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Posted: 12/18/2015 12:47:08 PM EDT
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So I'm relatively new to shooting and have a Colt LE1920, CZ 75B, and Ruger LC9s. I'm very interested in understanding the best rounds for each and what the tradeoffs are.
But I have not yet found a coherent explanation for the selection of different grain bullet weights for a particular gun. For example, in looking at personal defense for a 9mm, most name brands have the exact same bullet in 115gr, 124gr, and 147gr. I've seen the gel tests for each and I can't find much different. If I've settled on a brand - eg, Speer Gold Dot or Federal HST - how should I decide what grain bullet to use? Separately, once I've decided the brand and the bullet weight, how do I decide whether to go with standard pressure or +P? thanks! |
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Some people like fast , light bullets that fragment or disintegrate when they hit flesh-(.i.e., the hyper-velocity 85 gr segmented 9mm zipping along at 1450 fps) vs the heavier 147, slow moving but relatively deep penetrating 9mm version (1000fps). Also, are you shooting thin skinned animals (deer) vs thick muscled, pig, you need a different bullet type (rhinos and cape buffalo get popped with solid copper bullets that really penetrate). So there is weight, speed, bullet design to consider and what kind of targets and barriers there might be. With humans you want good penetration (14-18") and bullet expansion to cause tissue disruption and organ failure, but with pistols the shock value of getting hit is usually not immediately noticed (ie, watch all the videos of people getting shot by a pistol and running away- they could stand right there and return fire, just as easily) unless a CNS shot. So your question needs more parameters, or just pick a 30 caliber rifle and be done with it (with 5.56 and then you got 55 gr vs 62 gr and velocity and tumbling bullets and yadda yadda, yadda again HP vs SP vs FMJ). |
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Any given cartridge has a finite amount of energy available to it, in the form of a powder charge. The bigger the case, the more "energy space" up to the limit of recoil tolerance..
That amount of energy can only accelerate bullets whose weights (masses) lie within a certain a certain range, without developing pressure above the safe limit. Within that range bullets are selected to achieve definite ballistic performance, and to match (among other things) different rifling twists, in the interest of stability (accuracy). This is the broadest, general way I can think of to explain it. |
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9mm wise... I prefer the 124gr, and 147gr's ... which ever shoots more accurately. Top of the line HST , Ranger, and the previous GD style all work... I am not a fan of the G2 Gold Dot.
I use the 147gr +P HST. I prefer the added +P ....not everyone does.... non +P HST's work dang near just as well. ( If not better ) I feel the 115gr lacks enough penetration in general. I am guessing you mean Colt LE6920...if that is the case... the SD bullets in 5.56 / .223 all have different good points v. bad points. I suggest you read....http://www.ar15.com/content/page.html?id=210 A 1n7 twist will pretty much handle everything.... while mathematically it may be "perfect"... in the real world it doesn't mean a heck of a lot. The choices are vast. |
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When it comes to most rounds I prefer middle-heavy weights. 9mm usually the 124, 40 the 180s, 45 the 230s and so on. Basically like stated above, I usually prefer the original style weight the round was made for. But there are advantages to each round, and it also depends heavily on the barrel length of the pistol and what targets you are shooting at. I must say the HST is the best round out there if you ask me. That is just my opinion but from all reviews/research I have done it is ahead of the pack in every way possible. The gold dots are OK, but not close to an HST. It seems the HSTs perform well in every test in every caliber. Most HP type defense rounds will work well in specific calibers and sizes but it isn't common to see one that performs at the top in every test like I see the HST do.
Now when it comes to 5.56 that is a different matter all together, I like velocity over weight. It just isn't a round built for heavy bullets, although some prefer them and I won't run them down it just isn't for me. I prefer the M193 55 grain full power ammo. Now if you have a shorter barrel like say 7.5"-12.5" the M193 may still be OK up close but that is where it is beneficial to have a nice HP round that will still expand with the lower velocity. And also if you plan to shoot longer ranges of say 500+ , that is where the heavier 69-77 grain rounds really shine. |
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Quoted:
So I'm relatively new to shooting and have a Colt LE1920, CZ 75B, and Ruger LC9s. I'm very interested in understanding the best rounds for each and what the tradeoffs are. But I have not yet found a coherent explanation for the selection of different grain bullet weights for a particular gun. For example, in looking at personal defense for a 9mm, most name brands have the exact same bullet in 115gr, 124gr, and 147gr. I've seen the gel tests for each and I can't find much different. If I've settled on a brand - eg, Speer Gold Dot or Federal HST - how should I decide what grain bullet to use? Separately, once I've decided the brand and the bullet weight, how do I decide whether to go with standard pressure or +P? thanks! Stick with standard pressure. +P will be harder on you and your gun for little to no gain. A for bullet weight, that gets stickier, because to a degree, it comes down to personal preference. For your CZ-75B, just shoot whatever you like. I prefer 124 grain. My dad prefers 115 grain. Both of our CZ-75Bs shoot either weight just as good. It's just personal preference at that point. For your LC9, if you're going to carry it for self defense, I'd recommend the 147 grain stuff. Several years ago....many years....maybe even 20 years ago, one of the gun rags did some penetration testing using snub-nosed .38 revolvers and compact 9mms and found that heavier bullets (158 grain and 147 grain respectively) penetrated better than the lighter bullets available for the caliber when fired from a short barrel. As for your Colt, for blasting, shoot whatever's cheapest. For self-defense, that's a whole 'nother can of worms that there have been hundreds of threads on, and I'll just leave that one alone. |
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Pressure; there's a 'standard' pressure for every kind of gun. Normally you never have to worry about what it is if you buy factory ammo. But in a nutshell, the pressure limit is a constant. So with a heavier bullet, velocity has to be lower, because more of the allowable pressure is needed to accelerate it. A lighter bullet can go faster because it's easier to accelerate it. Typically I like heavier bullets, which also means lower velocity. With the 9mm, that would be the 147 gr. With the AR15, it depends on the barrel twist rate. Is your 6920 1:7 or 1:9? It says right on the barrel. For 1:9, use 62 grain. For 1:7 use 69 gr to 77 gr. My Colt 6721 is 1:9 so I have 62 gr for it. I keep 75 gr for the other one which is 1:7 and has a small combat scope.
In reality, it's much more important that you hit what you're aiming at than it is to shoot a bullet of a certain weight. |
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If you are interested in gel comparisons of various hand gun rounds, this may interest you...
http://www.luckygunner.com/labs/self-defense-ammo-ballistic-tests/ |
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All your answers are in this post tacked at the top of the page: http://www.ar15.com/ammo/project/Self_Defense_Ammo_FAQ/index.htm |
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