243 long range bullet

VLD is Very Low Drag. They are very long, sleek, boattails with a high BC. There are (a few) ULD (Ultra Low Drag) bullets too.

Shooting VLDs (or ULDs) usually means rebarreling to a faster twist, but they give superior long range accuracy (often poorer short range accuracy).
 
Guys, you mean to tell me that I would burn out a .243 barrel in as little as 800 rounds, perhaps less?

This is contrary to some responses I received recently where I asked how to tell if the barrel was "shot out" on a .243 BAR I was looking at (I can't remember which forum I posted under and now can't find the thread..may have been a different website). The consensus at the time was that it would take a couple of thousand rounds to shoot out a barrel and that the probability of a non-competition gun barrel being shot out would likely be nil.

I'm confused.
 
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Hey guys, I know this probably sounds like a stupid question. What does VLD type bullets mean? Thanks.



"V"ery "L"ow "D"rag.

They are designed with a longer than normal length for their weight.

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Guys, you mean to tell me that I would burn out a .243 barrel in as little as 800 rounds, perhaps less?




No, not with a .243. I doubt Jack was shooting a .243 when he was burning barrels at 800 rounds. He shot Highpower competition and was probably shooting a 6XC or 6 X 284. There a very wide variety of 6mm chamberings.
 
The 5 barrels I went through were the standard 243 chamber. They were fast twist barrels to shoot the VLD bullets. I used mostly IMR 4350 but experimented with WW ball powder and slower loads at the shorter stages to try to increase barrel life. There was no noticeable increase in barrel life. The Sierra bullets are good for about 100 rounds more than the Bergers because they have heavier jackets and hold together with a slightly rougher bore. Accuracy was never a problem, all barrels were as acurate as new when retired.

A factory type slower twist barrel will last longer because you can continue to shoot it till either it takes too many fouling shots after cleaning to settle down or accuracy falls off. The slower twists do not blow up bullets until after other problems appear.

Jack
 
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When bullets blow up they come apart. They disintegrate and throw bits and pieces in all directions from the centrifugal force.

Roadrunner is correct that the VLD bullets should be tested at longer range. They almost invariably will shoot a smaller MOA group at 300 than at 100. I have a 22-250AI that will shoot just under 1 MOA groups at 100 yards but shoots close to 1/2 MOA at 300 yards.

I don't think anybody knows the exact reason VLD bullets are like this but it is a very common occurance.

Jack



I'm amazed. The only thing that changes in 800 rounds is barrel wear and yet the bullet's for some reason start comming apart? If the bullet was to come apart, I'd think it would do it in a new barrel! And this deal that ANY bullet shoot's better at 300 yds than at 100 I have never been able to swallow. How does a bullet start out at one minnute of angle at 100 yds then correct it's course and become 1/2 min at 300 yds? I've heard a lot of guy's claim this. I have never heard even one explain it,,,not even in theory! You guy's that make this claim would have us believe that some type of magic happens somewhere between 100 and 300yds and the bullet,,,,GOES TO SLEEP!!!!!!! Walla, back on track. Those rifles must be shooting one hole group's somewhere around 600yds! Then they get off track the other way but probally re-adjust and by 1000yds are right on the money again. Smart bullet's! I'd really love to hear a good explaination for this stuff.
 
DonF,

I don't understand it very well either. But I would tend to agree that it can happen.

I have a remington VSSF 223 (First model) that I believe has a 1 in 12" twist.

I can shoot that gun and get about 1 inch groups and usually a flyer on the 4th shot at 100 yards.

At 100 Yards that would be 1 MOA.


But, if I take that gun and shoot a 200 yard target, it will always stay in 1" and the impact will be horizontal. so I usually have all 5 shots dead center vertially, but the string covers from left to right 1"

At 200 yards, that would be 1/2 MOA.

All of this is with the cheapo federal bulk pack 223 / 55 Gr.

I shoot at long distances with this gun just for fun and practice and I do believe that it gets more accurate at longer range. I have shot at targets out to 880 yards and went 10 for 10 on a 1 foot target. I know that a 1 foot target is more than MOA for this distance, but 12" is still kill zone for most animals that I hunt.

With that said, I wouldn't shoot game that far with that gun. My limit for power would stop around 250-300 yards.

Needless to say, I'm keeping that gun.
 
The bullets blowing up is very easy to see if you look at the bore through a borescope. The bore get rough, it looks like alligator hide, the roughness damages the jacket till it can't withstand the centrifugal forces. Fast twist barrels are spinning bullets at 300,000+/- RPM.

Believe what you want about VLD bullets shooting smaller MOA at 300 than 100. It is just the experience of a couple thousand long range competition target shooters. 300 yards is about as small MOA as it gets though, it does not keep getting smaller beyond that but opens up in the normal manner.

Jack
 
"And this deal that ANY bullet shoot's better at 300 yds than at 100 I have never been able to swallow. How does a bullet start out at one minnute of angle at 100 yds then correct it's course and become 1/2 min at 300 yds? I've heard a lot of guy's claim this. I have never heard even one explain it,,,not even in theory!"

Here's a piece I wrote on the matter...

http://practicalrifler.6.forumer.com/viewtopic.php?t=4

And the very long (but very enlightening) thread I began at Benchrest Central some time back... read all the responses and see if things begin to make more sense. http://www.benchrest.com/forums/showthread.php?t=10744&highlight=attention+concentricity

In short, Jack is right (as he generally is) /ubbthreads/images/graemlins/smile.gif --tightening MOA's do happen. We now believe that we know why...

Dan
 
That acro is for very low drag, referring to the bc of the bullet...ie a 120 gr speer bt in .257 has a bc of .435, but a 115 berger is almost .550. It takes a faster twist to stabilize these pills.
 
Worked for the Air Force at the USAF Marksmanship School, Lackland AFB, San Antonio, TX, and at Kirtland AFB, Albuquerque, NM, in research and development using even bigger "bullets."
Yes, bullets, missles, rockets, etc., do, "go to sleep" at longer than normal ranges. We tested these theories even with electro-magnetic rail guns for super velocities. High speed photography, an extremely difficult process for the velocities we were achieving, showed the results. Very interesting.
On the .243/6mm, we tested these for 1,000yd matches and for reduced recoil in 300meter free-rifle competition. Our initial assumptions from almost 30 years ago were shot down like Snoopy vs the Red Baron. After that, we tested all long range stuff at a minimum of 200yds...and usually at 300yds (it was great at Lackland to have basic trainees as target pullers so we didn't have to continually walk back and forth /ubbthreads/images/graemlins/wink.gif).
Some conclusions for all calibers and match accuracy:
The 6mm Rem gave longer throat life than did the .243 due to length of neck protecting against powder blasting.
Ackley Improved shaped cases with sufficiently longer necks provided the best throat protection.
Bullets of increased length, i.e. VLD, required faster twists, sometimes as much as 1-7, but usually 1-8.
Cleaning effectively and carefully assisted in promoting barrel life.
Barrels could continue with good accuracy by seating bullets out longer and longer until cases couldn't hold the bullet in the proper manner.
Setting barrels back far enough to overcome throat wear and rechambering usually returned the match accuracy, but usually that was gone after about 1500rds. (I used some of the barrels we were discarding for hunting and varminting and had sufficient accuracy for awhile.)
We also tested 6.5-08, 6.5-.284, 6.5 Weatherby/Wright/Hoyer, 6.5-06, 7mm wildcats, and .30 wildcats trying to find out anything we could. Most of this info has been published, but some only in scientific journals.
 
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Those are intresting articles but I've a question. Let's assume that the bullet does wabble down the barrel. Passing thru the barrel wouldn't the barrel actually re-form the bullet and build in the wobble permently? How does that get corrected in flight? I can buy that the bullet might wobble some degree but as the bullet stabilizes, it would have to do it at the same point in flight every time, or very very closely. If the bullet didn't stablize or left the barrel to under stablized, wouldn't the effect be noticed with key holeing? Has anyone tried shooting these bullet's that seem to correct themselves from machine rest's at both ranges?

This whole idea of bullet's going to sleep seem's to be based in theory. I suspect that at some point the bullet does stablize, otherwise at some point the bullet would have to tumble. What I have a hard time with is that for a rifle to shoot,ie: a minute of angle at 100 yds and then 1/2 minute at 300yds, somewhere along the line the bullet would HAVE to correct it's course on it's own. How does that happen? Could it not be that some people take greater effort in sighting at longer ranges? At whichever direction the center of axsis is pointing as the bullet leaves the barrel, the bullet would have to travel in a srtaight line on that angle until it stabilized then flew straight on that axsis.

If the bullet is cocked as it enters the chamber then it would seem to me that the barrel will re-form the bullet changing that axsis. If the bullet does not enter at exactly the same point in it's wobble and with the same pressure EVERY TIME, then each would be re-formed to something new individually each time. The barrel is much harder than the bullet and one must give! Isn't that why the lands are ingraved on the bullet?
 
Think of a toy top. When you pull the string setting it to spinning, there is an initial wobble, then the top settles down to continue on a more or less stable spin.
You are right in that, if the bullet is not set up to enter the rifling the same way each time, of course there will be an effect on accuracy. This is why most benchresters seat their bullets a little long, to touch or be engraved by the rifling. Smallbore shooters also do this by making the chambers tight.
As far as different points for the bullet to stabilize or "go to sleep," most benchresters use the 1-14 twist for 52/55gr bullets because the bullets will stabilize at a shorter distance (before 100yds) with the slower twist. Some have even tried 1-14.5" and 1-15" twists to take advantage of this. The theory of using minimum twist holds up to just about 200yds, then accuracy starts to deteriorate.
Well then, what if we increase the twist? The bullet hasn't reached maximum stability at 100yds, making for some strange holes in a target if we look at them with a magnifying glass. Measuring the group is difficult. If we measure the 100yd group, then a 300yd group, we find, low and behold, it seems as if the bullet has corrected itself and is now making smaller MOA groups (remember 1 MOA at 100yds is a little over 1", 2" at 200yds, 3" at 300yds), BUT, the group is larger. Looking at the bullet holes with the magnifying glass also shows rounder holes.
 
If a bullet is wobbling (for whatever reason) it cannot fly in a straight line. As its tip oscillates around in the air, it will actually move in a cork-screw like pattern through the air--this according to well trained individuals who have studied and opined on the flight of bullets.

Put another way, if you hold a model rocket in front of a fan, and tilt its point slightly left and right, you can feel the wind push it even farther aside. If the rocket was spinning, it would try (like a gyroscope does) to correct its axis, resisting the wind. A wobbling bullet does this too. As the wobbling bullet's axis is challenged by the oncoming wind, the bullet's spin presses it back on axis--but it over-corrects slightly in the opposite direction. A cork-screw pattern is then realized. The bullet may go from 1 o'clock (outside the line of the perfect bullet) to 7 o'clock, then from 3 o'clock to 9 o'clock, then 11 o'clock to 5 o'clock, as it tries to align its path with the spin axis--which is also the path of a perfect bullet which did not wobble.

If that cork-screw pattern is, say, 1" in diameter at 100 yards, that's probably as large as that pattern is going to get; as the bullet settles down, this cork-screw pattern will get smaller and smaller, until the bullet eventually assumes a path very similar to a bullet which did not wobble.

So, a 1" cork-screw pattern at 100 yards may not grow any larger (and will in all probability get smaller) as the bullet reaches the 300 yard point.

It's true that there can be other explanations for why some might see groups tighten at longer ranges. Scope parallax is one. As you mention, some folks might concentrate harder on the longer range group, or perhaps even concentrate less hard since they don't expect the group to be so great--which relaxes them and therefore improves consistency.

But even in light of the other reasons why we see tightening MOA's, the cork-screwing pattern of a wobbling bullet is likely the culprit most of the time--in my opinion.

Think of the cork-screwing bullet as "circling around" the path of the perfect, stable bullet. It's a half inch out at 2 o'clock when the bullet is at 50 yards, then it's a half inch out at 8 o'clock when the bullet reaches 100 yards. This wobbling bullet circles the path of the perfect bullet--until the wobbling bullet settles down, then it assumes a path somewhere within an inch or so of the perfect bullet's path.

I agree that the bullet which enters the throat off axis will be engraved in a less than concentric manner, but we're only talking a couple thousandths of an inch at most. Once it exits the muzzle, it will indeed have a slightly out of kilter rifling pattern about its girth, but this pattern should be well balanced enough that the bullet doesn't destabilize and actually tumble. The very slight amount of axis diversion would cause a bit of tip oscillation (which causes bullet yaw, and the cork-screw pattern) but nothing worse.

This is my current understanding of the matter, but I'll always welcome differing points of view.

Dan
 
Well Dan and Prof242, I think I'm getting what you are saying now. Going to try that "OCW" program soon as the wind quit's here.

First explanation's I've heard that make any sense. Sound's to me like the yaw is different than we've been led to believe for a long time. And "go to sleep" is just a spiffy name for stabilizing.

Dan, if I understand, the "OCW" will expose itself by being the mid load and being closest to POI? I am not sure how you trianglate it tho. Used to be able with a radar scope and an aircraft but it's been a long time. I'll work on it. Ah, got it! Draw a line between each hole and POI is the center of the triangle.
 


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