.45 ACP Accuracy


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azhunter122
November 21, 2008, 10:11 PM
Hello Everyone,

I went out target shooting with my new Kimber Pro Carry II and was shooting 230 GR Aguila ball ammo, the target (bowling pin) was about 40 feet out and I kept shooting high time after time until finally I put some 165 GR Hydoshocks in and it was dead on prcisely accurate! Is there a reason why this came out the way it did and could it just be because it was practice ammo or because it was 230 GR ammo vrs. 165 GR ammo? What grain and bullet would everyone suggest that I try out to decide which is best for self defense and what is most accurate. Please also keep in mind that the bullet MUST NOT overpenetrate. Thanks for the help!

- A new 1911 owner!

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DoubleTapDrew
November 21, 2008, 10:39 PM
Typically heavier bullets will move the point of impact higher because the gun starts recoiling before the bullet clears the muzzle. 230gr is the most popular weight for .45 but shoot what hits closest to point of aim if your sights aren't adjustable. It's a .45, they are all effective :)
Buy a box of all the popular self defense hollowpoints (FMJ will usually penetrate more than HP) such as Speer Gold dot, Federal HST, Winchester SXT, the hydra-shoks you already tried etc and just go with whatever shoots most accurately.

mljdeckard
November 21, 2008, 10:46 PM
One of the reasons I keep a full-sized 1911, is that it was designed to work at a certain bullet weight and velocity. If you shoot 230s through a smaller one, good for you that they work, but remember, they will be going slower than 875 FPS, the speed at which they were designed to work. This is why we have 165s and 185s, to allow for better velocity from shorter barrels. I use HSTs.

Kind of Blued
November 21, 2008, 11:13 PM
A 165 grain .45 caliber projectile will still hurt plenty.

As far as .45 ACP defense loads go, 185gr. bullets are far more common. Remington's Golden Sabers are known to feed very well even in finnicky 1911s and they have a 185gr. load available in both standard pressure as well as +P.

That might be a good starting, or ending point. When I was in the process of choosing carry loads for my 9mm and .38 Spl, I paid a lot of attention to bullet performance. When I started carrying a .45, I suddenly didn't care. As long as it feeds well and IS a hollow point, it'll do the job, even if one out of every 20-30 doesn't expand. I'll do some tests some day to figure out the best load for my 5" gun as well as a 4.25" gun, but for now, just the fact that it's a .45 before it even get's started is a comforting thing.

MaterDei
November 21, 2008, 11:17 PM
Typically heavier bullets will move the point of impact higher because the gun starts recoiling before the bullet clears the muzzle.
I've never heard this before.

MaterDei
November 21, 2008, 11:22 PM
Double Tap

JDGray
November 21, 2008, 11:32 PM
My Ultra carry II shoots higher with my 230gr powder puff loads. My 230gr defense loads, shoot to POA. Guns shoot different weight loads, in different places, find a load your gun likes, and stick with it.

Or you could reload:)

sammy
November 22, 2008, 12:00 AM
Quote:
Typically heavier bullets will move the point of impact higher because the gun starts recoiling before the bullet clears the muzzle.

I've never heard this before.

I have never seen anything to support this. Where are you getting this information? I am curious because I have noticed this myself.

DoubleTapDrew
November 22, 2008, 02:34 AM
https://www.thefiringline.com/forums/showthread.php?t=70984
That's one place that mentions it. I haven't tested it scientifically myself and I didn't get straight As in physics class, but the heavier bullets do seem to have a higher POI in my experiences. If what they are saying is true it should be more pronounced in longer barreled guns. My rifles do it too when I switched from 140gr to 160gr for example.

robctwo
November 22, 2008, 09:36 AM
I reload a bit. I have noticed that with heavier bullets, or less powder the POI seems to be higher. I've heard the slower out of the barrel logic and tend to agree. I have adjustable sights on most of my pistols and will usually do a minor tweak with a new load to center.

Does it make sense that with faster powders I'm shooting lower because the bullet gets out of the barrel at the low point of my flinch?:p

outerlimit
November 22, 2008, 09:43 AM
It seemed counter-intuitive to me as well, but in my experience with heavier grain handgun cartridges, the point of aim is higher as well.

I have also heard this mentioned on guns and ammo tv and an episode of wild west tech on the history channel, where they mentioned that with the heavier 250gr. LC load, gunfighters would aim low at close range, because they knew it would hit high.

It seems the ballistics of the heavier handgun rounds is high up close and then drops more quickly at longer range.

The Bushmaster
November 22, 2008, 10:15 AM
azhunter122. I have a Kimber UCC II. I use Hornady XTP 185 grain bullets and find them to do the job at 870 fps from a 3" barrel.

You might try them...

BlindJustice
November 22, 2008, 12:22 PM
Sheeish, the standard Gov. load was around 830 fps

The delayed unlocking of the 1911 action is predicated
by the pressure developed and the action
starts to unlock andthe slide going rearwards
begins just before the bullet leaves the muzzle
Bullet weight has little to do with this If anyone
argues the point thier understanding of the mechanics
and the physics are faulty as well as it being proven
with a high speed camera.

BlindJustice
November 22, 2008, 12:23 PM
For the O.P. - you might look around and order some 200 gr. 'flavors' for a shorter barreled
1911 variant.

Randall

onebigelf
November 22, 2008, 12:51 PM
I use 185 Golden Sabres in a 4". POIPOA for me. No feed issues at all. It's my backup to the shotgun that is my Something-went-bump-in-the-night gun.

John

jfdavis58
November 22, 2008, 01:27 PM
I'm not here to tell you what ammo to buy. I am telling you to ignore the nonsense about recoil effecting the POI and causing a difference between light and heavy bullets. The reason heavy bullets hit higher is simply ballistic coefficient and momentum. Get a good External Ballistics program (Sierra Infinity 6 for example). Use the bullet library to pick two bullets with matching profiles but different weights and run the calculations. Examine the data and 'see' two things:(1) there is a difference; (2) it's not as much as you might actually observe from an empirical (shooting) test.

rcmodel
November 22, 2008, 01:32 PM
I have never seen anything to support this. Where are you getting this information? I am curious because I have noticed this myself.It's common knowledge if you hang around handguns long enough.

NRA Bullseye Target shooters have two sight settings in their dope book, one for 185 grain wad-cutter, and one for 230 hard-Ball.

Bullet weight can be used to "sight in" fixed sight guns.

When the 200 grain .38 Special "cop load" came out 75 years ago, the cops right away found out thier S&W & Colt revolvers shot way high because they were factory sighted for 158 grain bullets.

If you look at any big-bore Magnum revolver, the front sight is noticably much higher then the rear sight in relation to the bore line. Because the gun is already kicking up off target before the bullet leaves the barrel.

Slow heavy bullets shoot higher then light fast bullets because of bore dwell time & recoil differance.

rcmodel

Z71
November 22, 2008, 01:39 PM
I've found that the .45acp cartridge is accurate enough. But that the guns themselves are not created equal.

Meaning that one .45 will be a so-so shooter and the next quite accurate with the same ammunition.

Steve C
November 22, 2008, 06:56 PM
At 40ft the change in point of impact due to heavier or slower weight bullets should be no more than an inch or two, centrinly not enough to put them off a bowling pin if you're aiming for the center of the big part.

Are you sure you are not breaking your wrist up or healing in anticipation of recoil? Either of those is much more likely to throw shots off a relatively big target.

outerlimit
November 26, 2008, 09:30 AM
ignore the nonsense about recoil effecting the POI and causing a difference between light and heavy bullets. The reason heavy bullets hit higher is simply ballistic coefficient and momentum.

Could you explain this further? Why does momentum and ballistic coefficient cause heavier handgun bullets to hit higher?

MrBorland
November 26, 2008, 09:57 AM
Slow heavy bullets shoot higher then light fast bullets because of bore dwell time & recoil differance.


Personally, I believe it's the latter (recoil) and not the former (dwell time). Momentum must be conserved, and when you solve the conservation of momentum equation for the distance the gun moves while the bullet's still in the barrel, you quickly see that time cancels out, since dwell time is the same amount of time the gun's actually being pushed. In other words, the distance the muzzle moves while the bullet's still in the barrel is dependent on the length of the barrel, and the weights of the gun and bullet (+ powder charge). It should be independent of the muzzle velocity.

Has anyone who reloads noticed - if a 230gr bullet tends to hit high, will that same bullet hit higher or lower if the round is charged a bit hotter or lower? My bet is that more will notice a difference on POI when shooting heavier/lighter bullets rather than a little slower/faster bullet of the same weight.

FoMoGo
November 26, 2008, 10:43 AM
Not a 1911, but I have a S&W M21 .44 special... with fixed sights.
Half moon blade frunt and a "gutter" rear.
With this revolver heavier bullets impact higher unless you drive them hard.
Hot loads recoil harder but have less dwell time in the barrel for the recoil to effect them.
I finally have the load that shoots poa/poi.
if you dont believe that weight and velocity will make that much difference in poi, play with some hand loads and see for yourself.


Jim

nutter
November 26, 2008, 11:43 AM
Could you explain this further? Why does momentum and ballistic coefficient cause heavier handgun bullets to hit higher?


I can't say anything about ballistic coefficient, but momentum is basic physics.

The heavier bullet will have more inertia. Higher inertia (momentum) will cause friction to decelerate the bullet || that much less. Less deceleration will get the bullet to target || that much sooner. Less time for gravity to work on the bullet will cause the POI to be || that much higher.

MifflinKid
November 26, 2008, 12:59 PM
When I shoot a 200gr bullet at 900 fps the POI is always lower than a 240gr bullet also at 900 fps shooting at 20 yards.

Further, for all loads, if I take a firmer grip and lean into the gun, the POI will be lower than if I use my normal grip.
This is an an example of how biomechanics affect the points of impact -- more resistance (more of my body mass resisting the recoil and the tighter grip resisting the muzzle rise) cause the POI to go down.

J. Jay
November 27, 2008, 02:00 AM
I disagree. If the gun started to recoil before the bullet left the barrel, no one would ever hit anything with a pistol. When you change bullet weight, poi moves. When you change powder charge, poi moves. Heck even changing form fmj to hp will move it. Different guns like different ammo. Find what works well for you, and stick with it.

The Bushmaster
November 27, 2008, 09:53 AM
You go J Jay...

outerlimit
November 29, 2008, 08:14 AM
I can't say anything about ballistic coefficient, but momentum is basic physics.

The heavier bullet will have more inertia. Higher inertia (momentum) will cause friction to decelerate the bullet || that much less. Less deceleration will get the bullet to target || that much sooner. Less time for gravity to work on the bullet will cause the POI to be || that much higher.

I've never heard it explained like that before. Interesting..

However a 230gr. bullet will generally be moving slower than a 185gr. one. So the 185gr. bullet would get to the target faster.

I'm still in the camp that thinks it has something to do with more barrel time for the heavier bullet though.

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