Runout...

[KYpatriot]

Bigjohn what would you say has been helpful in reducing the extreme spread of your ammo for 1000BR? In other words, reducing verticle at 1000?

 

[Unknown]

I think Big John has it right. For some endeavors, the extra work IS worth the effort. When I shoot practical rifle matches where the targets are 2-4 MOA in size, and only go out to 550 yards, it just isn't worth spending twice the time reloading to get ammo that will shoot .3 MOA, because it isn't as important as spending that time practicing my position shooting with an ammo/rifle combo that will consistently shoot 1 MOA.

 

[Clark]

Errors almost never cancel eachother. An error may reduce another error, and may even push past the first error in the opposite direction, if the second error is larger than the first, but to precisely cancel is very unlikely.

OK, there is mostly net cancellation and not perfect cancellation.
But I was correcting someone that was wrong way backwards in as few syllables as possible.
I gave the link for the math of how WE HAVE NET CANCELLATION is adding errors.
The difference between knowing there is NET cancellation and thinking errors just add can be off by a factor of 1000 in amplifier design.

 

[Sniper Uncle]

OK, there is mostly net cancellation and not perfect cancellation.
But I was correcting someone that was wrong way backwards in as few syllables as possible.
I gave the link for the math of how WE HAVE NET CANCELLATION is adding errors.
The difference between knowing there is NET cancellation and thinking errors just add can be off by a factor of 1000 in amplifier design.

You are working in a realm that my bit be practical at times. I can show you real work examples where the practice proves that you are wrong. This is not the place to do so, however, so I won't.
Never the less, even if I were to concede your point, by minimizing each error in ammo making, you minimize the chances of error compounding, or, maximize the chances of errors canceling each other.


Cheers,
Tim
The Right to Keep and Bear Arms Shall NOT be Infringed

 

[M40_A1]

When I shoot practical rifle matches where the targets are 2-4 MOA in size, and only go out to 550 yards, it just isn't worth spending twice the time reloading to get ammo that will shoot .3 MOA, because it isn't as important as spending that time practicing my position shooting with an ammo/rifle combo that will consistently shoot 1 MOA.

You shoot at night?

 

[bigjohn451]

Bigjohn what would you say has been helpful in reducing the extreme spread of your ammo for 1000BR? In other words, reducing verticle at 1000?

I think the single biggest improvement was when I started weight sorting within .1gr and sorting bearing surface to exactly the same length. Unfortunately outside of benchrest where I only need 5 rounds perfectly matched you will go nuts trying to get that fine of consistency.

Just as an example of the precision we need, last match I shot a 3.641" group at 1000 yds... It didn't even win the relay to make the shoot off.

 

[Unknown]

You shoot at night?

The club where I currently shoot is afraid of night matches for now.. I used to belong to a club that had a yearly night match that didn't start until after dark. It was a VERY good way to test out your gear, and see what actually works, and which expensive pieces of kit were complete crap. Some of the lasers and lights weren't worth a damn after about 25 yards, and were only marginal inside 25 yards.

 

[BuzzBoss915]

Just sticking my nose in here for an opinion in regards to the error compounding versus canceling discussion.

I believe this with all my heart. Nothing cancels errors, in loading technique or in shooting technique like an accurate barrel. So, don't waste it. Practice, (if you must) with inferior gear and save that premium barrel for when it matters. BB

 

[Clark]

You are working in a realm that my bit be practical at times. I can show you real work examples where the practice proves that you are wrong. This is not the place to do so, however, so I won't.
Never the less, even if I were to concede your point, by minimizing each error in ammo making, you minimize the chances of error compounding, or, maximize the chances of errors canceling each other.

I am going to state this again.
Multiple error sources do not add linearly.
A common way to add them that matches results in the monte carlo method that is a bunch of math.
It all means that if you are doing a lot of things wrong, stopping doing a few things wrong makes less than proportional improvements.
You try this, you try that, and nothing seems to help.
Most accuracy rituals do nothing.
The ones that help are mostly still down in the monte carlo noise, and don't seem to make a difference when tried individually.

 

[Sniper Uncle]

Clark, you can't have it both ways. You argue that minimizing your errors won't help. You maintain that errors don't build upon each other. You are full of shit. If what you claim is true, then we should just slap our ammo together, and forget about truing actions, and our rifles should shoot one hole groups at 1000 yards, because the errors cancel each other out.
THAT IS BULLSHIT!!!!

 

[Greg Langelius *]

All my barrels have SAAMI chambers (or in the single instance, a no-turn neck), which would seem to me to make concentricity become a lower priority for my ammo making. I once did some testing with a borrowed concentricity gage, and the results either had no relationship with concentricity or were counterintuitive. For my (non-BR) needs that's not especially troubling.

My X-Ring at 1000yd was I MOA (10 1/2"), and I was hitting inside it about 1/3 of my shots, and 95% on average inside the 21" 10-Ring. I was middle of the pack, and since I only compete against myself, that was good enough. If anything, wind conditions made the most crucial difference.

My own needs tended to indicate that neck tension was probably at least as crucial as neck concentricity. I went to some fairly extreme lengths to 'manage' it, but have just recently concluded that while managing it is probably vital, my methods were inconclusive, and maybe even counterproductive. It was an experiment, and a definite proof that all experimental data is valuable, even if it turns out to be negative. At least I gave the proposition plenty of opportunity to work or fail.

There are tradeoffs. Neck concentricity is one I have chosen not to manage. I do so because the amount of detriment my choice has induced still allows my accuracy to fall within my chosen accuracy limits. In return, my ammo making takes less time and money to meet my requirements.

If my requirements change, I will explore different ammo making techniques; but if personal history indicates a direction, I suspect I will be seeking simplicity over complexity.

Greg

 

[Clark]

Clark, you can't have it both ways. You argue that minimizing your errors won't help. You maintain that errors don't build upon each other. You are full of shit. If what you claim is true, then we should just slap our ammo together, and forget about truing actions, and our rifles should shoot one hole groups at 1000 yards, because the errors cancel each other out.
THAT IS BULLSHIT!!!!

Errors don't sum linearly.
They sum in a way better estimated with Monte Carlo method.
We have known about this for a while, 237 years.

Early Recorded History of Monte Carlo
1777 Compte de Buffon: If a needle of length L is thrown at random onto a plane ruled with straight lines a distance d(d > L) apart, then the probability P of the needle intersecting one of those lines is P =2Lπd.
Laplace: This could be used to compute π (inefficiently).
1930s First significant scientific application of MC: Enrico Fermi used it for neutron transport in fissile material.
Segre: “Fermi took great delight in astonishing his Roman colleagues with his ”too-good-to-believe” predictions of experimental results.”
1940s Monte Carlo named by Nicholas Metropolis and Stanislaw Ulam
1953 Algorithm for sampling any probability density Metropolis, Rosenbluth, Rosenbluth, Teller and Teller (generalized by Hastings in 1970)
1962,1974 First QMC calculations, Kalos, and, Kalos, Levesque, Verlet.
1965 First VMC calculations (of liquid He), Bill McMillan.

 

[Sniper Uncle]

Errors don't sum linearly.
They sum in a way better estimated with Monte Carlo method.
We have known about this for a while, 237 years.

Early Recorded History of Monte Carlo
1777 Compte de Buffon: If a needle of length L is thrown at random onto a plane ruled with straight lines a distance d(d > L) apart, then the probability P of the needle intersecting one of those lines is P =2Lπd.
Laplace: This could be used to compute π (inefficiently).
1930s First significant scientific application of MC: Enrico Fermi used it for neutron transport in fissile material.
Segre: “Fermi took great delight in astonishing his Roman colleagues with his ”too-good-to-believe” predictions of experimental results.”
1940s Monte Carlo named by Nicholas Metropolis and Stanislaw Ulam
1953 Algorithm for sampling any probability density Metropolis, Rosenbluth, Rosenbluth, Teller and Teller (generalized by Hastings in 1970)
1962,1974 First QMC calculations, Kalos, and, Kalos, Levesque, Verlet.
1965 First VMC calculations (of liquid He), Bill McMillan.

Clark,
You're going off into the realms of the metaphysical. What may be true in the labs, or under scientific experimentation, may not equate to what is observed in the real world, where most of us are.

Earlier you claimed that most errors cancel each other out, rather than compounding. I call BS, and I can prove it. I own a truck, and I drive it, hauling heavy equipment. I pull trailers that have a "suspended bridge" of 70-78 feet. Several of these trailers have a weak beam. When you load a top heavy load (problem 1), and add the weak beam (problem 2), and then go around a corner (problem 3) where the road is crowned the wrong way (problem 4), those add up to tip the load farther than what you would see if you added the effects of each of those single issues--- I have proven it, time and again. Try another example. I have a drive line vibration. It got much worse a couple weeks ago. Come to find out, the clutch was going bad, and had lost some springs, causing it to be out of balance. The added out of balance really set off the existing driveline vibrations, it did not help to mask it, as you assert it should.

So, you can quote all your Physicists, but in the end, in the real world, we do find that in many cases, problems do indeed compound upon one another. Perhaps we don't see the effects of what you speak because the errors or problems are canceling each other out most of the time, and we don't even know the problems exist. I doubt this is the case, and I know what I have found from years of experience.

So, quote your theories to your heart's content, and I will continue to minimize as many errors as possible. I bet that I will get better real world results.

 

[Clark]

Let's say you have a perfect rifle on a perfect day that always shoots 0 moa 5 shot groups at 100 yards.
But then some guy named random errors comes up to you every time before you take a shot and flips a coin 100 times. For each heads he screws your horizontal adjustment 1 moa right and for each tails he screws 1 moa left.
You may think that he could cause you to get 200 inch groups, but the groups are better than that. You get a 5, 6, two 7s and and 8 inch groups... 6.6" average
You come up with a plan. You will chamfer your flash holes, and that magic enchantment improves the groups 1 moa.
So you chamfer the flash holes, and that random error guy only screws with your horizontal adjustment 99 times.
You think that will get your groups down to 5.6" average, but you are disappointed when there is no change.
So you ask a scientist or engineer what you can do to see the improvement of the flash hole chamfering ritual.
The nerd whips out his calculator and says, if you shoot groups with 12677000000000000000000000000000 shots, you will likely as not to see the improvement from 200" groups down to 198" groups.