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TAREEN
10-02-2009, 04:57 PM
How accurate is this information, from your personal experience? I think those having facility of firing range can come up with an accurate answer. My question is mainly about 25 yards' elevation of bullet from line of sight.
http://3.bp.blogspot.com/_3I-p8Lp03qs/SZF4BlmR3uI/AAAAAAAAAFA/BipBmxUiXUA/s400/sighting_in_a_rifle.gif

Irttyza
10-02-2009, 05:33 PM
i think it depends on what range you zero the rifle..more experienced shooter may have more info

TAREEN
10-02-2009, 05:57 PM
as mentioned, the rifle scope is zeroed at 100 yds

Firepower!
10-02-2009, 06:10 PM
we should get together and run various tests of different calibers

Balazona
10-02-2009, 08:08 PM
GTG sounds always KOOL.lol

Conceal Carry
10-02-2009, 11:37 PM
IMHO all bullets rise above the line of sight during the first phase of their travel

Firepower!
11-02-2009, 11:49 AM
If you have 0 at lets say 100 yards you are going to get + result before hundred and - result after that. How much? You will need a software to calculate that or find a precalculated ballistic chart for certain bullet weight.

TAREEN
13-02-2009, 09:32 AM
IMHO all bullets rise above the line of sight during the first phase of their travel

That answers my question and verifies the published picture.

Thank you.

Connector
16-02-2009, 01:30 AM
Google JBM CALCULATIONS for bullet trajectory.

Skeeter60
06-08-2009, 08:30 PM
Scoped Rifle on the Range
The scope is about 1.5 inches above the line of bore.
When you zero a rifle at 100 yds the bullet begins to rise and crosses the line of scope / sight between 25 to 30 yds depending on the muzzle velocity and several other factors.
It will continue to rise till around 55 to 60 it starts to come down and again cross the line of sight at 100 yds the point of zero and then keep going down as mother earth pulls it with the force of gravity.
Ideal zero for a high velocity Rifle like a 7mm Rem Mag with a 150 gr Ballistic Tip Nosler Bullet fired at 3150 FPS is to zero it at at 100 yds so that your bullets impact 2inches above the point of aim, this way you will have a 250yd zero and your bullets will be about 5 inches low at 300 yds. There can be very slight differences in these figures depending on the Bullet used and the actual Velocity but this can be used as a guide line for both .270 Win and even a 30-06

MIdreesTaj
06-08-2009, 09:29 PM
projectile trajectory is always in a continous deceleration throughout its initial flight.. physics rule apply here... the reason is air drag. friction.
more aero bullets are better flyers
same way with a given caliber, its weight and velocity, we can calculate its ballistic co-efficients.
BCs detrmine how much a bullet flies well with minimum drag resulting in better range and predictable accuracy. the higher BC bullets are better in range and energy transmission..
and BULLET never rises from the line of sight OR bore.. it just goes forward and gradually starts dropping. its wrong to say that a bullet rises and then falls. ok

HasanJamshad
06-08-2009, 09:54 PM
I think the projectile of a bullet crosses the line of sight twice first upward and then downward. This is not because of some special physics for the bullets but due to the angle of the rifle barrel. When we zero a rifle sighting through a scope mounted high barrel of the rifle is never parallel to the ground but slightly angled upward. Projectile rises above the axis of the sight and then falls because of this angle.

Denovo87
06-08-2009, 10:03 PM
I think the projectile of a bullet crosses the line of sight twice first upward and then downward. This is not because of some special physics for the bullets but due to the angle of the rifle barrel. When we zero a rifle sighting through a scope mounted high barrel of the rifle is never parallel to the ground but slightly angled upward. Projectile rises above the axis of the sight and then falls because of this angle.

Perfectly explained, thats why there's been lot of controversy over "bullet rise" some say it rises some say it doesn't. Basicaly we have to see with scope mounted on, barrel never is paralel to ground its slightly upward.

It couldn't be explained better then that, thanks Hassan.

MIdreesTaj
06-08-2009, 10:05 PM
@HasanJamshad... u are right
exactly... the bullet doesnt go up the line of bore.. its the angle of barrel..
as optical or iron sighting travels straight - absolute straight by the rule of light, your bullet cant move straight like ur sight picture. it is a projectile and gravity works on it unlike light!
...
think of throwing a stone and hitting a stray dog.. will u throw it straight or will u arc up ur arm and send the stone in an angled flight?

Offroader2323
06-08-2009, 10:37 PM
as per my knowledge .270 is known for its flatter tragectory thats why if you zero it at 25-30 yards it will travel and hit the bulls eye at about 250 yards before start decending.

Skeeter60
06-08-2009, 10:49 PM
There is a line of sight
A line of bore
and the flight path of the bullet or Trajectory

When we sight or zero a rifle we do it in this way that the barrel points above the line of sight. In other words the line of sight is a straight line to the target.
The line of bore is forming an upward angle and the bullets angle of departure is pointed well above the line of sight.
After leaving the barrel on an upward path the bullet is pulled down wards by gravity. That is how the trajectory is formed. The highest point in the trajectory is known as Mid range Trajectory or as the Maximum Ordinate, this occurs a little ahead of the mid range point actually. The bullet only follows the line of bore and starts moving down due to gravity. the act of zeroing is to sight the rifle in a manner that the angle formed between the line of sight and the line of bore leads the bullet to the point of aim.
A bullet Never Rises above the Line of Bore ( Jump not withstanding), A bullet crosses the Line of Sight Twice first when crossing it on an upward path, and then when it comes down to point of aim.
If a Rifle was laid horizontal on a table and a Marble placed on the barrel and the Rifle fired. What will hit the ground first????
The Bullet????
The Marble????
or Both will hit the ground at the same time???? Think hard before you answer
......
,,,,,,,
........
.........
111111
!!!!!!!!!!
@@@@@@

Both will hit the ground at the same time. The Gravity is a Constant. Mother earth pulls everything whether in a state of motion or rest with the same force

,,,,,,

Turumti
07-08-2009, 01:38 PM
@Skeeter 60

Excellent reply! Most folks in Pakistan base their knowledge on hearsay and pure untruths perpetrated by gunshop owners, especially with regards to rifles. You are very right in saying that no bullet ever rises above the line of bore. But then you are preaching to the choir, they are so in love with their own hollering that they will not hear you.

Often one gets to hear talk of how flat the 22-250's trajectory is or how much better the 270 is compared to the 30-06. Muzzle velocity per se is not the only determinant of trajectory, down range velocity and retained energy, and for that, you must factor in projectile mass, ballistic co-efficient and sectional density, at the very least. Now try explaining that to the varmint calibre proponents in this country that who believe that 22-250, 223 Win. and 222 Rem. are the best calibres ever and can be used for hunting anything from ants to elephants!!

Enigmatic Desires
07-08-2009, 03:12 PM
Gravity may be constant .. but what about the weight of the projectile. Wont it effect the 'arc' that the bullet makes depending on the angle of the bore?

MIdreesTaj
07-08-2009, 08:20 PM
Gravity may be constant .. but what about the weight of the projectile. Wont it effect the 'arc' that the bullet makes depending on the angle of the bore?
yes it will, mass is one of the main players here along with velocity and air drag.

suppose a target is at 250 yards
try thinking of a 500 grain bullet propelled from S&W model 500 revolver, ur model 500 S&W is zeroed @ 250 yards, angle of elevation of barrel would be alot greater than

a .50 bmg rifle, throwing the same projectile of 500 grains. Mass is same in both the cases but velocity and air drag varies. velocity varies due to difference in charges burnt, and air drag varies due to the difference of type of bullet used.

so mass is as important as velocity and aerodynamic shape of the bullet.

Enigmatic Desires
08-08-2009, 02:54 AM
Thanks for the clarification sir :)

Skeeter60
08-08-2009, 11:55 AM
Gravity may be constant .. but what about the weight of the projectile. Wont it effect the 'arc' that the bullet makes depending on the angle of the bore?
Weight does not directly effect the trajectory.
How ever weight has a relation when you define one caliber. This is covered by Ballistic Coefficient as pointed out by a worthy member already. A 160 grain bullet of 7mm will have a higher BC than a 7mm bullet of 140 grains provided these are of exact same shape. A pointed or Spitzer bullet with a Boat tail will have a much higher BC than a bullet of same Cal and Wt & a round nose flat base bullet.

Trajectory is improved by higher velocities and higher BC.

A light bullet from any Cal with low BC, even though it will start faster at the muzzle; will be going slower than a bullet with a higher BC & Wt (same Cal ) which started a bit slower at ranges of 2 to 300 yds and .
Therefore a higher velocity and higher BC will give us relatively flatter trajectory.

Skeeter60
11-08-2009, 10:28 AM
projectile trajectory is always in a continous deceleration throughout its initial flight.. physics rule apply here... the reason is air drag. friction.
more aero bullets are better flyers
same way with a given caliber, its weight and velocity, we can calculate its ballistic co-efficients.
BCs detrmine how much a bullet flies well with minimum drag resulting in better range and predictable accuracy. the higher BC bullets are better in range and energy transmission..
and BULLET never rises from the line of sight OR bore.. it just goes forward and gradually starts dropping. its wrong to say that a bullet rises and then falls. ok

Dear Mr midreestaj,
I had chosen not to reply to your above quoted msg, but then I saw your love for Snipping and long range shooting in your later msg and thought of submitting my little bit of experience and knowledge.
A bullet starts dropping the moment it is out of a rifle barrel (not withstanding Jump) due to Gravity.
Any rifle, when zeroed or sighted at any given range, to hit point of aim, its BULLET WILL CROSS THE LINE OF SIGHT TWO TIMES GOING UP AND THEN GOING DOWN TO THE POINT OF AIM.

It does not cross the LINE OF BORE

MIdreesTaj
11-08-2009, 07:30 PM
@Skeeter60 i agree with it.. it is what to my own understanding thats happening in a bullet flight.. what i did not put right was i placed line of sight(to me line of view by an eye) and line of bore as same... i call it line of telescopic sights or iron sights. atleast thats how i have been explaining it to my friends.. :) and plz mind not the lesser essential jargon in my speech..

KageFox
11-08-2009, 07:50 PM
Very interesting info, brothers. And I wondered for months how to get my scoped air rifle to shoot constantly at point of aim...

MIdreesTaj
11-08-2009, 08:03 PM
Very interesting info, brothers. And I wondered for months how to get my scoped air rifle to shoot constantly at point of aim...

good to know fox, ive been playing with my shadow for a long time.. shooting air-piston rifles and espcially break-barrels is quite difficult.. way difficult than a firearm.. why dont u start a new thread abt air-rifles so we can talk abt these beautiful guns :)

Mumar
15-08-2009, 12:44 AM
@midreestaj
assalam-o-alikum
Air rifle discussion thread ".22 and .177 cal pellets"come join us there all Air Rifle lover are welcomed...

Conceal Carry
27-08-2009, 12:08 PM
and BULLET never rises from the line of sight OR bore.. it just goes forward and gradually starts dropping. its wrong to say that a bullet rises and then falls. ok

Sorry, I strongly disagree. Every bullet crosses line of sight twice, once when it crosses it going up and second when it crosses it coming down, and this second crossing is called zero range, this is what every one aims for. If a bullet will not cross the line of sight it will NEVER hit the target. Period.

http://img104.imageshack.us/img104/6108/33512536.gif (http://www.postimage.org/)

Bore Centerline - This is the visual line of the center of the bore. Since sights are mounted above the bore's centerline and since the bullet begins to drop when it leaves the muzzle the bore must be angled upwards in relation to the line of sight so that the bullet will strike where the sights point.

Bullet Trajectory - This is the bullet's path as it travels down range. It is parabolic in shape and because the line of the bore is below the line of sight at the muzzle and angled upward, the bullet's path crosses the line of sight at two locations.

Critical Zone - This is the area of the bullet's path where it neither rises nor falls greater than the dimension specified. Most shooters set this as 3" to 4" from the line of sight, although other dimensions are sometimes used. The measurement is usually based on one-half of the vital zone of the usual target. Typical vital zones diameters are often given as: 3" to 4" for small game, and 6" to 8" for big game and (Gasp!) anti-personnel use.

Initial Point - The range at which the bullet's trajectory first crosses the line of sight. This is normally occurs at a range of about 25 yards.

Line of Sight - This is the visual line of the aligned sight path. Since sights are mounted above the bore's centerline and since the bullet begins to drop when it leaves the muzzle the bore must be angled upwards in relation to the line of sight so that the bullet will strike where the sights point.

Maximum Ordinate - This is the maximum height of the projectile's path above the line of sight for a given point of impact and occurs somewhat past the halfway point to the zero range and it is determined by your zeroing range.

Maximum Point Blank Range - This is the farthest distance at which the bullet's path stays within the critical zone. In other words the maximum range at which you don't have to adjust your point of aim to hit the target's vital zone. Unless there is some over riding reason to the contrary shots should not generally be attempted much past this distance. In the words of the Guru, "It is unethical to attempt to take game beyond 300 meters." If you do, you should write yourself a letter explaining why it was necessary to do so. An approximate rule of thumb says that the maximum point blank range is approximately your zero range plus 40 yards.

Mid-range Trajectory - This is the height of the bullets path above the line of sight at half way to the zero range. It does not occur at the same range as the maximum ordinate height which can be greater.

Minute of Angle (MOA) - A "minute" of angle is 1/60 of a degree which for all practical purposes equates to 1 inch per 100 yards of range. (Actually it's 1.044") Thus 1 MOA at 100 yards is 1 inch and at 300 yards it is 3 inches. The term is commonly used to express the accuracy potential of a firearm.

Zero Range - This is the farthest distance at which the line of sight and the bullet's path intersect.

TAREEN
28-08-2009, 09:12 AM
Nice article Conceal Carry. Very simple & understandable to readers.

Conceal Carry
28-08-2009, 01:31 PM
Thanks Tareen Sahib.

KageFox
28-08-2009, 02:15 PM
Nicely detailed, CC. I guess the two points of intersection of line of sight and bullet trajectory are the beginning of the shot and the zero point.

Conceal Carry
30-08-2009, 10:24 AM
You got it right.



Nicely detailed, CC. I guess the two points of intersection of line of sight and bullet trajectory are the beginning of the shot and the zero point.

Malik1
30-08-2009, 12:15 PM
Gents, I,m quoting excerpts from Mike Nelson article on Bullet Trajectory - Fact and Myths. It will further reinforce what the honorable Skeeter60 and probably other worthy members said above

Myths and errors regarding the path of a bullet generally come from a lack of understanding of the forces acting on the bullet before, during, and after its path through the barrel.

One of the more pervasive myths associated with bullet trajectory is that "bullets always rise right after they leave the barrel." In general, bullets do rise after leaving the barrel, and they immediately begin to drop. This is not a contradiction, and the explanation is not difficult to understand.

Bullets are affected by gravity whether in flight or not, and, when they leave the barrel, they no longer have any physical support, such as the brass, the box, your pocket, the magazine, the chamber, or the barrel, so they begin to fall. In addition, they are traveling through air, so air resistance progressively slows their flight. On most occasions the barrel is slanted upward slightly to compensate for this immediate drop; thus, for all but extreme shots, since the barrel is aimed slightly upward, the bullet does, indeed, rise slightly after it leaves the barrel, but it bullet never rises above the axis of the barrel. (Just like a football generally rises above the player when they throw a pass. The longer the pass, the greater the starting angle, and the higher the "rise" before the ball begins to fall.)

In scientific terms, "thrown" objects, whether by hand, explosion, springs, compressed air, or other forces, are called "projectiles," their path in space is called their "trajectory," and the study of their trajectories is called "ballistics." Those who fail to understand the elementary physics of ballistics often misinterpret the configuration of barrel and the line of sight and assume that something "special" happens to the bullet during its flight. Many things happen, but nothing "special;" bullets fly just like any other projectile and are subject to the same laws of physics.


Horizontal Shot. If the barrel is horizontal to the surface of the earth when fired, the bullet never rises above the barrel, and gravity causes an immediate descent.


Typical Alignment. Generally, for what we consider a "horizontal" shot, the sight alignment places the barrel in a slightly upward tilt, and the bullet starts its arc, rises slightly above the level of the muzzle, but never above the axis of the barrel, reaches a peak, then descends.


Velocity. The velocity is a factor in determining energy on impact and the horizontal velocity determines how far the bullet travels before it hits the ground. The above illustrations apply to all ballistic projectiles whether bullets, rocks, or ping pong balls.

Low Velocity Bullets. Bullets at nominally 800 fps to perhaps 1600 fps, such as 22 LR, most pistols, and older rifle cartridges, must follow a rather high arc in order to reach a target 100 yards away. In fact, most of these slower cartridges are only useful to about 50 yards, perhaps 75 yards for some in the upper end of this range.

High Velocity Bullets. Bullets at 2600 fps and up, such as the .223, 22-250, .243/6mm, .270, .308, 30-06, follow a much lower arc to reach a target, and their useful range can be upward of 200 yards. These are often referred to as "flatter" trajectories. With higher velocities, these bullets go much further before gravity and air resistance cause them to fall below the initial line of sight.

Since the barrel is generally directed at an angle to the line of sight, sighting directly upward or directly downward results in a trajectory that deviates even more from the line of sight than the typical, relatively level shot. Still, the effects of gravity and air resistance are the same as far as the bullet is concerned, it is just that the trajectory at such a steep angle is more divergent from the line of sight.

Fact or Myth. So, does a bullet rise after it leaves the muzzle? One says, "yes." Another says, "no." Who is correct? Both could be correct because of different meanings associated with the word, "rise." They might argue incessantly, but their argument will not change the physical aspects of the path of the bullet. If they would concentrate on discussing the physical events, they would eventually conclude that they were each using the word, "rise," differently.

Skeeter60
31-08-2009, 12:33 PM
Malik1

Very nicely explained. Keep up your very good and knowledgeable posts

Enigmatic Desires
31-08-2009, 02:09 PM
Excellent post stripped of technicalese Mr. Malik

Malik1
31-08-2009, 08:35 PM
@ Skeeter60 Your appreciation is an honour Sir

@ED Many Thanks sir

KageFox
01-09-2009, 12:06 AM
As far as the barrel is horizontal, the bullet will not rise as its velocity will not have an upward vertical component. At all times, a constant downward force due to gravity is exerted onto the bullet. Like all projectiles, a bullet will follow a parabolic path.