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  #51  
Old 02-04-2010, 01:15 PM
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First off, many "ammunition failures" have nothing to do with the bullet performance or lack thereof. If you don't hit vital areas, it doesn't matter what you're using-if you rule out tactical nukes.

Secondly, I believe that when Mas Ayoob wrote about a progression from the 147 gr 9mm to .40, he also commented that many of those departments that stayed with lighter weight (+P?) 9mm bullets stayed with the 9. Some departments went back to a lighter weight bullet and decided to stay with the 9mm.

The performance of the 125 gr JHP .357 Magnum load has demonstrated that a light for caliber, high velocity round can be extremely effective. A combination of bullet design and load development can deliver similar results in any other caliber.

Last edited by WR Moore; 02-04-2010 at 01:19 PM.
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  #52  
Old 07-01-2012, 05:43 PM
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My 2 cents.. I am still trying to figure out which is the best load to carry also. One thing I disagree with is the statement that size/weight of the bullet is king. A simple law of physics from high school says that Force F = M (mass) x V2 (velocity squared) Since velocity is squared the faster the projectile can travel the force goes up much faster than using a larger bullet.
I will explain the math using no units.
Force =a mass of 10 and a velocity off 10 = 10x(10x10) = 1000 units
If you double the mass to 20; Force = 20 x(10x10) = 2000 units
But if you double the velocity; Force = 10X (20x20)= 4000 units
So velocity is really king. I am not a ballistics expert or even a good journeyman. I am just looking at the math. SO I don't understand why a lighter bullet (say 115gr) going significantly faster than a subsonic 147gr bullet has less penetration. It should have more. Please help me with this. I must be missing something. Unless when we mean penetration we really mean the damage done by a larger object when it enters a cavity. That is a different science altogether. Somewhere in the past couple of month I read a really interesting paper on stopping power, hydro shock and penetration. I wish I could find it. Anyway.. I remain a learner on this subject and I just carry good factory fresh ammo that is recommended to do the job of ever needed.
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  #53  
Old 07-02-2012, 10:01 AM
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There is a whole lot more to the science of terminal ballistics than just one aspect or focus point. Lots of variables must come together in the successful development of a good performing bullet and then on to loadings for that bullet. There are many published articles and books on terminal ballistics along with a ton of info on the internet. Some is good, some bad, and some written with hidden agendas. Read all you can and form your own opinions.

Velocity alone is not the end all in defensive ammo. From all my study and profession, I have found no scientific evidence that a bullet at handgun velocities can shock the body. A handgun bullet works as a cutting implement that destroys tissue. Bullets that expand, jacketed hollow point, are the most effective duty/defensive bullet designs as they disrupt more tissue resulting in more blood loss to stop an attacker.

A light weight/high velocity JHP may over expand and not reach deap enough into the body's vital organs despite its velocity and kinetic energy. A slower/heavier bullet will have the momentum and mass/sectional density to continue to plow through clothing, bone, muscle, etc and reach the vitals. In the past JHP bullets were highly dependent on being velocity driven to expand. The latest high tech bullet designs are not dependent on velocity to perform. In selecting ammo for serious purposes penetration is tops on my list followed by expansion. If a certain loading has adequate penetration, consistent expansion, accuracy/pistol functioning, and performs well through heavy clothing/light barriers, its velocity is of no real concern to me. Bill
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  #54  
Old 07-02-2012, 10:01 AM
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[QUOTE=38-44HD45;1275847]David, I think some of our "senior" writers like Chuck are sometimes guilty of being frozen in time with respect to advances in bullet design, load efficiency, and the like. Chuck would fit that category. Since I'm something of an old guy, I try not to hold it against them.

I agree,sir. It's a very prevalent thing with those writers who don't keep up with the advances. I can't hold it against Taylor either.He's the only guy I know besides myself who's crazy enough to shoot himself to see if his vest worked.
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  #55  
Old 07-03-2012, 12:11 AM
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Quote:
Originally Posted by mbliss57 View Post
My 2 cents.. I am still trying to figure out which is the best load to carry also. One thing I disagree with is the statement that size/weight of the bullet is king. A simple law of physics from high school says that Force F = M (mass) x V2 (velocity squared) Since velocity is squared the faster the projectile can travel the force goes up much faster than using a larger bullet.
I will explain the math using no units.
Force =a mass of 10 and a velocity off 10 = 10x(10x10) = 1000 units
If you double the mass to 20; Force = 20 x(10x10) = 2000 units
But if you double the velocity; Force = 10X (20x20)= 4000 units
So velocity is really king. I am not a ballistics expert or even a good journeyman. I am just looking at the math. SO I don't understand why a lighter bullet (say 115gr) going significantly faster than a subsonic 147gr bullet has less penetration. It should have more. Please help me with this. I must be missing something. Unless when we mean penetration we really mean the damage done by a larger object when it enters a cavity. That is a different science altogether. Somewhere in the past couple of month I read a really interesting paper on stopping power, hydro shock and penetration. I wish I could find it. Anyway.. I remain a learner on this subject and I just carry good factory fresh ammo that is recommended to do the job of ever needed.
Google "sectional density" for the answer to your question. There is more to the physics than velocity.

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Last edited by Out West; 07-03-2012 at 12:14 AM.
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  #56  
Old 07-03-2012, 02:19 AM
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Mass and momentum are what is being neglected..

For the record Dallas, Tx PD started running 9mm as issued in 1988'ish. They used the 115fgr Hornady XTP and had issues with bullets not expanding (clogging up with clothing) or shallow penetration. They then moved to the Remington +P+ 115gr JHPand the problems persisted. In 1996 they did two things, they authorized the .357sig, and they changed their 9mm duty load to 147gr Winchester Ranger SXT, and later to Ranger Talon. The problems have gone away except for some old cops tales of woe about 9mm.

Contrary to what certain magazine and book writers will tell you, even in the 80's 147gr JHPs did just as well (or poorly) as bulkets in other weights.
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  #57  
Old 07-06-2012, 11:50 AM
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Sorry to say David but you are a bit mistaken on your thinking here. The term over penetration is a valid concearn to the responsable shooter and refers to a shot going completely through your assailant and possibly putting innocents in the area in danger. Defense rounds expand out for two reasons, first to cause extra tissue damage inside your attacker than compared to a FMJ round to better stop them and to stop over penatration so the round isn't as likely to go through your assailant, into a building behind him, through the dry wall and into some poor child. So yes over penetration is something to be worried about.
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Originally Posted by David Sinko View Post
I'll go out on a limb here and say that there is no such thing as "over penetration." The term itself makes it sound like complete penetration of your adversary is a bad thing, from a ballistic point of view. The best way to stop your assailant who is trying to kill you is by shooting THROUGH him. That means that we'd like the bullet to expand at least a little bit and we want one hole in and another hole going out. This belief that a bullet must stay inside the adversary to "dump all its energy" is complete nonsense and is the purvey of gun writers, police chiefs and lawyers. Being concerned about being sued is one thing, but advocating the carry of less than effective ammo for the explicit purpose of not being sued is another matter entirely.

Does this mean that we want to go around carrying ball ammo? No, not at all. In this day and age we have bonded cores (Speer Gold Dot) and homogenous construction (Barnes XPB) which should expand at least a little bit and retain enough weight to punch on through. In my experience, many of our better loadings today simply lack velocity. It's unfortunate that we have some of the best technology and it's being defeated by watered down ammo. From what I've seen out on the street, we're far better served by jacketed flat points than most of the hollow points we have nowadays.

I will concur with the laws of physics and momentum in that all else being equal, heavier is almost always better.

Dave Sinko
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Ammo Thread, 9mm 115 Gr. vs 124 Gr. vs 147 Gr. in Ammunition-Gunsmithing; First off, many "ammunition failures" have nothing to do with the bullet performance or lack thereof. If you don't hit ...
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