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147 grain requires adjustment in POA? Login/Join 
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I'm not very knowledgeable about ammo nuances and such. I try to shoot all different grains just to see how well I can shoot various ammo types. Shot 115, 124, and 147 grain 9 mm today out of my new P210A and trusty CZ Tactical Sport. I've shot 147 before but never noticed any difference in my performance. Today however, shooting American Eagle 147, impacts were all consistantly high, very high in fact, no matter what distance, 7 feet, 15, and 25. I've shot various manufactures before, again of all dofferent grains, but haven't noticed this phenomenon before. Is this typical or my imagination?
 
Posts: 17 | Registered: November 14, 2017Reply With QuoteReport This Post
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Typically a heavy, slow bullet will hit higher on the target than a light, fast bullet. Look at the box of AE 147's and see if they put performance data on it, and if that load is slower than the other 147's you've used.

Were your groups as tight as usual with this brand, or larger than you're used to seeing?


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Every normal man must be tempted, at times, to spit on his hands, hoist the black flag, and begin slitting throats.
-- H L Mencken
 
Posts: 7222 | Location: Illinois farm country | Registered: November 15, 2008Reply With QuoteReport This Post
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quote:
Originally posted by newtoSig765:
Typically a heavy, slow bullet will hit higher on the target than a light, fast bullet. Look at the box of AE 147's and see if they put performance data on it, and if that load is slower than the other 147's you've used.

Were your groups as tight as usual with this brand, or larger than you're used to seeing?


Tight is relative, lol! But, yes, my groups were consistent with my normal shooting abilities.

And, I really appreaciate the first part of your response. I learned something I was completely ignorant about. I've been shooting only recreationally for years. Always thought the higher the grain, the more forceful the shot would be, meaning higher grain, faster velocity. I now see that's not the case. Thank you for that clarification.

By the way, the performance data is on the box. But, never paid attention one way or the other previously, with any brand. Guess, I have some reading to do.
 
Posts: 17 | Registered: November 14, 2017Reply With QuoteReport This Post
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This actually begs another question. If one 9mm round is heavier and slower than another, what's the advantage of a heavier round? I think I've just been wasting money target practicing with 124 and 147 :-(
 
Posts: 17 | Registered: November 14, 2017Reply With QuoteReport This Post
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I know Winchester and Speer both have performance data on their websites, and I imagine most of the rest do, as well. Check there for data to compare with your AE rounds.

As to your new question, the idea is to impart momentum to the object you're shooting at, if it's a self-defense or hunting application, expressed as Energy. The manufacturers' data will usually include Muzzle Energy as well as Energy at various distances, which will give a good indicator of performance.

The basic formula is Energy=Mass times Velocity Squared, E=MV2 on my primitive keyboard. As a lighter weight (lower Mass) will accelerate more quickly than a heavier weight (higher Mass), theoretically it's easier to generate more Energy by pushing a light bullet faster. On the other hand, though, that lighter bullet will also lose velocity more quickly than the heavier bullet, meaning it doesn't necessarily put as much Energy into the target, the key being "necessarily." It's a fine balance, best determined by observed performance.

My personal preference, based on the difficulty in obtaining observed performance, is to favor heavier bullets, but that trend is not as valid now as it was in the past. A good example is the .40S&W round, which shows dramatically increased performance as you go from the standard 180gr bullet to the 155gr bullet. And the best observed performance these days seems to be with the 125gr bullet in the .357SIG round. In the Good Old Days, the 230gr .45ACP was king.

Other factors to consider are penetration and wear on the weapon. When you understand the concept of Mass, you'll see that it leads to greater penetration, a bad thing in a crowd when your round traverses an assailant and hits an uninvolved party behind him. On the other hand, at least in .40S&W, the greater energy of the 155gr rounds has caused noticeably greater wear on pistols, shortening their lifetime.

If you like the 147gr 9mm round, check into the new FBI load by Speer. I don't spend much time thinking about 9mm, but the FBI did, and I would imagine its performance should be adequate for self-defense, even out to fairly extended ranges.

Hope this helps.


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Every normal man must be tempted, at times, to spit on his hands, hoist the black flag, and begin slitting throats.
-- H L Mencken
 
Posts: 7222 | Location: Illinois farm country | Registered: November 15, 2008Reply With QuoteReport This Post
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Yes, it helps greatly! Still gonna start learning more about the subject, but appreciate you taking the time for the thorough reply! Thank you sir!
 
Posts: 17 | Registered: November 14, 2017Reply With QuoteReport This Post
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A 210 I once had liked 147 grain bullets. It was consistently more accurate with that bullet.
 
Posts: 139 | Registered: February 07, 2009Reply With QuoteReport This Post
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A lot has been written over the years that I've been in the sport, but off the top of my head I can't think of any one good book on the subject. It's something most of us just learn on our own, which to me is the great thing about it.


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Every normal man must be tempted, at times, to spit on his hands, hoist the black flag, and begin slitting throats.
-- H L Mencken
 
Posts: 7222 | Location: Illinois farm country | Registered: November 15, 2008Reply With QuoteReport This Post
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quote:
Originally posted by MagiaNera:
Today however, shooting American Eagle 147, impacts were all consistantly high, very high in fact, no matter what distance, 7 feet, 15, and 25. I've shot various manufactures before, again of all dofferent grains, but haven't noticed this phenomenon before. Is this typical or my imagination?

Define "high". If it's 2" at 7 ft, you may have been just having a STD.
(Shitty Trigger Day)

15, 25 yds maybe, but 7 ft? No, I've never personally seen a change at just over 2 yards.


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After the game, the King and the pawn go into the same box.
 
Posts: 2342 | Location: AZ - West side of the valley | Registered: October 26, 2006Reply With QuoteReport This Post
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It's all interior ballistics. The heavier the bullet, the slower it is (all else being equal), meaning it's in the barrel longer on travel. That means it will exit the muzzle later in the recoil cycle, i.e. when the muzzle is angling higher. So not your imagination or technique.

It seems counter-intuitive at first, but really it makes sense. A heavier bullet will impact higher, and a lighter bullet lower.
 
Posts: 10427 | Location: SF Bay Area | Registered: December 11, 2003Reply With QuoteReport This Post
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I haven't looked at this issue in a long time (decades, maybe?) but I believe this was true for pistols but not rifles, which is why I didn't mention it in my first post.

If I remember correctly, the reason was that rifles are typically sighted in for a distance greater than the apex of the bullet's flight, but pistols are set for a lesser distance, the distinction being the practical distance of engaging a target.


--------------------------
Every normal man must be tempted, at times, to spit on his hands, hoist the black flag, and begin slitting throats.
-- H L Mencken
 
Posts: 7222 | Location: Illinois farm country | Registered: November 15, 2008Reply With QuoteReport This Post
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quote:
Originally posted by MagiaNera:
Today however, shooting American Eagle 147, impacts were all consistantly high, very high in fact, no matter what distance, 7 feet, 15, and 25. I've shot various manufactures before, again of all dofferent grains, but haven't noticed this phenomenon before. Is this typical or my imagination?


How 'hard' was your hold on the gun? I ask because I had the same thing happen to me. My
P239 shot 6" high at 20' compared to my other groupings with 124/115 grain ammo. I realized I was not holding the pistol tightly, and that was allowing excessive muzzle climb with the heavier 147 grain rounds.


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Posts: 5428 | Location: Newyorkistan | Registered: March 28, 2007Reply With QuoteReport This Post
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I've never seen much difference except in a Kahr P9. That pistol was noticeably higher with 147 gr.


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Posts: 5270 | Location: BPensacola, Florida | Registered: September 28, 2009Reply With QuoteReport This Post
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