55's and 243's

Quarterbored, don't know where you got you info, but the ballistic program I used diagrees with you.Please tell me what data you used. Maybe we are not comparing the same bullets and velocity.You said the wind drift was only 1/2 inch difference.Not likely at 400 yds with bullet of .110 difference in ballistic coefficients ,I do not need a ballitics program to see that fact.
70 grain 3700fps 945 ft lbs and 13.4 drift at 400 yds 10mph cross wind/2466fps
55 grain 4000fps 581 ft lbs and 18.7 inches drift at 400 yds.2182fps.bullet drops are nearly equal.
I am not sure a .008 seconds different in flighttime of these bullets to 400yds is going to be noticeable.At 350 yds flitght times are equal ,after that the 70 grain is faster.So you would have to engage your target at ranges well under 350 yds to have faster flight times with the 55.
Sierra infinity program ran these numbers.Check your numbers.Why would long range shooters use heavy bullets with high ballistic coefficient?
I stand by these and my earlier numbers.Your numbers are either based most likely on different criteria than mine ,different ballistics computers or were miread .
My point being regardless of all this ,, one needs to look at what downrange performance one desires and not just muzzle velocities.
I, like most others have at some point in time in the last 40 years tried to blow the same smoke up my a** as far as high muzzle velocties.Experience has shown me that if all one considers is high muzzle velocities one is not lloking at the whole picture. . While in some cases a high muzzle velocity may give you just what you want down range,that down range performance must first be looked at. PEP RALLY OVER.
 
Last edited:
Quote:
Is it normal for a 243 with a factory barrel, to not shoot 55gr nolser's. MIne shoots them great, but another site i visit had people complaining they couldn't get them to shoot. Mine are .75in or better at 100yds, and about 5in at 300yds.

They were saying that they wouldn't stabilize?? That doesn't make sense. Can you over stablize a bullet??? Just curious, i have had nothing but good with all the reloading i have done.



Sorry, been away , busy getting the holster business where I need it to be. So I'm late on a lot of post.

In regards to twist, it is always better to error on the fast side.
Is it possible to overstabilize,,,yes.
Intially it just take a little longer to "sleep"(eliminate yaw, and really at normal ranges it is not a problem.
Over stabilization may cause problem at extreme range when velocity drops into the transonic range. This velocity varies with altitude and to a point atmospheric condititions.
This roughly starts (if i remember correctly)about 1435 fps sea level.
Generally speaking the closer to optimum twist the bullet departs and figuring the errosion, the better chance the bullet has of making it through this range with inherent accuracy intact.
 
Last edited:
Point Blank Ballistics Program...

I used a 55 NBT and a 70 NBT

I am a long range shooter... and I do use high BC bullets for long range work. The high BC bullets are for wind and downrange punch, not so much the trajectory aspect. Any monkey with a rangefinder and turrets can account for drop... but the wind will eat your lunch. For longer range work (400-800) with the .243... no doubt the high BC bullets rule... but to call a 70 NBT a "high BC" bullet is a stretch to say the least.

I've killed (or seen killed) hundreds... yes hundreds of coyotes with the 55 NBT... I can count on one hand the dogs that have gone further than 10 yards after taking one. I've never seen them "splash on the shoulder"... they exit 90% of the time... I haven't seen any of this "over stabalization" myth (all the way to 1000 yards... in no wind mind you)... and using a dead-nuts hold out to about 300 yards (sighted in only 1" high at 100 and about -4" at 300) is absolutely awesome for coyote hunting. For the most part the 55 grainer kills were inside 400 yards, but there are a few that stretched out to over 5 bills. I've also killed (or seen killed) hundreds of other dogs with the 65,75 and 87 Vmax... 70 and 80 NBT... and the 85 Sierra HPBT... I know I prefer the 55 to all those bullets, unless the range gets past 400... then the 87 Vmax starts to shine.

Different programs will spew different results... but the common theme is: Shoot your data... that's the only way to truly know. My real world experience has proven the 6mm 55 grain NBT at 4k+ to be the single greatest coyote load out to 400 yards... no doubt.
 
Quote:
"... Is it possible to overstabilize,,,yes.
Intially it just take a little longer to "sleep"(eliminate yaw, and really at normal ranges it is not a problem.
Over stabilization may cause problem at extreme range when velocity drops into the transonic range. This velocity varies with altitude and to a point atmospheric condititions.
This roughly starts (if i remember correctly)about 1435 fps sea level.
Generally speaking the closer to optimum twist the bullet departs and figuring the errosion, the better chance the bullet has of making it through this range with inherent accuracy intact.



It is not possible to "over stabilize" a bullet.

This a myth that has been floating around for some 15-ish years, and it keeps getting recycled.

Nor is there any problem with the "trans-sonic" zone - myth #2.

KEEP THIS IN MIND - Once a bullet yaws, there is no way back, there is no "going to sleep", the groups will get larger, and it will eventually tumble.

It's not "my opinion" it's Newtonian physics, (which NO ONE has ever been able to challenge or disprove).

Some bullets are not strong enough to take very fast twists, but that is not an issue of over stabilization, it is an issue of jacket construction.

All this was beat to death in a thread here about 4 to 6 weeks ago.

.
 
Quote:
I don't know that I'd call it a myth,,, there is some pretty solid science behind it.

Dave



Exactly WHAT "pretty solid" science to you have.

Inquiring minds want to know...

... or are you just repeating something you heard somewhere?

.
 
if u over stabilize" a bullet dont that make it unstabilize" a bullet /ubbthreads/images/graemlins/smiliesmack.gif /ubbthreads/images/graemlins/ooo.gif
 
Quote:
if u over stabilize" a bullet dont that make it unstabilize" a bullet /ubbthreads/images/graemlins/smiliesmack.gif /ubbthreads/images/graemlins/ooo.gif



Uhhh WHAT?
 
Quote:
Quote:
if u over stabilize" a bullet dont that make it unstabilize" a bullet /ubbthreads/images/graemlins/smiliesmack.gif /ubbthreads/images/graemlins/ooo.gif



Uhhh WHAT?



If u push it past the stabilize point it become unstabilize again
 
It's either stable... or it ain't. You can't stabalize it so much that it becomes unstable. You can spin them fast enough to blow the jacket off... seen that happen more than once. But, this MYTH... yep, MYTH... that the bullet resists 'nosing down' with the path of the trajectory due to excessive gyroscopic inertia is total malarkey.
 
The science I refer to, comes from using a modern ballistic program using algorithms that aren't from early in the last century.
RSI shooting lab is the only one I know of that is using up to date technology regarding ballistics. Physics are physics, but how it is applied or how it is computed is another matter.
Now I'm no comp shooter but do play at long range, and beyond my novice study of ballistics over 30 years, I'll admit I still am learning. It has been proven, that if a bullet has less than GSF (gyro stability factor)less than 1.2 by the time it reaches transonic range, taking into account your rpm errosion (depending mostly barrel configuration and condition), and you end up with a GSF less than 1 at that range, chance of it remaining stabile through that range are slim to none. If the bullet is "over stabilized" with a GSF of 1.5 when it leaves the muzzle, it enters transonic range with a slight nose up attitude. This stands a better chance at making it through, but if there any slight inconsistancies in it construction, the buffeting will raise heck] with it.

When it comes to heresay, I only repeat what I have been taught or told by those who make a living on such matters, and have far more experience in the field than I.
But why I want to read what was said in the other thread, I like to see what documentation is presented that will prove what I have learned over the years wrong.
But unless it comes from PHD that deals with ballistics, I have to go with what I know for now.

Dave
 
Quote:
Quote:
Quote:
if u over stabilize" a bullet dont that make it unstabilize" a bullet /ubbthreads/images/graemlins/smiliesmack.gif /ubbthreads/images/graemlins/ooo.gif



Uhhh WHAT?



If u push it past the stabilize point it become unstabilize again



Maybe you want to explain that (in real scientific terms), or did you just make that up?

.
 
Quote:
Quote:
Quote:
Quote:
if u over stabilize" a bullet dont that make it unstabilize" a bullet /ubbthreads/images/graemlins/smiliesmack.gif /ubbthreads/images/graemlins/ooo.gif



Uhhh WHAT?



If u push it past the stabilize point it become unstabilize again



Maybe you want to explain that (in real scientific terms), or did you just make that up?

.



sorry no scientific terms there lol if u push it past its stabilize point it become unstabilize ,
If ur car is listed a stable at 70mph and no more and u speed up to 160mph u have passed the cars stable point and u go all over the road or into a tree
 
Quote:
Use the search function - I don't remember the title.

.


4 searchs with no find...maybe somebody else knows where to look?
 
Quote:
The science I refer to, comes from using a modern ballistic program using algorithms that aren't from early in the last century.



You make a mistake thinking that I am using ballistics from early in the last century - I am talking about current ballistics.

Quote:
RSI shooting lab is the only one I know of that is using up to date technology regarding ballistics. Physics are physics, but how it is applied or how it is computed is another matter.



I have all the RSI programs since it was a Beta test - I was one of the Beta testers - I have spent over 30 hours talking to Jim Ristow about ballistics - your point is????

Aw crap - here we go again.

Physics is physics - and you don't have ANY options on how you apply it or how you compute it. It works the same way all the time, or it isn't physics.

Quote:
"... It has been proven, that if a bullet has less than GSF (gyro stability factor)less than 1.2 by the time it reaches transonic range, taking into account you rpm errosion (depending mostly barrel configuration and condition), and you end up with a GSF less than 1 at that range, chance of it remaining stabile through that range are slim to none.



Exactly WHO proved it and where and when! This is pure BS.

In Scotland, there is a rifle range that has targets at 2,000 and 2,200 meters, and they shoot 303, 308 and 30-06 rifles at these ranges.

How do that bullets get all the way out there if the have to pass the forsaken "Trans-sonic" zone.

There was a very lengthy thread on Benchrest.com about this subject, and it was completely dismissed as BS - it is a waste of time, and simply not true.

Quote:
If the bullet is "over stabilized" with a GSF of 1.5 when it leaves the muzzle, it enters transonic range with a slight nose up attitude...



All bullets travel with the nose in exactly the same angle as they were when fired (unless they tumble) - if they are fired at a 20 degree angle, they hit the ground at 20 degrees.

Further... there is no "trans-sonic" zone. As a bullet slows down the two sonic waves get smaller and smaller and when the bullet is just above the speed of sound, the waves are almost imperceptible - when the bullet gets to the speed of sound, the waves just disappear without fanfare - there is no turbulence or buffeting - no nothing except that the BC jumps to two or three times what it was above the speed of sound, and since the waves are not there any more, the loss of energy and velocity lessens.

Quote:
This stands a better chance at making it through, but if there any slight inconsistancies in it construction, the buffeting will raise heck with it.



There is NO buffeting - bullets have been studied with sparkgraphs at all speeds from a few hundred fps to over 7,000 in air and over 20,000 in Helium - there are NO sparkgraphs showing buffeting - I did this stuff at Columbia University for a year and a half. The buffeting does not exist.

Air flow across a bullet is smooth, with a major wave coming off of the nose, and a minor wave coming off the tail.

Quote:
When it comes to heresay, I only repeat what I have been taught or told by those who make a living on such matters, and have far more experience in the field than I.
But why I want to read what was said in the other thread, I like to see what documentation is presented that will prove what I have learned over the years wrong.
But unless it comes from PHD that deals with ballistics, I have to go with what I know for now.

Dave



I asked you...

"Exactly WHAT "pretty solid" science to you have.

Inquiring minds want to know...

... or are you just repeating something you heard somewhere?
"

You gave me NO "pretty solid science" You gave me more myths.

You do not know or understand this stuff - you are saying what you heard - myths in, myths out.


-

Here's a list of common garbage I hear on the net:

1 - Bullets leave the barrel, turn off course, then 100 or 200 yds down range, they (mysteriously) turn back toward the original path, and when they get there, they make a THIRD turn to be on path again - with no explanation of what makes the bullet turn, or how it knows when to turn and what direction to turn.

1a - (a variation on 1) Bullets turn up and right, after leaving the barrel.

2 - Bullets follow the arc of the trajectory (like an arrow) with no explanation of what force makes them turn nose down, or what happened to about 5,000,000,000 pages of physics that mandate that if a spinning bullet is pushed nose down, it ALWAYS TURNS LEFT - no exceptions - never ever - it's called procession.

3 - When working up loads, as you approach maximum pressure, the muzzle velocity stops increasing.

4 - That you can tell dangerous pressure with a chronograph.

And there are about 10,000 more...

.

 
Quote:
Quote:
Quote:
Quote:
Quote:
if u over stabilize" a bullet dont that make it unstabilize" a bullet /ubbthreads/images/graemlins/smiliesmack.gif /ubbthreads/images/graemlins/ooo.gif



Uhhh WHAT?



If u push it past the stabilize point it become unstabilize again



Maybe you want to explain that (in real scientific terms), or did you just make that up?

.



sorry no scientific terms there lol if u push it past its stabilize point it become unstabilize ,
If ur car is listed a stable at 70mph and no more and u speed up to 160mph u have passed the cars stable point and u go all over the road or into a tree



That is the dumbest comparison I have ever heard...

Bullets are not cars, and cars don't have gyroscopic stabilization... and this has nothing to do with anything.

.
 
I hope its not the same science that tells every one there is man made global warming /ubbthreads/images/graemlins/ooo.gif /ubbthreads/images/graemlins/ooo.gif
 
Quote:
I hope its not the same science that tells every one there is man made global warming /ubbthreads/images/graemlins/ooo.gif /ubbthreads/images/graemlins/ooo.gif



There is no science to global warming... along with voodoo ballistics.

-
 
Back
Top