[RaymondMillbrae]

Hey foks,

sorry if this is in the wrong category, but I couldn't figure-out where to ask this question. (I saw shotgun technique, I saw rifle technique...but no 1911/pistol technique catergories).

I've noticed that when shooting farther targets with my 1911, that I tend to hold my POA (point of aim) a few inches higher than normal. (Like when shooting 3" x 5" plates at 25 yards, or when having to take a head shot at 25 yards when there is a hostage target in the foreground).

This got me to thinking...as the bullet is still shooting completely flat at up to 150 yards, with no drop in it's trajectory.

So I am wondering, "WHY"?

Is it just me, or is there some "technical thingy" going on with my eyes and the sights of the weapon that I am not aware of?

Why do I have a tendency of holding over an inch or two at those distances, and still hitting my POA?

Just curious to hear your thoughts.

Thanks.

In Christ: Raymond

[Sam]

Hi, Raymond! When I shoot my 1911 in .45acp the bullet drops like a lead weight at 150 yards. (wait, it is a lead weight)

There is a nice ballistic calculator at handloads.com that you can use to determine bullet drop for any given load. I use Sierra Infinity 6.0, but there are several good ones on line.

It's no illusion, most carry guns calibers have trajectories like a slingshot at 150 yards.

[RaymondMillbrae]

Thanks, Sam.

But I was referring, specifically, to my precision shots taken at 25 to 50 yard - where the bullets should not be dropping yet.

Why do I aim a few inches higher, yet still hit my POA?

Is there something going on with my sights, or my eyes (brain), that I am not aware of?

In Christ: Raymond

[G-ManBart]

RaymondMillbrae, on Nov 19 2009, 09:08 PM, said:

Thanks, Sam.

But I was referring, specifically, to my precision shots taken at 25 to 50 yard - where the bullets should not be dropping yet.

Why do I aim a few inches higher, yet still hit my POA?

Is there something going on with my sights, or my eyes (brain), that I am not aware of?

In Christ: Raymond

Uh.....cause it's actually dropping! It really depends a lot on the exact bullet, velocity, zero distance etc, but the bullet is dropping from the second it leaves the bore. The only reason they don't hit the ground closer to us is that the bullet is launched starting pointing up....but it still starts falling from that initial boreline the second it leaves the muzzle.

For a typical .40 that's zero'd at 25yds (talking our normal Major loads with heavy bullets going a bit on the slow side) they're going to drop an inch or more at 50yds. If you're talking .45 it's going to drop a fair amount more....slower, worse ballistic coefficient etc, and if you're talking a 9 or Super it'll drop a bit less. R,

[calishootr]

+1 to what Bart said, they are dropping as they leavethe comfy confines ofthe barrel, higher initial velocity will translate into minimal drop at distance, also where you sight you pistol in has a lot to do with it

back in the day(92' western states to be exact) we shot 50 yard standards, using a .45 at the old 175 PF, my hold was in the upper A/B area and i was astonished to seethe result, I had 'managed' to hitthe target in the lower C/D zone a drop of a full 18 inches from point of ain...

fast forward to owning a 38 super where lighter bullet weight and a velocity of at least double that ofthe .45, the same yardage you can aim without any holdover for drop because at 50 yrds the drop for that caliber is minimal at best...as I put it forthe super, point an shoot out to 50 yrds

[RaymondMillbrae]

Thanks, guys.

I've been doing a lot of meditating on this topic, and I have come to a few conclusions:



1) The bullet WILL shoot flat for a specific distance before gravity gets a hold on it and causes it to start falling.

Gravity is always working...but I believe the weight (mass) of the bullet, plus the energy from the pressure pushing it out of the barrel, and the momentum/speed of the bullet, will negate the pull of gravity for a short distance. But after a said distance (too many factors to say specifically when), the laws of gravity will take a hold of it, and start to cause it to slow down and drop pretty drastically. Especially a .45 ACP.

2) The sights on a 1911 pistol are not EXACTLY perpendicular (in liine) with the barrel itself.

The sights are usually zeroed for a specific distance like 20 or 25 yards. So when we are looking through the sights at the center of the 25-yard target, the barrel may actually be slightlky tilted upward to ensure the bullets trajectory will land it at the 25-yard bullseye. But if the sights are zeroed for a closer distance, the bullet will hit low on the 25-yard target. This has everythhing to do with the sights.

3) For the weight (mass) of a .45 ACP round, and the speed we shoot it at for USPSA matches...the bullets will not travel as far as I though before it succumbs to gravity and starts to drop.



Bottom line, the bullet will start to drop...but only after a certain distance. And the zero of the sights will determine how much you will have to hold-over (if you even need to hold-over) for a specific shot.

Great points, yall.

I have a few things I would like to verify the next time I go out and shoot a few rounds.

This information should help me out on those smaller steel plates at farther distances.

Thanks again!!

In Christ: Raymond

This post has been edited by RaymondMillbrae: 20 November 2009 - 07:56 AM

[Singlestack]

RaymondMillbrae, on Nov 20 2009, 09:50 AM, said:

Thanks, guys.

I've been doing a lot of meditating on this topic, and I have come to a few conclusions:



1) The bullet WILL shoot flat for a specific distance before gravity gets a hold on it and causes it to start falling.

Gravity is always working...but I believe the weight (mass) of the bullet, plus the energy from the pressure pushing it out of the barrel, and the momentum/speed of the bullet, will negate the pull of gravity for a short distance. But after a said distance (too many factors to say specifically when), the laws of gravity will take a hold of it, and start to cause it to slow down and drop pretty drastically. Especially a .45 ACP.

Not true. The bullet starts dropping the instant it leaves the barrel.

[LPatterson]

Raymond, one way to prove or disprove your theory of shooting flat for 150 yards is to zero your gun at 50 yards so the bullet is close to the top of its arc and then shoot at 100 yards and see where it hits. With your theory of it shooting flat the bullet might be hitting high since it is only 2/3 of hte way in your flat section. Until you have proven to yourself what we have tried to tell you we can not change your mind. Just use a BIG target so you can see where the hits are.

[RaymondMillbrae]

Hey guys,

don't get me wrong, as I do want to learn. But are you telling me that (let's say) at 2" feet from the barrel, the .45 ACP bullet has already started to drop?

The bullets mass is traveling at maximum velocity as it JUUUUUST leaves the barrel. And are you saying that this velocity/mass/energy will not cancel-out the gravity factor for a few feet...or even a few inches?

Let's say you have a .338 Lapua Magnum. Are you telling me that the mass/velocity/energy of the bullet is not cancelling-out gravity for a small distance?

The very moment it leaves the barrel, huh?!

I am Grasshopper, and you are Sensei. Please explain this to me so I can understand it.

Pease edu-ma-cate me.

In Christ: Raymond

PS: I did not come to the conclusion that the .45 ACP bullet shoots flat for 150 yards...or even 25 yards. But I do believe that it shoots flat for a certain distance (whether it be 5 feet, or even a few inches), unless I am shown the error of my theory. But you have to explain it to me, as I am not one to blindly believe without some facts to support your position.

This post has been edited by RaymondMillbrae: 20 November 2009 - 08:58 AM

[rvb]

better wording might be that gravity has no force opposing it the instant it leaves the barrel. By true definition it may not "drop" but may be rising at first since that's where it's pointed... slightly up. A way I usually explain to people is to hold a coin in my hand. If I just drop the coin, it's obvious it falls straight down. If I toss it an inch in the air before if falls, it's apparent that it's near (within an inch or two) the plane of my hand longer before dropping fast. This is what a bullet does. This is what "flat" means.... it means over a distance (faster is farther) it will be close to the line of sights. The faster the bullet and lower the angle of launch the "flatter" the bullet will appear. But no projectile truely travels "flat" unless it's travelling fast enough it's rate of fall equals the curve of the earth (ie satellites in orbit). To do otherwise would defy physics.

google "projectile motion" for gobs of reading. the parabolic curve from teh accelleration of gravity describes the path of the bullet (minus are resistance, which only slows the bullet and scrunches the far side of the curve).

-rvb

[P.Pres]

230gr 45@800fps sighted in at 50yd

Range Velocity Impact Drop ToF Energy Drift
0 / 800 / -0.5 / 0 / 0 327 0
10/ 793 / 0.72 / 0.35 / 0.04 321 0.45
20 / 787/ 1.39 / 1.26 / 0.08 316 0.53
30/ 781 / 1.5 / 2.72 / 0.12 312 0.66
40 / 776 / 1.04 / 4.76 // 0.15 308 0.83
50 / 770 / 0 /7.37 0. / 19 303 1.06
60 / 764 / -1.63 / 10.58 / 0.23 298 1.33
70 / 759 / -3.86 / 14.38 / 0.27 294 1.66
80 / 753 / -6.68 / 18.78 / 0.31 290 2.03
90/ 748 / -10.13 / 23.8 / 0.35 286 2.45
100 / 742 / -14.19 / 29.44 / 0.39 281 2.92

You could also be slightly flinching, pushing against the recoil ever so slightly, which would show up
progressively with distance further compounding the low shots. Sandbag the pistol at different distances
to eliminate "yourself" from the equation ..

This post has been edited by P.Pres: 20 November 2009 - 09:03 AM

[rvb]

RaymondMillbrae, on Nov 20 2009, 10:49 AM, said:

don't get me wrong, as I do want to learn. But are you telling me that (let's say) at 2" feet from the barrel, the .45 ACP bullet has already started to drop?

cancel-out the gravity factor for a few feet...or even a few inches?

Let's say you have a .338 Lapua Magnum. Are you telling me that the mass/velocity/energy of the bullet is not cancelling-out gravity for a small distance?

The very moment it leaves the barrel, huh?!

Very very basic physics stuff here. gravity is ALWAYS working. The only reason it doesn't fall IN the gun is the gun has a force equal and opposite of gravity to hold it up. gravity is not cancelled out just because something is going fast.

As I tried to clear up in my last post, gravity IS working, but the bullet may not be dropping. if your sights are over the bore, the the bore must be aimed up for the two paths to cross (the two are NOT parallel). So just like tossing a coin a couple inches out of your hand, the bullet/coin is rising, but will peak then fall. Always on that parabolic curve. bullets do NOT travel in a straight line any more than throwing a baseball.

-rvb

This post has been edited by rvb: 20 November 2009 - 08:58 AM

[Singlestack]

Bullets do not "fly". They have no "lift".

If you were to hold your barrel parallel with the ground and fire a bullet, it would hit the ground at the same time as a bullet dropped from the same height.

The sights on your pistol/rifle cause you to point the barrel up slightly.

[P.Pres]

I just thought about this, Mythbusters just did this a couple of weeks ago,
"A bullet dropped and a bullet fired" , I cany remember exactly the distance but
they used a .45 and it hit the ground at 150yds. fired from 3ft off the ground. Then
they had .45 bullet dropped b y a robot arm from the same distance and released at
the exact time and guess what happened ?? They both hit the ground at the same time !!

[bbbean]

P.Pres, on Nov 20 2009, 10:01 AM, said:

I just thought about this, Mythbusters just did this a couple of weeks ago,
"A bullet dropped and a bullet fired" , I cany remember exactly the distance but
they used a .45 and it hit the ground at 150yds. fired from 3ft off the ground. Then
they had .45 bullet dropped b y a robot arm from the same distance and released at
the exact time and guess what happened ?? They both hit the ground at the same time !!

One of the first lessons in basic physics!

[Flexmoney]

RaymondMillbrae, on Nov 20 2009, 09:50 AM, said:

Thanks, guys.

I've been doing a lot of meditating on this topic,

You might try a little research on this. All of this stuff is easily available for free and easy viewing on the internet.

I don't think anybody here is going to write or re-write the science on trajectory.

[RaymondMillbrae]

OK, OK,

I think I'm getting it.

Let's try one more scenario.

Let's say you have a barrel. Just a plain barrel without the slide or the frame...just the barrel.

Now we place the barrel in a vice, or some thingy to hold it perfectly still.

Now we make sure the barrel is totally parallel to the ground. 100% parallel.

Now we peek through the barrel and sight in on a target that is 12" inches away from the end of the barrel. (Bore-sighting). Dead center of the bullseye on a target 12" inches away.

Now we invent some contraption (use your imagination) to somehow fire a bullet as this target 12" inches away - directly in line (the boresight) of the barrel.

Will the bullet drop?

I think I am starting to understand something. It has to do with the curvature of the earth, and the natural movement of the earths rotation.

I'm still working on it, but I think that in the above scenario...I may be able to say "Yes" as well.

Let me think about it a bit more.

By the way, I also saw that MythBuster episode, and it was pretty cool. Recognize the Richmond 200-yard range? (I've seen those guys at local gun shown in my area. They are local folks).

In Christ: Raymond

This post has been edited by RaymondMillbrae: 20 November 2009 - 09:24 AM

[rvb]

RaymondMillbrae, on Nov 20 2009, 11:22 AM, said:

I think I'm getting it.

not quite yet....

RaymondMillbrae, on Nov 20 2009, 11:22 AM, said:

Will the bullet drop?

yes, slightly.

RaymondMillbrae, on Nov 20 2009, 11:22 AM, said:

I think I am starting to understand something. It has to do with the curvature of the earth, and the natural movement of the earths rotation.

not at all. has to do with the CONSTANT accelleration of gravity.

-rvb

[RaymondMillbrae]

Hmmmmm...

I guess you learn something every day.

HORIZONTAL LAUNCH

I guess "trajectories" was not the correct wording. I was speaking more specifically of "horizontal launch".

I've been schooled. (I just needed the push in the right direction to find something that could answer my "head-scratcher" in a way I could understand it).

Thanks!!!

In Christ: Raymond

This post has been edited by RaymondMillbrae: 20 November 2009 - 09:44 AM

[Powder Finger]

Here's a drop chart W/230 @ 850 0 sight height to see just drop
Range Drop Drop Windage Windage Velocity Mach Energy Time Lead Lead
(yd) (in) (MOA) (in) (MOA) (ft/s) (none) (ft•lbs) (s) (in) (MOA)
0 0.0 *** 0.0 *** 854.2 0.765 372.6 0.000 0.0 ***
5 -0.0 -0.9 0.0 0.2 847.9 0.759 367.1 0.018 3.1 59.2
10 -0.2 -2.1 0.0 0.4 841.7 0.754 361.8 0.035 6.2 59.5
15 -0.5 -3.2 0.1 0.7 835.6 0.748 356.6 0.053 9.4 59.7
20 -0.9 -4.4 0.2 0.9 829.7 0.743 351.5 0.071 12.5 59.9
25 -1.5 -5.6 0.3 1.1 823.8 0.738 346.5 0.089 15.7 60.1
30 -2.1 -6.8 0.4 1.3 817.9 0.733 341.6 0.108 19.0 60.3
35 -2.9 -8.0 0.6 1.5 812.2 0.727 336.8 0.126 22.2 60.6
40 -3.9 -9.2 0.7 1.7 806.6 0.722 332.2 0.145 25.5 60.8
45 -4.9 -10.5 0.9 2.0 801.0 0.717 327.6 0.163 28.7 61.0
50 -6.1 -11.7 1.1 2.2 795.5 0.713 323.1 0.182 32.0 61.2

just pluged in a .150 BC but this should be close
5yd .9,10yd 2.1 etc........
in this case it drops like a rock.

[Nik Habicht]

RaymondMillbrae, on Nov 20 2009, 11:22 AM, said:

OK, OK,

I think I'm getting it.

Let's try one more scenario.

Let's say you have a barrel. Just a plain barrel without the slide or the frame...just the barrel.

Now we place the barrel in a vice, or some thingy to hold it perfectly still.

Now we make sure the barrel is totally parallel to the ground. 100% parallel.

Now we peek through the barrel and sight in on a target that is 12" inches away from the end of the barrel. (Bore-sighting). Dead center of the bullseye on a target 12" inches away.

Now we invent some contraption (use your imagination) to somehow fire a bullet as this target 12" inches away - directly in line (the boresight) of the barrel.

Will the bullet drop?

Yes. Will you be able to measure the amount of drop? That may depend on the quality of the measuring instruments you can acquire....

If you hold a bullet in your hand and drop it, you can see the effect of gravity. If you fire a bullet --- you can't see the effect of gravity with your naked eye; that makes it a little harder to wrap your brain around the concept....

[Duane Thomas]

The sights on the gun ride a distance above the barrel. The makers of guns know this. If the barrel inside the gun was perfectly level relative to the sights, but below them, you could never have point of impact/point of aim because the bullet would always hit below POA. POI would begin below POA, then as gravity had its way as distance increased, POI would become progressively lower.

Knowing this, gun makers actually angle the barrels of their guns slightly upward relative to the sighting plane. The idea being that at some point the bullet, moving upward, will cross the sighting plane and, at the point, you'll have perfect POI/POA integration.

As the bullet leaves the barrel it is travelling upward, but only because, to a minor extent, it's actually being fired upward. At some point in its flight, gravity overcomes this effect and the bullet begins to drop. The bullet doesn't really shoot flat at any point in its travel, its path describes a shallow parabola, up then down.

There are actually two points at which you'll achieve perfect POI/POA integration, two distances: in close and at a much greater distance. The bullet leaves the barrel travelling upward, then it crosses the sighting plane, that's the first point at which POI/POA come into alignment. The bullet continues on past that, at which point it actually travels above the sighting plane. Then as gravity asserts its hold and the bullet begins to arch downward, the bullet crosses the sighting plane a second time.

So, basically, the progression of POI/POA relationship goes like this:

(1) In close, bullet impacts below POA.

(2) First point of integration, bullet hits exactly POA.

(3) Beyond that, bullet hits above POA.

(4) Second point of integration, bullet hits exactly POA again.

(5) Beyond second point of integration, bullet hits below POA again.

[Patrick Sweeney]

Further background: experimental data must be viewed with operational error in mind.

Let's take your 12" target and horizontal launch example. Will the bullet have dropped? Yes, Newton says so, and that's a law you can't get around no matter how good your lawyer is. Can you measure the drop? Maybe. Remember, the bullets will have spread out (formed a group) at 12", even if that group is .001"
How precisely have you measured "level" and "centered?" Any and all errors may be larger than the drop.

Your experience of holdover and lack of drop at 25 or 50 yards is experimentally lost in the data drift., You can't shoot a handgun well enough to measure the difference. The gun probably can't group much better.

Short answer; stop struggling, and accept the answers you've been given. they're correct.

[Sterling White]

Quote

I don't think anybody here is going to write or re-write the science on trajectory.

Patrick and others just did....

This post has been edited by Sterling White: 20 November 2009 - 11:54 AM

[Bill Nesbitt]

Everybody has explained the science well.

If you need to hold high to hit at 25 yards, then either your sights or technique need adjusted.