Home Forums Hunting & Shooting Long Range Hunting Ladder test, How, why?

Laugh it up, fella.
Do you even realize how far your barrel would have to deflect to get the result you have shown?

I'm done, as I can no longer pull a gear low enough to deal with your stupidity.
Please, continue to lick glass and post results...

R.

Well you showed up, is that who you're talking about?

Oh wait we had to mention 'tards first, too...

Tanner

Nah.... I just been hangin out here watching the show...

I'm really thinking about sending that Travis guy a deposit on a 'Flave Precision rifle.... I wonder if he has an upgrade option on the beer?

you gotta purchase your own brews if you plan to drink em. 'Flave only sends empties

sometimes there's not even a 'Flave Precision Rifle in the box, just the empties. it's still worth the cost

A really, really small fraction of what might be called an "amount".

But I'm sure you think it's like something that could be measured with a ruler.

LOL

Yeah. Texans...



Travis

I may sell 'Flave Precision and start a new company with Tanner and aalf.

It will be called Team Indifference.

"You'll get your rifle back...maybe..."


Travis

Exactly.



Travis

And the motto...

"If we can't flock ya, nobody can"

Does that mean Tuner is getting the "package" handler position?

Only the empty box used for packaging..The cans are smelted to make his proprietary bedding block, which expands at the same rate as the scope..

And WTF is mathman with a ruling on this deflection angle thingy..I swear the one time that guy could be useful..

I really like the idea of ladder tests, but I have two problems with how they are traditionally done:

1) every barrel and load is subject to some random variation in POI. Only firing 1 shot per charge weight does not adequately take into account this variation

2) wind can and does often have a vertical component in anything but perfectly flat terrain. At any distance much beyond about 200 yards this begins to impact POI

These two sources of variation can skew results and prevent them from being repeatable with a given barrel/load combination. If using a method like this, I prefer the OCW method (which I have used successfully, in addition to the traditional ladder method), as it tends to mitigate these sources of error better, but I usually find excellent results simply by kissing, mashing the pedal, and loading straight ammo.


These were all shot using the kiss/mash pedal method...


525 yards

The amount of bullet deflection caused by barrel angle to LOS is one part of the equation, muzzle velocity is the other. Without knowing how much velocity variation there is between different powder charges, you can't accurately determine the difference in POI caused by different barrel positions.

EDIT: BUT, assuming equal velocity, a 1" vertical deflection at 600 yards, and a 24" barrel, the muzzle would have to move roughly 0.0011", and 6" of vertical would require 0.0067"

Get your yardstick out rman!

Jordan,

Brian Litz has written about this, "Magnus Affect" and spin drift. Direction of spin has an affect (changing vertical up or down), and the crosswind can destabilize the bullet which affect vertical due to lower aerodynamics.

Jason

From wiki (don't have Litz's quotes on hand):

Magnus effect

The Magnus effect. V represents the wind, the arrow F is the resulting Magnus force towards the side of lower pressure.

Spin stabilized projectiles are affected by the Magnus effect, whereby the spin of the bullet creates a force acting either up or down, perpendicular to the sideways vector of the wind. In the simple case of horizontal wind, and a right hand (clockwise) direction of rotation, the Magnus effect induced pressure differences around the bullet cause a downward (wind from the right) or upward (wind from the left) force viewed from the point of firing to act on the projectile, affecting its point of impact.[31] The vertical deflection value tends to be small in comparison with the horizontal wind induced deflection component, but it may nevertheless be significant in winds that exceed 4 m/s (14.4 km/h or 9 mph).
Magnus effect and bullet stability

The Magnus effect has a significant role in bullet stability because the Magnus force does not act upon the bullet's center of gravity, but the center of pressure affecting the yaw of the bullet. The Magnus effect will act as a destabilizing force on any bullet with a center of pressure located ahead of the center of gravity, while conversely acting as a stabilizing force on any bullet with the center of pressure located behind the center of gravity. The location of the center of pressure depends on the flow field structure, in other words, depending on whether the bullet is in supersonic, transonic or subsonic flight. What this means in practice depends on the shape and other attributes of the bullet, in any case the Magnus force greatly affects stability because it tries to "twist" the bullet along its flight path.[32][33]

Paradoxically, very-low-drag bullets due to their length have a tendency to exhibit greater Magnus destabilizing errors because they have a greater surface area to present to the oncoming air they are travelling through, thereby reducing their aerodynamic efficiency. This subtle effect is one of the reasons why a calculated Cd or BC based on shape and sectional density is of limited use.

Sooo

Aerodynamic jump, as described by Brian Litz:

Litz Linky

Aerodynamic jump is what causes groups to slant when shot in varying wind conditions. Basically, when the bullet exits the muzzle into a cross wind, the bullet tries to yaw slightly to align itself with the airflow. When the bullet yaws to the side, gyroscopic action causes it to nose up or down by a small amount depending on the wind direction. This initial yaw has an effect on the trajectory, and is known as aerodynamic jump. The more severe the crosswind, the more pitch the bullet ends up with. Flying to the target at a pitch angle will result in an elevation error that �s proportional to crosswind. This is evidenced by the slant of the impact area.

Yep


The only way bullet impacts while firing at the same POA can vary like this is a shooter with his head up his azz and the Magnus Effect


[bleep] hilarious!

This is all really great stuff..