over stabilized bullets

Originally Posted By: orkan
I can take you out anytime you like, anywhere you like, with a .375CT, and show you a 1" group at 100yds, that will stay a 1" group out to about 400-500yds.


Originally Posted By: CatShooter
... Ledyard Sportsman's Association, Ledyard Connecticut. Any Saturday you like.


Let's get it on!!



 
I know this thread has veered off into a slightly different direction since it began, but here's an interesting link that gets back to the original subject.

http://www.navweaps.com/index_tech/tech-043.htm

It seems to me that precision trajectory calculations would be impossible if a projectile did not maintain an orientation where the axis of rotation did not closely follow the trajectory. Whether or not Mssr. Jurens explains how this happens is technically correct is immaterial. It does happen and it happens because of aerodynamic forces, and gyroscopic force can override them if too much is imparted.
 
Originally Posted By: orkanI'm not sure what shocks me more. The fact that you think a 1" group with a 375CT is so difficult at 300-400yds, or the fact that you are so determined to convince others that it can't be done.

In the last year, I've seen 4 people buy DTA HTI rifles in 375CT using factory ammo whom have replicated what I'm describing.

Your continued denial of the facts which others and I have seen repeatedly with our own eyes has me laughing at this point. Yet it has been my experience that the more knowledge someone has, the harder it is for them to acknowledge new principles. By that definition, I have no doubt that you are quite informed.

I'd remind you of this:
“When the debate is lost, slander becomes the tool of the loser.”
- Socrates

I'll leave this thread with a simple fact of physics. Spin stabilized projectiles will behave differently, based on shape, composition, launch velocity, and rpm of the projectile.

For the further consideration of those that would try to downplay the above laws of physics... I'd refer you to a post by Russ @ DTM. Not a whole lot of people with the experience he has with a .375CT. He does it for a living... 50-60hrs a week, and then for himself in his spare time. You can't buy that kind of experience, and he shares it for free to those willing to listen.

http://forum.snipershide.com/elr-beyond-1000-yards/215911-375ct-100yd-groups-vs-300yd-groups.html

It's clear that "cat" will be allowed to say whatever offensive comments he wants in this thread, stifling the conversation, in a feeble attempt to convince people how what others and I have seen is false. For that reason, I'll refrain from posting any further. However, the rest of you can feel free to PM me if you want to further discuss how/why this strange bullet behavior happens.

I never said that any caliber is not capable of 1" groups - I challenge your statement that a gun which is not capable of smaller than 1" groups at 100 yeard, will shoot 1" groups at 40-500 yards with the same load.

"I'll leave this thread with a simple fact of physics. Spin stabilized projectiles will behave differently, based on shape, composition, launch velocity, and rpm of the projectile. "... that is NOT a fact in any physics in the USA. That is only your statement, which does not hold water.

The physics of rotating bodies is very clearly defined, and, unfortunately, your version does not fit.
 
Originally Posted By: RiverRiderI know this thread has veered off into a slightly different direction since it began, but here's an interesting link that gets back to the original subject.

http://www.navweaps.com/index_tech/tech-043.htm

It seems to me that precision trajectory calculations would be impossible if a projectile did not maintain an orientation where the axis of rotation did not closely follow the trajectory. Whether or not Mssr. Jurens explains how this happens is technically correct is immaterial. It does happen and it happens because of aerodynamic forces, and gyroscopic force can override them if too much is imparted.




I spoke to the head of the artillery instruction at West Point, and he is not sure how they fall... the tables are empirical in nature.

I spoke to the head of naval gunnery at Annapolis and he didn't know - he referred me to some one else.

But... if sometimes the shell flies pointing in the same direction as launched, and sometimes it follows the arc, then why don't we have different BC's and ballistic tables for what twist the bullet is fired in - now this is childs play...

If you shoot a 50gr bullet out of a 14" twist, AND a 7" twist... if what the proponents of the tangent theory are correct, we would need two VERY different BC tables... but we don't!!

In fact every bullet would need a bunch of BCs depending on the twist you were going to shoot them in... and when they followed the arc and when they didn't... and they don't!

You guys can come up with all the stuff you want, but until you can answer a few basic questions, it is all BS.
 
So you are saying that the projectiles fired from naval guns do not maintain a nose-first attitude, yet calculations reliably predict where they will impact regardless of the exaggerated trajectory?

I'd say you are fairly trapped by your own words. My work is done here.
 
Originally Posted By: RiverRiderSo you are saying that the projectiles fired from naval guns do not maintain a nose-first attitude, yet calculations reliably predict where they will impact regardless of the exaggerated trajectory?

I'd say you are fairly trapped by your own words. My work is done here.


I am amazed at what I am to have said - and when I go back and look, it's not there.

I'm glad you are done - now I can take my boots off.
 
When I posted Nennstiel's depiction of the flight of an overstabilized bullet, you said all stabilized bullets fly like that. That thread is locked and you cannot edit the statement.

I know you're a smart fellow and I know you've forgotten more about ballistics than I know. I really wish you would share your knowledge without being so disagreeable and eager to bust other folks' chops. I do not have to be right all the time, all I want is to find truth and share it. There's such a thing as too much pride.
 
Originally Posted By: RiverRiderWhen I posted Nennstiel's depiction of the flight of an overstabilized bullet, you said all stabilized bullets fly like that. That thread is locked and you cannot edit the statement.

I know you're a smart fellow and I know you've forgotten more about ballistics than I know. I really wish you would share your knowledge without being so disagreeable and eager to bust other folks' chops. I do not have to be right all the time, all I want is to find truth and share it. There's such a thing as too much pride.

I don't start out rude or unpleasant, I get that way from constantly dodging BS from people that keep trying to "Win" a conversation that is not a contest. Go back and read this crap from the beginning and you will see how it developed. IT gets real old, dealing with people that have no understanding of something they heard it or read in on the internet, and they want to argue it, even though they do not understand it well enough to explain it... it gets real old, real fast.

That's right - I did say that... I do not retract it.

This is a spinning gyroscope... when you put a force on one end to pull it down, (or any other direction) it dies NOT go down, it turns 90° to the force - it ALWAYS turns 90° to the applied force, neither you or I and anyone on the internet can change that.

By the way... your friend, Nennstiel, doesn't answer his emails about gyroscopes and Newton's laws of motion... why do you think that is?

In the video at the bottom of the page, this gyro is suspended in a gimble so it can move in axis, in any direction. Notice that in this video, on the nose of the gyroscope, a heavy metal weight is hung from one end. It does NOT pull the nose down, ever - it causes the gyro to turn at 90° to the force of the weight - to change the direction of any bullet, you must have an external force, and that must be explainable in fact, not "I think", or "I read it on the internet".

http://physics-animations.com/Physics/English/gyro_txt.htm

Enjoy it.
 
As I've already revealed, I work with gyros---both mechanical and fiber-optic, and airborne navigation systems each and every day. I am comfortable saying I am quite familiar with the behavior of a gyro. I'll also say that I always find gyros to be fascinating.

A bullet is also affected by aerodynamics---specifically the Center of Pressure, and that is the force that works to keep the nose of a bullet pointed in the same direction as the trajectory so long as the gyroscopic force is not so great as to override it.

I can't speak for Nennstiel. Maybe he'll answer you one of these days.
 
Originally Posted By: RiverRiderAs I've already revealed, I work with gyros---both mechanical and fiber-optic, and airborne navigation systems each and every day. I am comfortable saying I am quite familiar with the behavior of a gyro. I'll also say that I always find gyros to be fascinating.

A bullet is also affected by aerodynamics---specifically the Center of Pressure, and that is the force that works to keep the nose of a bullet pointed in the same direction as the trajectory so long as the gyroscopic force is not so great as to override it.

I can't speak for Nennstiel. Maybe he'll answer you one of these days.

But the air pressure is not enough, and bullets are not aerodynamic.
 
The center of pressure being forward to the center of gravity is what causes a bullet to tumble if it is has no (or insufficient) gyroscopic stabilization. It's the balance of gyroscopic force to the center of pressure that allows the nose to nutate slightly, and as it does gyroscopic precession applies force at a 90-degree angle to counter that tendency. Nutation occurs continually as does the precession force which is "chasing" the changes in the center of pressure caused by nutation. There is always a small error in the bullet's orientation that is constantly being corrected.

Learning this has been interesting. What I personally find interesting is the similarity to the way a phase locked loop operates---there is always a tiny bit of error in oscillator frequency that is being "chased" by the control circuitry and that error HAS to be there for the concept to operate. Any of you guys with a background in electronics can appreciate that, I think.
 
Jesus...

Bullets don't "Nutate"!!

They fly straight or they precess... once they precess, there is no going back.

The precession is destructive and leads to tumbling.

You need to get this stuff straight.

My RugRat knows this stuff. He learned it in high school physics.
 
Originally Posted By: CatShooter
I spoke to the head of the artillery instruction at West Point, and he is not sure how they fall... the tables are empirical in nature.


I spoke to the head of naval gunnery at Annapolis and he didn't know - he referred me to some one else.


Cat, IF your asking, then you do not know. Or you do not know one way or the other. amazing how you get on here and try and tell us otherwise.


Originally Posted By: CatShooter
But... if sometimes the shell flies pointing in the same direction as launched, and sometimes it follows the arc, then why don't we have different BC's and ballistic tables for what twist the bullet is fired in - now this is childs play...

If you shoot a 50gr bullet out of a 14" twist, AND a 7" twist... if what the proponents of the tangent theory are correct, we would need two VERY different BC tables... but we don't!!

In fact every bullet would need a bunch of BCs depending on the twist you were going to shoot them in... and when they followed the arc and when they didn't... and they don't!




Bullet do follow the arc they travel, in general they do, as long as they are not under stabilized or over stabilized. There is a huge comfort margin a bullet can spin or velocity range

Bullets do have different BC drag at different velocities, most manufactures list optimum BC, that is usually at the fastest fps range, the speed of air going over a bullet has an impact on how much drag they have. Berger list average BC from 3000-1500 fps

Sierra list BC at different velocities,
I think Sierra Bullet engineers knows what they are talking about, they list.
Example They list a .284 180 MK at .660 BC at 1650 and faster, but only .610 BC 1500 fps and slower.

The 175 smk has a .505 BC above 2800 fps, .496 BC from 1800-2800 fps, .485 1800 and down.

So if you launch a 175 SMK from a 308 SPS at 2650 fps, the BC is going to be .496 like Sierra says it is, not the .505 BC that Catshooter thinks it is.

A Bullet in general will fly to the same arc it travels.
too much spin can cause excessive wobble and fail to let bullet nose down.


Originally Posted By: CatShooter
You guys can come up with all the stuff you want, but until you can answer a few basic questions, it is all BS.


Well Cat, I know this from EXPERIENCE, not just opinions. I seen there was a thread before this one you had the mods shut down from your excessive flaming. I never thought a bullet could be over stabilized either, only under stabilized.

Most people will never know this, most are not as crazy as me to try and use small varmint bullets out to 600 yards with a 10 twist when much better longer higher bc bullets are there.


Funny how you seem to hijack everyone's thread you don't agree with. a little debate is a good thing, we can all learn something, but post after post after post of debunking everyone's experience as "BS", or how what they use is not good enough, or how ur gun is bigger than theirs, or better.

Sometimes Cat, you do have helpful info. other times your out to try and make others look like fools. Most of the time is doing so, you make yourself look more like one that the guy your attacking. I'm around 50 and I'll admit I even learn something from the 25-35 year olds in firearms.

Since you said you had a 25-06, why don't you buy some 90 Blitzkings, load them up to 3570 fps, shoot them out to 200-400-600+ yards, and see if they hold to the drop charts.. See if it hits low and right a ft at 600.
All guns are different, so maybe yours may not do this.

There have been some helpful insightful people reply here, some of them have left, please keep the degrade tone to a minimum.
Thanks
 
My problem with all this is that i am having a hard time actually learning anything from this....i appreciate th links to articles, but it sucks when they are contradicted by other articles... On the internet, its hard to tell science from fiction to someone that doesn't know the difference.

I understand that one person's experience says this happens and can be confirmed by other people. And i understand some of the most basic laws of physics and the point that is trying to be made there...

I have a hard time with someone telling me to trust them about how it works when physics is not on their side... From my limited understanding, i would think there is something wrong with either the gun or the bullet causing them to wobble. This would be much more pronouced at 100 where their speeds are higher but settle down at longer ranges... But if the wobble is not consistent, how can the end result be consistent? Similar to a tire being out of balance and how its bounce is much more pronounced at certain RPM...

Sorry, my pea brain just cant see this through to a consistent group... I have no experience with this caliber, but i wish i did... I have seen a number of 338L guys shoot moa at 300, 2 moa at 600 and then back to 1moa at 1k... Its not a every day thing, maybe a 1 out of 10 thing, if that.. Just enough to know it can happen... We usually just attribute it to the shooter or the conditions..

Which takes me to my last point. I have a friend that never shoots at 100 because it bores him. If you take him shooting at 100 he just screws around. Mocking you, shooting once or twice and then disappears. At 300 he is so so. Half into it. When the targets get out to 600 he turns into a different person with a lot of focus. At 1k he is surgon like. Its amazing to watch his transformation. He almost always shoot a lower moa at longer ranges just because he tries harder.
 
Originally Posted By: scott2506
Cat, IF your asking, then you do not know. Or you do not know one way or the other. amazing how you get on here and try and tell us otherwise.




That is an incredibly stupid remark. Do you have any idea when the call was made, or why?
 
You're done, catshooter. You've been proven wrong. Swallow your pride and cut your losses and admit your error like a man if you have it in you. We're all watching.
 
Originally Posted By: RiverRiderYou're done, catshooter. You've been proven wrong. Swallow your pride and cut your losses and admit your error like a man if you have it in you. We're all watching.




lol.gif
 
Originally Posted By: captninsanoFrom my limited understanding, i would think there is something wrong with either the gun or the bullet causing them to wobble. This would be much more pronouced at 100 where their speeds are higher but settle down at longer ranges



No sir. A projectile is either Gyroscopically stable or it isn't. Period. If it is not stable at the muzzle, it never wil be. That is what CS is saying, some just get ruffled too easily to see what is actually being said. A projectile doesn't become stable magically at some point down range, nor does it hit an invisible wall down range and become unstable(Trans-sonic instability), atleast not in real world distances.


Chupa
 
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