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Old October 2, 2005, 08:37 PM   #1
StL Bill
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9mm grain count....please explain

Hi,
I am the proud owner of a new CZ75 Retro.
I've fired one full 16 mag of 115 grain FMJ to try it out.
It ain't the .45 that I shot in the military..if my memory serves, but seems quite powerful.

My question is related to the ammo I expect to use.
I will use 115 grain FMJ for practice....it's cheap.
I have purchases some 146 grain JHP for defense loads.
Why shouldn't I use 115 grain JHP for that use? Since my need (probably never exist) is intruders in the night, will the extra charge make that much difference?

Please explain the rationale...the practical rationale for spending 50% per hundred....and thanks for your help!!!
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Old October 2, 2005, 08:47 PM   #2
Toney
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fmj might shoot clean through your house
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Old October 2, 2005, 08:58 PM   #3
StL Bill
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Yeah FMJ is for target...the question was...

Why not 115 grain Hollow Point instead of 146 or more?
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Old October 2, 2005, 09:02 PM   #4
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Quote:
Why shouldn't I use 115 grain JHP for that use? Since my need (probably never exist) is intruders in the night, will the extra charge make that much difference?
It's not an extra charge but rather the weight of the projectile.
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Old October 2, 2005, 09:11 PM   #5
StL Bill
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Ok that makes me totally ignorant

But the basic question still stands.
Why the extra 50% in price for a 'heavier projectile'....does it make that much difference?
And, what it +P+ ?
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Old October 2, 2005, 10:07 PM   #6
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Grains are a measure of weight, used both to measure the weight of bullets and powder charges.

It's very rare for an ammunition manufacturer to advertise the powder weight, so it's safe to assume that the grain numbers refer to the bullet weight when you're buying commercial ammo.

The common bullet weights in 9mm are 115gr, 124gr, and 147gr. Generally speaking, in a given caliber, a heavier bullet will penetrate more deeply while the lighter bullet may expand a bit more and will have higher velocity.

The cost differential was not specifically related to the bullet weight, it was related to the higher quality and performance of the ammunition. It's very likely that a 115gr premium hollowpoint defense loading would cost much the same.

Premium self-defense ammo tends to be a good bit more expensive than FMJ training ammo for several reasons.

1. A misfire or jam at the range while practicing doesn't threaten your life. The extra QA that goes into making sure that doesn't happen with your defense ammo isn't free.
2. It costs money to develop a premium expanding defense round.
3. It costs more to manufacture a premium expanding defense round.
4. Self-defense ammo may employ more expensive components such as nickel plated cases or low-flash powder.

+P and +P+ refer to higher pressure than normal.

9mm is limited to 35,000psi peak pressure.
9mm +P is limited to 38,500psi peak pressure.
9mm +P+ does not have industry established pressure limits.

Generally speaking, increasing the pressure increases the velocity and probably also increases the terminal effect of the bullet although it's not clear to what extent. It also results in more recoil and will accelerate wear on the firearm although most people don't have the money to wear out a firearm by shooting +P ammo in it.
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Old October 2, 2005, 10:41 PM   #7
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Make a compromise and load it with 124 gr. +P hollowpoints from any good company.

I use Remington Golden Saber and Black Hills in my Glock 19 and have not had a problem.

If you want to use a lighter bullet, I have used Corbon 115 gr. + P and they seem to be good as well, but I still like the mid-weight bullets.

Home defense ammo is always a bit pricey, but I am sure it would be worth every penny if it needed to be used. Just get good ammo from any good company and test it out and find what you like and what your gun likes.

Stay safe.
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Old October 3, 2005, 07:02 AM   #8
caz223
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147 JHPs PENETRATE more.
They just do.
That can be good or bad, just make sure it's what you want.
Be sure of your target and what's beyond it.
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Old October 3, 2005, 07:35 AM   #9
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Most 9mm's are calibrated for 124gn, at least according to my owners manuals. Although I have not seen a difference in shot placement between them and 115gn fmj target ammo. Try all three and see what shoots best out of your gun. For defense, no matter what you choose, stick with HP.
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Old October 3, 2005, 07:47 AM   #10
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Isn't the 147 grain more suited for a suppressed weapon? Not saying that it wouldn't work but I load my 9mm with Corbon DPX.
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Old October 3, 2005, 11:24 AM   #11
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Suppressed

As in silenced?

If you are going that route, I am not sure. The Can is the Man.

Harley
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Old October 3, 2005, 11:42 AM   #12
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If memory serves me right, the 147 grain was originally developed for use in silenced weapons such as the MP5 (not the MP5SD*.) 147 grain ammo is almost subsonic and creates less of a crack, making it much quieter than 115 grain, while still having the ability to travel and penetrate because of its high weight.

I've carried 147 grain fed. hydrashocks, they shot 100% reliable out of my glock 19, I just recently went down to 135 grain ones because they are more abundant now. I always have this fear of a big bad ape or likewise human being the one to attack me, with 3 inch thick pectoral and ab muscles to penetrate. But that is just one guys fears, not a doctrine of any sort.

(* The MP5SD's barrel/silencer assembly bleed gas pressure as it travels down the barrel turning basically any round into a subsonic round)
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Old October 3, 2005, 12:30 PM   #13
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Like JohnSKa said the grains (115, 124, 147) is bullet weight, nit powder charge.

You don’t really have to use 147 instead of 115, but 147gr bullet does have better penetration despite the lower velocity. btw 135 hydra-shoks are quite effective too…
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Old October 3, 2005, 12:52 PM   #14
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Actually, the 115gr JHP Fedaral 9BP or the 9BPLE (the +p+ version) is an excellent defensive round, it is very reliable and accurate for me. I think a good 115gr JHP in 9mm is a great choice. Many of you say 147gr has better penetration, but I heard that 147gr can underpenetrate. Just goes to show we all hear different things from different sources. 124gr is probably a good compromise. But, shot placement is what matters more that the grain of the bullet.
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Old October 3, 2005, 01:46 PM   #15
281 Quad Cam
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The reason for hearing different things about penetration between 115 and 147, is the way in which it is used. You may hear a story from a seal who shot a guy at 65 yards with an MP5, and you may hear a story from a cop who shot an attacker with a Sig at less than 1 yard.

I dont pretend to know which performs better for which, I sure hope someone who actually knows can speak up. Maybe 115or147 penetrates further at 50 yards.... Maybe the other penetrates further at 2 yards.
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Old October 3, 2005, 01:54 PM   #16
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The heavier weight, although not as flat shooting maintains its momentum at longer ranges better. The formula for bullet momentum is bullet weight in grains x velocity in fps divided by 7000 to get the weight of the bullet in pounds. You will see that the heavier bullets carry much more momentum at the longer ranges and even the shorter ranges for that matter. They even tend to be accurate as they are longer.
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Old October 3, 2005, 03:19 PM   #17
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cje1980

Yes, good and to the point. Not the hollow point, nor the fmj point, but the point you are making.
The recoil sometimes is a little more, allowing your pistol to function correctly all the time.
Unless you are a limp wristed shooter, not to be confused with the other limp wrist's. Then it will probably still not function in the manner it is supposed to.

Harley
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Old October 3, 2005, 11:01 PM   #18
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147's as a rule will penetrate deeper than the lighter weights within the same line of ammo. That means Speer 147 vs. Speer 124. There are SOME 124's that outpenetrate SOME 147's, but that is generally an exception.

This applies downrange as well. Since expansion is dependent on velocity, the faster bullet will expand more. 124's fly faster and expand more than 147's. They have less sectional density to begin with. They will penetrate less than the slower, lesser expanding, greater sectional density 147's.

Finally, understand that just because it has a hollowoint does not mean it will expand. There are numerous documented instances where hollow point bullets failed to expand causing excessive penetration. Thus, we must assume for argument's sake, that hollow point bullets are only LIKELY to expand, and we cannot always count on it.
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