leftyie---I hook up a bullet alarm clock to my bullets so they dont yawn and go to sleep.
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leftyie---I hook up a bullet alarm clock to my bullets so they dont yawn and go to sleep.
Leftiye
Once again you fail to understand what was said and you have once again ignored the results of the test. The groups of the test do not open up in a linear fashion when velocity is increased and they are targeted at 100 yards. The test that Bass suggests is to test the groups of one load (one velocity/one RPM) that is above the RPM threshold at 3 different ranges. If the groups size increase in a linear fashion then Bass could be correct. If the groups increase larger than linear would suggest then RPM is adversely effecting the. We still haven't answered the question as to RPM above the threshold causing the bullets to "cork screw" (opposite of "going to sleep") in flight.
As to "stupid statement" if you are referring to your own statement you are correct.
Larry Gibson
Larry,
I am glad you are back. Remember I tell you that you test require much shooting? You just say that.
Larry tell me your idea on the sleeping bullet. I explain first. A shooter find his group is much better at a farther distance like 200 or 300 yards then it is at the 100 yard mark. Some claim the bullet has not yet stabilized it self at that close distance and when much farther away it go sleep as they say. My question is if it so unstabilized why do not the rpm just make it much worse? I think to the gyroscope. If you disturb it becomes unstable. If you disturb it enough it go crazy and fly off. But if you disturb it just a little it wobble some then regain it steady spin again. You think maybe this what happens to so called go to sleep bullet?
Ralf
Larry,
"The concept that groups open up linearly" and etc.. Sorry, should have said fact.
Please stop doing that! My comment didn't have anything to do with your test results, it was about what we ALL know happens - not the armchair wisdom, but the observed facts seen by every shooter who has ever shot groups. They DO open up linearly, always have (and hopefully they always will!). I didn't fail to understand anything, neither did you. But you chose to stray from what was said, not me. Excuse me, but as usual. Excuse me again, but "Stupid" is a quote from yourself (don't forget). Not obnoxious, just irritated by your distortions.
How could I fail to understand what was said when I wasn't referring to anything you (or anybody else) said?! Deal with the concepts Larry. Don't quote the liturgy.
So, corkscrewing wouldn't show up as a reduced B.C. number? The boolit IS travleing further isn't it?
Ralf
I am plumb amazed, an intelligent question/explanation in the second paragraph instead of the obnoxiousness as in the first. That is refreshing to say the least!
First if you will read Chapter 1 you will see my inference that the test will take a lot of shooting. I believe I also mentioned the number of rounds fired in the first test. Like I need you to tell me what I already know?
Bullets that "go to sleep" is an interesting subject. I believe it was Elmer Keith reporting on the .333 OKH that first brought this up. I've had several shooters report this to me and attempt to prove it. Seems all had scopes with parallax adjusted farther than 100 yards. When the scopes were parallax adjusted to the proper range the groups were linear as range increased. I though the concept a myth until I first worked with slow twist Palma barrels some years back and using M80 ball ammo (that was required for Palma matches back then).
When using iron sights (no parallax involved) 10 shot groups at 100 yards were very often the same as 10 shot groups at 200 yards. Score books were kept recording each shot. At 600 yards, 800, 900 and 1000 yards the groups increased in a linear fashion (again not exactly linear but with the expected results). The range we were using had target holders at 100 yards and 100 meters or roughly 10 yards between them. One target was placed behind the other at these two ranges. The 100 yard target was just the paper target with no backing to avoid deflecting the bullets as much as possible. The bullet hits in the groups was the same in the two targets. It was observed (confirmed with a retest) that the group of the second target was rotated about 30 degrees clockwise. This gave a real indication that all the bullets were cork screwing in flight. It did not appear that the bullets themselves were unstable and were flying point on. Instead it appears the path of the bullet was one of a cork screw flight instead of a straight line.
Whether the flight of the bullet straightened out (went to sleep) at some range or the cork screw flight simply became smaller than the linear dispersion of the group was not determined in our limited test. It was the consensus of opinion at the time that the bullets still corkscrewed in flight. I tend to agree but am waiting for some definitive testing to prove it one way or the other. I’m not sure the concept is a myth, is real or just a misconception of what is really happening.
Thus it may be the same with cast bullets when they go above their own RPM threshold. They simply fly point on but their flight path begins to cork screw. The higher the RPM above the threshold the larger the corkscrew and the larger group dispersion becomes. I’m not even sure if cast bullets at very high velocity/RPM actually go unstable. I’ve shot some cast bullets of 150-180 gr out of a 10” twist ’06 at 2700-2800 fps that gave 16-30” groups at 100 yards yet the bullet holes were very round giving no indication of tumbling. Granted they pass through the target very quickly but still there was no sign of tumbling.
Those are my ideas or thoughts regarding bullets “going to sleep”.
Larry Gibson
My understanding of corkscrewing is that it is the manifestation of the bullet yawing, and that as the boolit rotates while yawing air pressure deflects the bullet into a spiral path. Not to be argumentative, just that the bullet isn't flying point on when it yaws.
Corkscrewing is also what often happens when a bullet hits an obstruction and is not completely knocked @$$ over teakettle, and the bullets flight then in many cases is an expanding spiral.
Larry,
I have seen this happen. One time reading magazine an article on a new tactical type Weatherby rifle. Very expensive. I surprised the author criticize the rifle. At 100 yards the groups were very bad. He think for that much money this should shoot better. Fortunately he shoot as 300 yards. Then the groups look like good groups for 100 yards. He concludes the bullets going to sleep.
Your paper targets with no backs make me think of story a military veteran tell me. He say if you hang pure silk scarf on clothes line let hang free an shoot at it with any high power rifle that the bullet not put a hole through it because air wave in front of bullet push scarf away. I never try this as I don't believe it. You ever hear such thing?
Ralf
Ralf
Many think of the bullet going to sleep under such circumstances without realising the scope has parallax at shorter ranges. Never heard of the silk scarf trick. Not going to try it either. If it isn't right and I put a hole in a silk scarf the wife would shoot me!
Larry Gibson
I don't believe that for a second unless the wind pushed the bullets back together. Even if the bullets did go to sleep they're still going to follow their 100 yd flight plan and be much worse at 300, that is unless someone's behind a little steering wheel steering them back in.
Maybe not on subject, BUT- - (eh?) I guess it's not such a rare or unusual thing, but I once tried to shoot a group in a plastic bucket with one of my 22-250s. Couldn't make a hole in the plastic. You'd hear the bullet hit, but no hole. I don't think it was just bullet frangibility, but probly also the plastic giving way just a bit at the critical moment. Just FWIW.
Hallo Pat
Good you get involved.
Dynamic stability
A bullet is said to be dynamically stable, if an angle of yaw, induced at the muzzle, is damped out with time, or in other words if the angle of yaw decreases as the bullet travels on. It can be shown that this is true, if the dynamic stability conditionGo to formula is fulfilled.
Pat read this site: http://www.nennstiel-ruprecht.de/bul...ader_stability
Larry
Larry I find good site for you to look at. Please do not tell me you have seen already. Especially read subjects in Contents.
http://www.nennstiel-ruprecht.de/bullfly/index.htm
Ralf
larry that 38gr load is a good choice!!!!
might be a reason on why i shoot 37gr in my 308 after going up to 39gr
it was noticeable at even 50 yds.
i appreciate all the work you are doing, and especially the extra effort with yet another
"test"
hope my 4 yr prediction is false,,,,,,,lol,,,,
Ok, so what did you mean? If you are saying that the groups from normally accurate loads open linearly then we agree. If you are saying that groups from those inaccurate cast bullet loads exceeding the RPM threshold will also open linearly then that assumption is what the test Bass and I are talking about will determine. My experience over shooting such loads at longer range to see if they would "go to sleep" is that groups will increase in size in a very much non-linear fashion as the range is increased. If all that is not what you’re talking about then you've lost me as I then fail to understand your "concept".
Yes, if the bullet is cork screwing the bullet is traveling farther. The measured BCs in fact begin to show smaller BCs as the groups get larger. The BCs are expected to get smaller as velocity is increased but there appears to be a higher rate with the faster twists. If we stretch the cork screw out how much farther the bullet actually travels I do not know. I’m sure there is a math wizard here that could tell us.
Larry Gibson
Thanks. I'm not sure of the necessity to run the test in all 3 twist barrels. I would think that the 28 & 38 gr loads shot in the 10" twist at 50, 100 and 200 yards would be definative enough.
Bass, if your'e reading this why the mention of all 3 barrels for this test?
Larry Gibson