), so while a reduced mass will reduce the kinetic energy some, increased velocity has a greater effect (being squared) and can increase the net kinetic energy. A less-massive bullet would also, in theory, be easier to spin via rifling in the barrel leading to less energy lost in this process as well.

In general, if you apply the same force over the same distance to two objects with different masses (ignoring friction), their resulting kinetic energy will be identical, but their velocities will be different. So, if the expanding gases pushing the bullet provided a nice, constant force, and friction down the barrel were the same, the light and heavy bullets would have the same kinetic energy.

The faster bullet would also be spinning faster, which means that a greater portion of the energy is invested in rotational kinetic energy, which isn't measured by a chronometer, since it only sees forward velocity, not rotation. That should tend to make the lighter, faster bullet appear to carry less kinetic energy, not more.

However, you pointed out something I hadn't considered. Assuming they're made of the same materials, and since they're obviously the same diameter, the heavier slug must be longer than the lighter one, which increases the surface area to engage the rifling and increases friction. That friction scrubs off some kinetic energy and converts it to heat in the barrel, and a longer slug will lose more.

I don't know that the increased friction loss is enough to explain the energy difference, though. I think instead it's because the force from the expanding gases isn't a uniform, constant push down the length of the barrel. It's a fluid dynamics problem, and there are all kinds of complexities in the way the gas and bullet interact. Something in there, probably having to do with the fact that the heavier slug spends more time traversing the barrel. Maybe the gas pressure falls off more before the slug gets to the end of the barrel? Dunno. Barrel length also plays a role here, as does any loss of gas pressure from the chamber, leakage around the slug, the recoil action of the gun, etc. There are lots of factors and you'd need to be a better physicist than me to know what makes the difference.

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G

· #54 · Aug 26, 2008

I think he was trying to point out that the inertial mass would take less energy to put in to motion along the rotational axises which is probably more than offset by the increased rotational velocity. The semantics of internal ballistics concern me far less than my group size

Paul

· #55 · Aug 26, 2008

Tarzan1888 said:
There are two general trends of thought.

Big and slow or small and fast.

For example a 230 grain bullet traveling at 800 fps has a KE measurement of 5311
While a 115 grain bullet traveling at 1200 fps has a KE measurement of 5960

Edge to the light fast bullet....BUT

A 230 grain bullet traveling at 800 fps has a momentum measurement of 39.8
And a 115 grain bullet traveling at 1200 fps has a momentum measurement of 29.8

Edge the big slow bullet.

Thus the debate begins.

:agree: This is why I don't participate in these discussions. EDIT: (except this post I guess....durrrrr)

Like others have said, find a gun you like, find one you can shoot well, AND most importantly, carry it with you everywhere, and always. Oh yeah, put bullets in the gun. LOL. Then hit what you are aiming at. I personally don't give a lick what someone carries. I wouldn't want to get shot with any caliber bullet of any weight.

G

· #56 · Aug 26, 2008

PW said:
:agree: This is why I don't participate in these discussions. EDIT: (except this post I guess....durrrrr)

Like others have said, find a gun you like, find one you can shoot well, AND most importantly, carry it with you everywhere, and always. Oh yeah, put bullets in the gun. LOL. Then hit what you are aiming at. I personally don't give a lick what someone carries. I wouldn't want to get shot with any caliber bullet of any weight.

Check I got the ammo and this is how HK loads its guns

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divegeek

· #57 · Aug 26, 2008

hedonistic said:
I think he was trying to point out that the inertial mass would take less energy to put in to motion along the rotational axises which is probably more than offset by the increased rotational velocity.

Doh! You're right that I ignored the fact that a lighter mass will take less energy to get up to speed. Not sure how I missed that one

You're also right that the effect would probably be offset by the increased rotational velocity. I'd have to think about how to calculate which effect would dominate; it's not clear to me.

hedonistic said:
The semantics of internal ballistics concern me far less than my group size

No argument here.

althor

· #58 · Aug 26, 2008

swillden said:
hedonistic said:

I think he was trying to point out that the inertial mass would take less energy to put in to motion along the rotational axises which is probably more than offset by the increased rotational velocity.

Click to expand...

Doh! You're right that I ignored the fact that a lighter mass will take less energy to get up to speed. Not sure how I missed that one

You're also right that the effect would probably be offset by the increased rotational velocity. I'd have to think about how to calculate which effect would dominate; it's not clear to me.

Well, rotational energy isn't much. I worked up the numbers for a 124gr. 9mm at 1100 fps from a 1:9 twist barrel and I get < 2.55 foot-pounds... (I used a cylinder for the shape of the projectile, so the actual rotational energy would be less.)

The difference in Tarzan's example is about 41 foot-pounds. I haven't calculated the difference in rotational energy between the two examples he gives, but its going to be much less than the number I came up with in my example.

KE(rotational) = 1/2*I*w^2, where I is the moment of inertia and w is the angular momentum.

(As always, I could be up in the night.)

G

· #59 · Aug 26, 2008

Here is how important I consider the wight of a handgun projectile I carry a Kahr P9 originally bought for my wife where recoil was more of a concern. I wouldn't spend the money to switch to a .40 in the same platform. I have gone from Double Tap 115+p to federals 124 grain HST reason? I no longer trust my old ammo after finding a 147grain bullet in the 115s! Speer's 124grain short barrel load, corbon's loads and the rest of the premium ammo is just to expensive to shoot and rotate 19.00 for 50 rounds of the federal lets me establish reliability at a reasonable cost. Sure the super tactical octopus fanged super shredder load from Joe's tactical ammo has impressive advertising and can shoot the crud out of jello but, at close to or over $1 a bullet I cant afford to shoot enough to test the ammo gun compatibility. Unless there's some exploding uranium ammo its still a handgun! don't expect "one shot stops" unicorns, gnomes, and other fairy tale's to come true.

CR500AF

· #60 · Aug 26, 2008

We may as well be all packing S&W 500's if we are all so concerned. :nilly:

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