Do lighter bullets go low and left??

[Carry_24/7]

I agree that's it's probably a trigger control issue. My Taurus 740 Slim shoots low left "most of the time.". I cannot shoot this pistol accurately on a consistent basis no matter what I do. I actually am more accurate with my LCP. It only serves a a training tool now.

 

[peacefulgary]

Hey, don't argue with me, argue with Speer, Winchester, Remington, and every other ammo maker around the globe.
Heavier bullets hit lower than lighter bullets, all other things being equal.

 

[Olibobwa]

Thanks everyone. All the talk about trigger control made me want to try it again. So...I went by the range with the earphones still in my passenger seat and the 15 or so rounds in my cupholder to try my luck. Loaded up a couple of rounds, thumbed the hammer back, and shot Left Handed. Just as pretty as you please right in the bullseye.

Ended up shooting all of the wwb and a cylander of HP's. When I wasn't flinching they were all hitting mighty close to POA. I was kinda disappointed I was so bad, yet kinda pleased it wasn't my guns...Definitely became more fun when I realized, if I did my part, the gun would do it's, too.

Guess the next move is to do some research on proper grip and how to pull the trigger.

Once again, thanks everybody

 

[Sport45]

Hey, don't argue with me, argue with Speer, Winchester, Remington, and every other ammo maker around the globe.
Heavier bullets hit lower than lighter bullets, all other things being equal.

But all other things are rarely equal. The lighter bullets almost always have a higher velocity which means less time in the barrel. And because they also tend to recoil less the barrel is rising at a slower rate.

So, all things not being equal, lighter bullets tend to strike the target lower than heavier bullets from the same gun at typical handgun distances.

 

[Terminus009]

I shoot left-handed and I notice that when I have been away from the range for a while I ALWAYS shoot low to the left, because I've lost my "trigger feel" and finish the squeeze with a light jerk. Doesn't seem to matter if I'm shooting my DAO .380, my cousin's DA/SA .45, my girlfriend's SA .25 or my friend's Model 10. After the first few shots I see the grouping, say "rats!" to myself, and consciously try to get back into the groove. I don't spend enough time practicing: starving student, food and books before bullets!

But that's just my experience. I have no idea about the ballistics of a light round vs a heavy one.

 

[MrBorland]

Lighter bullets have a tendency to shoot lower on a target than a heavier bullet because the bullet is in the barrel for a shorter period of time.

Mr. Hughes is correct on this. All else being equal, the lighter bullet will hit lower on the target than the heavier bullet no matter the velocity or bullet type.

Eh, not to nit pick, but Sgt Hughes (and others) suggest that the effect is velocity dependent, since it's all about how much time the bullet spends in the barrel.

Personally, I'm on the velocity-independent side of the fence: The forward momentum (mass x distance/time) of the bullet equals the rearward momentum of the gun while the bullet's still in the gun. Time in the barrel is the same as Time the gun's being pushed back, so it cancels out, and the effect is therefore velocity independent.

Solve the rest of the equation, though, and you come to the remarkable conclusion that the relative points of impact, to a first approximation, depend soley on bullet weight (heavier hits higher), gun weight (heavier hits lower), and barrel length (longer hits higher).

(One of these days, I'm going to buy a ransom rest, load up some different loads and actually gather some data. The theory's either right or flat wrong (I'm open to either possibility) and it'll take bona fide data to show which it is.)

Apologies for the thread veer...

 

[Mal H]

I think this is where your theory goes astray:
"Time in the barrel is the same as Time the gun's being pushed back, so it cancels out, and the effect is therefore velocity independent."

While that statement is basically true if the effect you mean is time-in-barrel equals time of recoil. You seem to also be implying that the time-in-barrel factor is a constant for different weight bullets. It's not. The time-in-barrel will be a smidge longer for heavier bullets than for light bullets which gives the recoil factor more time to raise the barrel as the bullet travels inside of it. In other words, the effect we're talking about is indeed velocity dependent. And bullet velocity for normal handgun loadings is most always a function of bullet weight.

 

[Wuchak]

Hey, don't argue with me, argue with Speer, Winchester, Remington, and every other ammo maker around the globe.
Heavier bullets hit lower than lighter bullets, all other things being equal.

You are using bullet drop numbers which are only relevant after the bullet reaches the apex of its flight and begins to descend. The heavier bullet falls faster. At 20 feet the bullet is not falling it is still rising to the apex and it shoots lower for the reasons stated. Even if the different weight bullets were fired from a gun barrel that couldn't rise from recoil the higher velocity of the lighter bullet will cause it to impact lower because it reaches the target at an earlier point in its trajectory than the heavier one.

If you want to have some fun exploring this download the Remington Shoot software for free from Remington's site and look at the trajectory plots of different loads.

 

[MrBorland]

I think this is where your theory goes astray:
"Time in the barrel is the same as Time the gun's being pushed back, so it cancels out, and the effect is therefore velocity independent."


While that statement is basically true if the effect you mean is time-in-barrel equals time of recoil.

The muzzle does continue to rise after the bullet's gone, and the total rise and total timespan is what is usually referred to as "recoil". But it's only a portion of the recoil that moves the bullet up, since the barrel can only move the bullet up while the bullet's still in the barrel. This timespan equals time-in-barrel. The remaining recoil doesn't affect the bullet rise. How can it? The bullet's gone!

You seem to also be implying that the time-in-barrel factor is a constant for different weight bullets. It's not. The time-in-barrel will be a smidge longer for heavier bullets than for light bullets which gives the recoil factor more time to raise the barrel as the bullet travels inside of it.

I'm suggesting that 2 loads using the same bullet but different powder charges will hit the same POI, despite the difference in velocity & time-in-barrel. It's obviously true the faster bullet gets out of the barrel faster - and while the gun recoils with more velocity, the timespan of its recoil while the bullet's still in the barrel, is correspondingly shorter. The distance the muzzle moved the moment the bullet exits the barrel is therefore the same as for the slower bullet of the same mass. Ergo, the POI is time- and velocity-independent - it depends on the bullet/gun mass ratio and barrel length, but not on velocity.

 

[tipoc]

So if we think through it some it works like this:

A handgun will shoot lower on the target with light loads and higher with heavy loads no matter the velocities, all else being equal. As mentioned by others bullet drop is not a factor here because of the close ranges involved. The reason has to do with barrel jump and movement of the gun.

Take your unloaded revolver and stand sideways in front of a mirror and aim at something safe to aim at across the room. Notice that even though you are aiming straight at the object through the sights the muzzle of the gun is pointing downward and below it. The moment the bullet begins to leave the case the gun begins to move upward in recoil. A good amount of this is while the bullet is still in the barrel and moving forward. At a certain point, as the muzzle rises, the bullet will leave the barrel at a point that intersects with the point you were aiming at.

If you are shooting 2 bullets of different weight but at the same velocity the recoil will be heavier for the heavier bullet. With the same velocities the two bullets will reach the muzzle at the same time and will leave the barrel at the same time. But with a heavier kick and jump for the heavier of the two the angle of the barrel will be higher at the time the heavier bullet leaves the barrel compared to the lighter. The impact of the heavier bullet will be higher on the target and the light bullet will strike lower.

If we add some powder to the lighter bullet to increase it's velocity, and also it's recoil by a bit, it will now leave the barrel earlier and at a lower angle as the barrel rises. The lighter bullet will again strike lower on the target.

If we take two bullets of the same weight but at very different velocities (900 fps and 1200 fps for example) the bullets will impact at about the same spot. This is why I can fire a round of 38 Spl. from my M27 and follow it with a round .357 from the same gun and if they are the same weight bullet the point of impact will be very close. A change in bullet weight though will change the point of impact regardless of velocity.

The factors involved here are the weight of the heavier bullet which increases muzzle jump and so the angle the bullet leaves the barrel, and the amount of time the bullet is in the barrel. These combine to effect where the bullet strikes the target, the heavier higher and the lighter lower.

Gen. Julian Hatcher looked into this many years back and Robert Rinker explains it well in his book "Understanding Firearms Ballistics". You can see it for yourself as well with some experimentation.

I suppose a fella could cook up some handload that split the difference some where a light and heavy bullet hit about the same, and in some particular guns the difference may be minor. But in general what has been said is true.

tipoc

 

[James K]

The "recoil is not a factor" folks should perform one simple test. Take any fixed sight revolver and lay a straight edge from the rear sight to the front. If that line is parallel to the barrel, recoil does not affect where the bullet goes.

So why does the barrel time not affect a rifle? Why do ballistic tables for rifles show that bullets drop?

First, all bullets drop and begin to do so the instant they come out of the barrel. The bullet will NEVER go above the bore line of the barrel at exit time. And rifles are affected by barrel time. The difference is that rifles are much heavier in relation to bullet weight than handguns, so the recoil movement is less and its effect on the bullet is less. But yes, rifle barrel time and recoil does affect the bullet strike in relation to the point of aim.

But at longer ranges, the effects of gravity and air resistance on the bullet become much more important than the effect of recoil on the bullet while it is still in the barrel.

Jim
Jim

 

[MrBorland]

So why does the barrel time not affect a rifle?

It does. As I explained above, simple physics says the issue becomes bigger as barrel length increases as well, so you'd expect rifles to be affected. Below is something I grabbed from Lilja Barrels' website. I'm guessing they know a thing or 2 about rifle precision.

From: http://www.riflebarrels.com/articles/50calibre/lengths_velocity_50_bmg.htm

...we looked at how barrel stiffness decreases with length, and as a result potential accuracy possibly degrades too. Also, the amount the rifle recoils while the bullet is still in the barrel increases. This can lead to poorer accuracy, because it becomes more difficult to consistently shoot the rifle with greater recoil movement.

Edit: Forgot to add that while a rifle barrel may be several times longer than a handgun barrel, a rifle is also several times heavier, so rifles are probably in the same ballpark as handguns. Maybe better, as rifles generally shoot lighter bullets, so their bullet-to-gun mass ratio is lower.

 

[KyJim]

The heavier bullet falls faster.

No. It falls at the same rate. Except for air resistance, a feather would fall just as fast as a lead ball. The heavier bullet is usually not traveling as fast so it doesn't go downrange as far before it hits the ground. But it is actually falling at the same rate.

BTW, the bullet's shape will play into it's trajectory, the more aerodynamic the less air friction will slow it down. More of a factor in rifles than handguns.

 

[Wuchak]

No. It falls at the same rate. Except for air resistance, a feather would fall just as fast as a lead ball. The heavier bullet is usually not traveling as fast so it doesn't go downrange as far before it hits the ground. But it is actually falling at the same rate.

If we lived in a vacuum you'd be correct but since we don't you cannot simply say "except for air resistance" since there is in fact air resistance here in the real world outside of a lab. The heavier bullet is going to be larger which means it is going to have more air resistance so no, they are not falling at the same rate. It's a small difference but it's a difference.

 

[KyJim]

The heavier bullet is going to be larger which means it is going to have more air resistance so no, they are not falling at the same rate. It's a small difference but it's a difference.

You make unfounded assumptions. First, there are such things as steel and copper bullets. "Larger" and "heavier" are not synonymous. More important to this discussion, nobody considers how fast a bullet drops from a stationary release. What we do consider is how the shape of the bullet effects it's velocity as it travels downrange. This, in turn, tells us about the trajectory of a bullet.

My point was and is that it is a gross and inaccurate generalization to say that a heavier bullet falls faster than a lighter bullet. It's simply not true.

 

[Wuchak]

....My point was and is that it is a gross and inaccurate generalization to say that a heavier bullet falls faster than a lighter bullet. It's simply not true.

Please provide some published load data that shows where bullets of similar design loaded to full potential have the lighter bullet dropping faster than the heavier one. Since my statement is so inaccurate you should have no trouble doing this.

By falling faster I do not mean how long it takes to hit the ground from the time it leaves the barrel. I'm talking about trajectory. After the apex the point of impact at each distance will be lower for the heavier bullet than the lighter bullet. This is due to the heavier bullet moving slower and simply covering less horizontal distance for each drop in height. It is lower at each distance than the lighter bullet hence it has fallen faster even though the total flight time might be the same.

 

[JohnKSa]

The distance the muzzle moved the moment the bullet exits the barrel is therefore the same as for the slower bullet of the same mass.

I worked up a simulation awhile back when this question came up and as nearly as I can tell two identical bullets with different velocities from the same gun will result in the muzzle being elevated identical amounts at bullet exit.

I'm suggesting that 2 loads using the same bullet but different powder charges will hit the same POI, despite the difference in velocity & time-in-barrel.

The fact that the muzzle is elevated at the same angle due to recoil, does not mean that the two bullets will impact on the target in the same place. That's because there are other issues that affect bullet impact point. Muzzle angle at bullet exit is not enough to provide the whole picture by itself.

Besides muzzle angle at bullet exit, you also have to take time of flight into account. And there's another contributing factor as well.

The recoil also imparts an upwards velocity to the muzzle. In other words, the muzzle is not only pointed upwards at bullet exit, it is also moving upwards. The heavier load makes the muzzle move upward at a faster velocity. Therefore it imparts not only a more arced trajectory by virtue of being pointed upward, the actual upward velocity of the muzzle also imparts an upward velocity on the bullet.

In the case of identical bullets fired at different velocities from the same gun, the bullet traveling faster will hit higher on the target for two reasons. It has less chance to fall while traveling to the target and it was also "slung" upwards faster by the faster muzzle rise at the point of bullet exit.

It's not a lot of difference though for practical cases. For example, running the simulation on a 115gr 9mm bullet from a typical polymer full-sized handgun with 1200fps and 1000fps muzzle velocities yields about .7" of POI difference on the target at 25yards.

 

[KyJim]

By falling faster I do not mean how long it takes to hit the ground from the time it leaves the barrel. I'm talking about trajectory.

But that's my whole point. They fall at the same rate. It has absolutely nothing to do with trajectory. It's the force of gravity. That was always my point. It's called standard gravity or standard acceleration due to free fall. The rate is approximately 32 ft./sec/sec or 9.8 m/sec/sec. http://en.wikipedia.org/wiki/Standard_gravity; and http://www.physicsclassroom.com/class/1dkin/u1l5b.cfm