55's and 243's

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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.





I might have missed something, but doesn't the direction of the turn depend on which way the rifling twists?
 
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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?

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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.

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Ok I'll concede, you surely sound like your depth of knowledge exceeds mine. You bring some interesting points that I ha not heard, but willing to listen.
One point though, I heard a lot of "I did" and yet no documentation. So if I repeat you, is it fact or hearsay?
Give me some links to the data in the testing please.
But dang,,,, now I know why I hadn't been here in so long.
The attitudes are tweeking!
 
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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.





I might have missed something, but doesn't the direction of the turn depend on which way the rifling twists?



Virtually ALL rifles have rifling is clockwise from the shooters position - if it is CCW, then the bullet turns right.

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[Ok I'll concede, you surely sound like your depth of knowledge exceeds mine. You bring some interesting points that I ha not heard, but willing to listen.
One point though, I heard a lot of "I did" and yet no documentation. So if I repeat you, is it fact or hearsay?
Give me some links to the data in the testing please.
But dang,,,, now I know why I hadn't been here in so long.
The attitudes are tweeking!



"So if I repeat you, is it fact or hearsay?"

Don't repeat me - go read some physics books and understand it for yourself - then NO ONE can play with your mind.

Read up on Newton's Laws of motion, and the physics of gyroscopes.

When you "really" understand these two topics - enough so you can't be BS'ed, you will be amazed at the amount of BS floating around about bullets and ballistics.

There are no exceptions to the physics of Newton or gyroscopes - If you should find even one exception, you will win a Noble Prize in Physics (worth about $11,000,000) and have a large university named after you.

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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.





I might have missed something, but doesn't the direction of the turn depend on which way the rifling twists?



Virtually ALL rifles have rifling is clockwise from the shooters position - if it is CCW, then the bullet turns right.

.



Thanks for your answer, its what I thought but I was wondering if I had missed anything.

Since we're on the subject, what would make a bullet turn down? I'm not a ballistics expert, but it would seem to me that most bullets have a weight bias towards the rear, which would not only help to keep them stable, but prevent a downward turn.
 
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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.





I might have missed something, but doesn't the direction of the turn depend on which way the rifling twists?



Virtually ALL rifles have rifling is clockwise from the shooters position - if it is CCW, then the bullet turns right.

.



Thanks for your answer, its what I thought but I was wondering if I had missed anything.

Since we're on the subject, what would make a bullet turn down? I'm not a ballistics expert, but it would seem to me that most bullets have a weight bias towards the rear, which would not only help to keep them stable, but prevent a downward turn.



For a long time, it was believed that bullets flew like arrows, the point following the arc.

The problem with this "theory" was that it defies all known laws of physics.

About 15 years a ago, some people started saying the garbage about over stabilization - they divided bullet flight into "stable" and "OVER stable", and claimed that stable bullets followed the tangent of the arc, and over stable bullets stayed pointed at the angle that they were launched.

The problem with this "theory" (besides breaking about a dozen laws of physics) is that if two bullets are fired from equal rifles, say 223 rifles, and one uses a 14" twist, and the other uses a 7" twist, and the 7" bullet is "over stabilized", then as the bullets fly down range (if the theory was true) then the 14" bullet would always be "point on" into the wind, and the 7" bullet would start showing more and more of it's "underbelly" as it flew falling down but pointing up, so it's BC would drop faster than the bullet that was following the tangent of the arc...

... but they DON'T!

The bullets from the 14" twist, and the 7" twist require the same adjustments for elevation at 1,000 yds, so, ergo, they have the same drag, so they are showing the same flight attitude for the whole trip.

So to answer your question directly, they do NOT turn nose down - they hit the target (or the ground) pointing at the same angle that they were launched.

This is a hard thing for some people to believe - they hae been watching cartoons as a kid that showed bullets falling down on Elmer Fudd point first and arrows falling point first, so it is drilled into our brain that all pointy things fall point first...

... but take a blank arrow, and sharpen the front end with a pencil sharpener, with no feathers - just a straight wooden shaft, and shoot it - it does NOT fall point first - it needs feathers on the tail to fall point first.

Mortar rounds have tail fins so they hit point first.

Artillery rounds don't hit point first - at long range, they fall into the target sideways.

The libraries at West Point and the US Navel Academy are full of photos of large shells coming in on targets sideways - pointing up at the angle they were fired.

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+1... thanks for the info Cat...

Here's a questions though... I've seen evidence on a couple of occasions that faster twist rates can actually have a positive effect on the BC of a bullet. I have an article at home (I know... I know... gun rag... grain of salt) where the author conducts an experiment firing a .22-250 with identical loads (10-15 different bullets in the 40-60 grain range) from a 1/14" barrel and a 1/9" barrel... in every instance the BC (measured over the first 100 yards) was higher, sometimes significantly, when the rounds were fired from the 1/9" barrel... How is this possible?
 
I think it's actually a bit better than that... I used .300 when I was building a drop chart and it seems like it was a 1/2-3/4 minute flatter than that at 800 yards.

I will relate this little anecdote about the 55s in my 6mm Rem: When I first started loading the 55s I was at the range with a buddy of mine... he was shooting the rifle at a target in the 300 yard berm... I was watching through the spotting scope about 25' away. What amazed me most was how fast the bullet got to the target... I could seriously see the bullet impact in the berm... before I heard the gun go off. I've been around fast .22s my entire life... half my extended family shoots .22-250s and Swifts... but I'd never seen anything like those 55s at 4100!! We were shooting a .223 with 50 grain NBTs at the same target... in about a 5-8 mph wind, the .223 drifted about 16-18"... the 6mm was about 6". The next day it was into the field with the 55s... two dogs got absolutely pole-axed by the 55s that afternoon... and it was off to the races.
 
thanks .25 bore!

I may give them a go in the 6x45. Could probably get them going almost 3100fps out of the 16" barrel. Right now it shoots 60gr HP lights out, but their measly b.c. stinks in the wind at the speed I'm pushing them.

Looks like the 55s could cut the wind hold in half from the 60s...
 
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+1... thanks for the info Cat...

Here's a questions though... I've seen evidence on a couple of occasions that faster twist rates can actually have a positive effect on the BC of a bullet. I have an article at home (I know... I know... gun rag... grain of salt) where the author conducts an experiment firing a .22-250 with identical loads (10-15 different bullets in the 40-60 grain range) from a 1/14" barrel and a 1/9" barrel... in every instance the BC (measured over the first 100 yards) was higher, sometimes significantly, when the rounds were fired from the 1/9" barrel... How is this possible?



Take two grains of salt and call me in the morning.

The only way to do an accurate comparison of BC is to shoot drop tests at long range.

Chronographs are not accurate enough from round to round for a comparison like that.

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What amazed me most was how fast the bullet got to the target... I could seriously see the bullet impact in the berm... before I heard the gun go off.



Funny you say that, I had a friend tell me the same thing the first time I shot 55's thru my 6mm Rem. I was testing them at 100 yards, he said, I can see the wood flying off the back of the target before I hear the boom of the rifle.
 
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Take two grains of salt and call me in the morning.

The only way to do an accurate comparison of BC is to shoot drop tests at long range.

Chronographs are not accurate enough from round to round for a comparison like that.

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I hear ya...
 
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Take two grains of salt and call me in the morning.

The only way to do an accurate comparison of BC is to shoot drop tests at long range.

Chronographs are not accurate enough from round to round for a comparison like that.

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I hear ya...



I had a "Come to Jesus" meeting with a bunch of chronographs about five years ago.

About 10 years ago, I was talking to Ken Oehler and we got on the subject of how do you calibrate a chronograph.

I mean, suppose your chrono says your bullets are doing 4,000 fps.

How do you know that it is 4,000 - might be 3940 or 4085, or whatever - kinda like calibrating your car's odometer for error with 10 miles worth of highway markers...

Since shooters have complete, total, God-like trust in their chrono (even if it cost $29.95), I thought it might be interesting to find out how trustworthy these things are.

All the Chrono's use the same $2 clock chip and it runs at 4 megacycles - so if it is off, that might be a source of error - then you could adjust the trap spacing to make up for the clock error - that was my thinking at the time...

... after about 45 minutes of brain storming, we came to the conclusion that there was no practical way to calibrate it, and you just took the numbers from the screen and that was what you got, +/- some unknown... and you had a very good idea of the speed, but not down to the foot (would that only be true).

End of chapter one.

Chapter two

I (like many others) from time to time had odd readings from my chrono - like one day when I shot one of the smallest groups I had ever shot, and the ES was 130 (/ubbthreads/images/graemlins/confused.gif) and other times when I was working up loads with known stable combinations, and the ES would go from 8 to 47 to 21 to 51 to 13 to... whatever???

So, on a whim, about 5 years ago, I lined up 4 Chronos in a line - each with a 4ft rail, and 5 feet apart.

The four were a Oehler 33, an Oehler 35P, a CED, and a Pact.

Care was used with a setup jig so that the bullet would fly 2" over the light port on every trap.

The rifle was a proven long range benchrest rifle whose loads were stable, and based on the groups at 600 yds, the ES was dammn tiny.

Based on the spacing of the different rails, the difference in the chrono readings should have been 7.5 fps, so if the first one said 3,500, the next ones should 3,492.5, 3,485, 3,477.5, and 3,470.

That's easy!

On the first shot, the numbers were all over the place. I looked at them and it was clear that there was no steenkin 7.5 fps difference - there was ~85 fps from the highest to the lowest, and the others were spread all over.

So I figured that the errors were going to be like the first range of spreads.

I fired the second shot, and the numbers were all over the place in a different order /ubbthreads/images/graemlins/frown.gif

So I fired the next three shots and looked at the summaries.

None of the chronos showed the same ES, AV, or SD.

I repeated the same test with the same load from the same box - and none of the chronos showed the same numbers, or even the same patterns - there was a very large randomness to the whole pool of data.

It took a year to figure where the bulk of the errors are coming from, but the point of this is you cannot count on a chrono to detect small differences in BC - you MUST do long range drop tests.

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quarterbore,may have to try the 55 due to your results.I sometimes think the overstabilization is confused by some with shooting a tighter twist than necessary for a particular bullet. I don't think I said the 70 grain had a high ballistic coeff. especially when compared to long range bullets. Just a higher bc than some of the others it is compared to.I too have shot hundreds of coyotes but with a probably much narrower ranges of bullets in 22 and 6mm calibers.A majority of the these coyotes are shot on the run ,so bullet placement is not as consistent as in a calling situation,which adds some variability of results.Most of my years of hunting these plastic tipped bullets were not even offered.It takes alot of shooting with any particular bullet to get a relative idea of its behavior on game.Lots of coincindence and other variables to be sorted thru to arrive at any useful observations..
 
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It takes alot of shooting with any particular bullet to get a relative idea of its behavior on game.Lots of coincindence and other variables to be sorted thru to arrive at any useful observations..



I couldn't agree more... John Barnsness cautions regularly about "examples of one". You shoot a particular bullet at enough stuff... and eventually it will do something you didn't expect it to do. If you do decide to run the 55s... shoot me a PM, I've got a lot of data on them for both the .243 and 6mm Rem. Wait untill you see what a 55 at 4k does to small vermin... it brings a smile to my face just thinking about it!
 
quarter bore ,. Thanks for the response. I looked at point blank ballistics. I believe previous conversations on these ballistics become kind of irrelevant when the Sierra infinity and point blank arrive at such different numbers for the same criteria.
If I load the 55gr , it will be in a 6mm284 for starters . Should make some interesting numbers. .
Conclusions drawn from the coincidence of changing one variable can lead to many false beliefs and practices in all aspects of life. I have seen it so many times and tends to be one of my pet "mini lectures."One can lock himself out of the more correct conclusion for some time.I like the "examples of one" analogy. Will take you up on that pm when I get to loading.thanks
 
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