Have you considered packaging up your rifle and shipping it to Bryan? You may have all the parts and pieces that self-assemble into a functional watch.
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Applied Ballistics 'Shoot Thru Target' Challenge
- Thread starter BryanLitz
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Have you considered packaging up your rifle and shipping it to Bryan? You may have all the parts and pieces that self-assemble into a functional watch.
Danehunter
Well-Known Member
PHYSICAL GIVENS:
1. Bullets leaving the muzzle are spinning at their maximum rate and slow thereafter.
2. With no wind horizontal deflection occurs due to spin, right or left.
3. Once spin drift is accounted for all other deflection will be vertical due to the effects of atmosphere and gravity until transonic speed is reached, when yaw can occur due to instability.
Are these the BASIC physical factors on external ballistics? (indoor range with temperature and humidity control)
If so then optics remains as the chief variable.
1. Bullets leaving the muzzle are spinning at their maximum rate and slow thereafter.
2. With no wind horizontal deflection occurs due to spin, right or left.
3. Once spin drift is accounted for all other deflection will be vertical due to the effects of atmosphere and gravity until transonic speed is reached, when yaw can occur due to instability.
Are these the BASIC physical factors on external ballistics? (indoor range with temperature and humidity control)
If so then optics remains as the chief variable.
Again we come back to theory versus practice.
In terms of what one shooter might observe at a particular outdoor range will not necessarily be the same at another range, let alone at a different target distance.
Slap a firearm of any sorts into a machine rest and take away the human elements (especially the optics) and test fire in a controlled environment. Again factory ammunition is tested worldwide using this method and I've yet to read any reports describing reduced group size with distance. If the firearms/ammunition manufacturers did find a repeatable combination, then their marketing departments would be the first to shove it down our throats as the next big thing, in an attempt to differentiate themselves from their competitors.
In practice, at an outdoor range with certain conditions I certainly would not say that the phenomenon is not possible, just not very probably.
Please excuse me for indulging in some lateral thinking again. Next time you're visiting a natural flowing water course, push a buoyant mass into a relatively large open section upstream from a narrow converging section, maybe even rapids but no major obstructions given the size of your chosen buoyant mass. Note where the mass finishes after the narrows. Repeat the step again with same mass, but go further upstream. You can also try pushing the mass out into the open section with a variable amount of force. Relatively speaking, the mass will go into and out of the narrows with the same amount of "accuracy". Effectively there is a force that is funnelling the mass through the same point/window each time.
Now I won't be so bold as to try and tell you these masses, forces and velocities are proportional to those experienced by a supersonic projectile under the influence of wind on the way to the target. That does not mean though that the concept can not apply and some shooters have effectively 'measured' this at their range. Effectively there could be a 'window' (2-D planar) or tunnel (3-D) that exists under certain conditions wind or even light conditions for a period of time, that enhances accuracy between the shooter and the target. Effectively a shooter's aiming errors and/or load group size dispersion is reduced significantly enough to produce a measurable result. The conditions after the window or tunnel would not be variable or have no significant influence on the course of the projectile. Ideally a tunnel would exist from your eye to the target, large enough to accommodate your barrel and projectile trajectory.
Yes I threw in light also, because although that target physically exists in time and space, that visible part of the electromagnetic spectrum needs to pass through a variable (density) media, ground-level atmosphere. Significant changes in the density of that media and light will bend. It may not bend enough to see around corners, but the mirage effect from a temperature inversion can be significant when it occurs at the target and doesn't include the shooter's position.
Must think about shorter posts, but it would be a lot easier if I just knew the exact answer instead of all this hypothesising
In terms of what one shooter might observe at a particular outdoor range will not necessarily be the same at another range, let alone at a different target distance.
Slap a firearm of any sorts into a machine rest and take away the human elements (especially the optics) and test fire in a controlled environment. Again factory ammunition is tested worldwide using this method and I've yet to read any reports describing reduced group size with distance. If the firearms/ammunition manufacturers did find a repeatable combination, then their marketing departments would be the first to shove it down our throats as the next big thing, in an attempt to differentiate themselves from their competitors.
In practice, at an outdoor range with certain conditions I certainly would not say that the phenomenon is not possible, just not very probably.
Please excuse me for indulging in some lateral thinking again. Next time you're visiting a natural flowing water course, push a buoyant mass into a relatively large open section upstream from a narrow converging section, maybe even rapids but no major obstructions given the size of your chosen buoyant mass. Note where the mass finishes after the narrows. Repeat the step again with same mass, but go further upstream. You can also try pushing the mass out into the open section with a variable amount of force. Relatively speaking, the mass will go into and out of the narrows with the same amount of "accuracy". Effectively there is a force that is funnelling the mass through the same point/window each time.
Now I won't be so bold as to try and tell you these masses, forces and velocities are proportional to those experienced by a supersonic projectile under the influence of wind on the way to the target. That does not mean though that the concept can not apply and some shooters have effectively 'measured' this at their range. Effectively there could be a 'window' (2-D planar) or tunnel (3-D) that exists under certain conditions wind or even light conditions for a period of time, that enhances accuracy between the shooter and the target. Effectively a shooter's aiming errors and/or load group size dispersion is reduced significantly enough to produce a measurable result. The conditions after the window or tunnel would not be variable or have no significant influence on the course of the projectile. Ideally a tunnel would exist from your eye to the target, large enough to accommodate your barrel and projectile trajectory.
Yes I threw in light also, because although that target physically exists in time and space, that visible part of the electromagnetic spectrum needs to pass through a variable (density) media, ground-level atmosphere. Significant changes in the density of that media and light will bend. It may not bend enough to see around corners, but the mirage effect from a temperature inversion can be significant when it occurs at the target and doesn't include the shooter's position.
Must think about shorter posts, but it would be a lot easier if I just knew the exact answer instead of all this hypothesising
Can an anomaly of the muzzle crown / bore / rifling flip certain bullets significantly sideways as the bullet exits the barrel ? Visualizing muzzle blast catching the same side of a boat tail and crossing that bullet up good but spin eventually puts it back to sleep??
Harold Vaughn did some interesting studies on muzzle blast effects in his book " Rifle accuracy Facts"
I have not read the book, thanks, another to read! I did find this study, it breaks the muzzle blast effect down in different ways , it is a problem but not on the scale we are looking at here. Its just another cyclic bullet path that straightens up. But this study does not get in to how much worse it can get if some imperfection at the end of the barrel deflects an unusual amount of blast on one side of the boat tail. A different dispersion would happen if the imperfection was in a run of bullets just the rear, boat tail or not.
http://www.dtic.mil/dtic/tr/fulltext/u2/a066121.pdf
http://www.dtic.mil/dtic/tr/fulltext/u2/a066121.pdf
Danehunter
Well-Known Member
In my last post I should have stated another "GIVEN", namely that the rifle was zeroed at 100 yds. with a load that gives sub MOA accuracy.
My Brownning A-Bolt has a BOSS muzzle brake that has a micrometer style adjustment for zeroing factory loads by adjusting the barrel harmonics. It works.
This is so the bullets always leave the muzzle at the same point (say at 2 o'clock) in the barrel's harmonic movement.
So, yes, we all know barrel harmonics affects dispersion in every vertical and horizontal plane. But once that is minimized to maybe 1/2 MOA we can look to other factors affecting bullet dispersion.
My Brownning A-Bolt has a BOSS muzzle brake that has a micrometer style adjustment for zeroing factory loads by adjusting the barrel harmonics. It works.
This is so the bullets always leave the muzzle at the same point (say at 2 o'clock) in the barrel's harmonic movement.
So, yes, we all know barrel harmonics affects dispersion in every vertical and horizontal plane. But once that is minimized to maybe 1/2 MOA we can look to other factors affecting bullet dispersion.
Punisher,
Are you interested in a paid trip to my lab in Michigan to demonstrate this on the shoot thru target? Let me know when to expect you and I'll pay your way.
Litehiker,
We agree that barrel harmonics can affect POI and group size. However I'm unclear if you're saying that your rifle can shoot smaller MOA at range in response to this tuning. If this is what you're saying, then I'd like to pay your way to the lab to demonstrate this effect. To be clear, we're looking for group convergence in all directions, not just vertical. Vertical group convergence is known to be possible thru the mechanism of positive compensation. We're looking for an example of a rifle that consistently shoots smaller MOA groups in both vertical and horizontal at longer ranges.
Guys,
This thread/challenge is intended to explore the question of IF group convergence happens with LIVE FIRE experiments. I've presented results from several of my tests, and Canadian has posted the results of his test. Other than that and the information presented on past live fire experiments, most of the discussion has been off the intended topic.
I'm open to discussing any means of demonstrating group convergence on my shoot thru target, or someone elses. The theory is interesting, but as far as this thread goes, it's irrelevant until convergence is directly demonstrated as being repeatable.
Maybe I should consider paying a cash reward for anyone who can successfully demonstrate convergence...? That may help keep the discussion focused.
-Bryan
I am absolutely as adamant as you are to figure out what the root cause for reports of convergence is. I will PM you later with what I have documented already and if it is the type of data that you are looking for, then I will come up there and probably have a really great time learning and developing really complicated mathematical expressions... Which is kind of another hobby of mine.
Danehunter
Well-Known Member
Bryan,
Absolutely I'm saying that the Browning BOSS adjustable brake does tighten groups, especially with factory ammo.
That's why Browning offered it, first on their BAR auto rifle and then on A-Bolt rifles.
BUT... I have never seen an example of "convergence" of groups at distances beyond 100 yards and up to 400 yards when using my .300 Win mag A-Bolt. This rifle has two stocks, the original plastic stock and a Browning laminated thumbhole stock, both are custom action and pillar bedded.
Both stocks shoot to the same point of aim when action bolts are torqued to the same inch lbs.
Absolutely I'm saying that the Browning BOSS adjustable brake does tighten groups, especially with factory ammo.
That's why Browning offered it, first on their BAR auto rifle and then on A-Bolt rifles.
BUT... I have never seen an example of "convergence" of groups at distances beyond 100 yards and up to 400 yards when using my .300 Win mag A-Bolt. This rifle has two stocks, the original plastic stock and a Browning laminated thumbhole stock, both are custom action and pillar bedded.
Both stocks shoot to the same point of aim when action bolts are torqued to the same inch lbs.
Hi Brian,
I bumped into an article on 6mmBR's website:
"While Matt says his bullets don't "go to sleep" for a couple hundred yards, this gun can still shoot 1/4" groups at 100 yards and hold that accuracy much, much farther. Matt reports, "my best-ever group was five shots in .397" at 400 yards. Yep, I got lucky with the conditions, but this is a very accurate rifle."
link: .243 Ackley Improved Match 1000 yard Varmint Rifle with Farley Action & Lilja Barrel
I have read and heard so many shooters tell me that their bullets don't go to sleep or settle down for a few hundred yards. There might be some believers on this site that might take your challenge.
Ross
I bumped into an article on 6mmBR's website:
"While Matt says his bullets don't "go to sleep" for a couple hundred yards, this gun can still shoot 1/4" groups at 100 yards and hold that accuracy much, much farther. Matt reports, "my best-ever group was five shots in .397" at 400 yards. Yep, I got lucky with the conditions, but this is a very accurate rifle."
link: .243 Ackley Improved Match 1000 yard Varmint Rifle with Farley Action & Lilja Barrel
I have read and heard so many shooters tell me that their bullets don't go to sleep or settle down for a few hundred yards. There might be some believers on this site that might take your challenge.
Ross
I am new to this site and have just picked up on Bryan's rifle printing perfect holes at 100yds but tipping at 300yds.
All my 6BRs do this, and indeed all shooters I have marked for firing 6BRs with 1:8 twists at 300m show yawing bullet holes. Accuracy is unaffected. In my case 95gr Bergers have an SG of 1.8. Never have I seen a .308 show any tipping, even when marginally stabilised with a 1:14 twist and 167 Scenars.
Why is this so?
Austen.
All my 6BRs do this, and indeed all shooters I have marked for firing 6BRs with 1:8 twists at 300m show yawing bullet holes. Accuracy is unaffected. In my case 95gr Bergers have an SG of 1.8. Never have I seen a .308 show any tipping, even when marginally stabilised with a 1:14 twist and 167 Scenars.
Why is this so?
Austen.
Danehunter
Well-Known Member
Austin, I think Bryan would be VERY interested in testing your 6BR.
