What causes flyers

[tuj]

This is some data I found, there are lots of other examples.

Custom Ruger Charger, 10" KIDD Bull Barrel
Custom Ruger 10/22T, 18" KIDD Lightweight Barrel
Custom Ruger-Nordic 10/22, 20" KIDD Bull Barrel
Custom Ruger 77/22, 20" Clark Custom Guns Bull Barrel

10" Ruger Charger (KIDD Barrel)
40gr. SK Standard Velocity Hollow Point
Date = 4-17-12
Temperature = 61 degrees
Average Velocity : 986 FPS
Extreme Spread : 25
Standard Deviation : 6.93

10" Ruger Charger (KIDD Barrel)
40gr. Wolf Match Target
Date = 4-17-12
Temperature = 61 degrees
Average Velocity : 939 FPS
Extreme Spread : 135
Standard Deviation : 13.49

18" Ruger 10/22T (KIDD Barrel)
40gr. SK Standard Velocity Hollow Point
Date = 4-17-12
Temperature = 61 degrees
Average Velocity : 1066 FPS
Extreme Spread : 43
Standard Deviation : 6.93

18" Ruger 10/22T (KIDD Barrel)
40gr. Wolf Match Target
Date = 4-17-12
Temperature = 61 degrees
Average Velocity : 1025 FPS
Extreme Spread : 79
Standard Deviation : 10.44

20" Ruger - Nordic 10/22 (KIDD Barrel)
40gr. SK Standard Velocity Hollow Point
Date = 4-17-12
Temperature = 61 degrees
Average Velocity : 1018 FPS
Extreme Spread : 49
Standard Deviation : 8.37

20" Ruger - Nordic 10/22 (KIDD Barrel)
40gr. Wolf Match Target
Date = 4-17-12
Temperature = 61 degrees
Average Velocity : 1002 FPS
Extreme Spread : 47
Standard Deviation : 9.85

20" Ruger 77/22 (Clark Barrel)
40gr. SK Standard Velocity Hollow Point
Date = 4-17-12
Temperature = 61 degrees
Average Velocity : 1014 FPS
Extreme Spread : 29
Standard Deviation : 7.28

20" Ruger 77/22 (Clark Barrel)
40gr. Wolf Match Target
Date = 4-17-12
Temperature = 61 degrees
Average Velocity : 1003 FPS
Extreme Spread : 67
Standard Deviation : 10.58

The best standard deviation on this 22lr ammo selection was around 7fps. The velocity was 1066 = 0.65%. The worst was 1.43%. The 17hmr that varmintAl tested equals 1.32%. So yeah, the fact that CCI makes all the ammo is a problem, but let's be honest, its not THAT bad for factory rimfire ammo. Then consider that 22lr has been around for a lot longer than 17hmr and there is competition in the 22lr market.

My cheapo Savage 17hmr will *on average* shoot 1MOA at 100 yards or better across multiple boxes of ammo. That's better than a lot of AR's with NATO ammo.

 

[12many]

First time was a pretty solid wood table and the second a less stable portable table. Both were stable, but had some movement if weight was moved. The stock was supported by my shoulder and a bag. The front by a steel tripod base with threaded adjustment post front support (I am sure that is a word for this device, but I don't know it).

Next time I am going to shoot at the area of the range with very solid long benches that are covered and ask some of the other more experienced target shoots to put some groups on the target using my ammo and gun. They are better shooters than me. I don't image they would mind helping me out in that way. Worst that would happen is they say no.

 

[taliv]

just putting some quick numbers in jbm using default values and 168smk at 2600 fps and 2635 fps (note this is only 35 fps ES, not 35 SD that you're talking about) gives at 3.1" difference in elevation at 600 yards and 15.6" difference at 1000 yards. now, the x ring on an f-class center is 3" at 600 and 5" at 1000. so if you aim perfectly at the center, your 35 fps higher round will be half an inch into the 7 ring at a k.

X ring 5.0" diameter
10 ring 10.0"
9 ring 20.0"
8 ring 30"
7 ring 44"
6 ring 60"
5 area 6 foot square

but then... you're not talking about ES, you're saying 35 fps SD is ok. well, what that really says is that 95.45% of your rounds will be +/- 2 SD which is a 140 fps range. so in a 60 round match you will probably have 2 rounds more than 140 fps apart, which will give you almost 59" of vertical on a target that's only 60" diameter.

the SD for good handloads is about 10-12 for most uses, but for f-class, Litz says 5 fps, and you can see why.

to be fair, instead of using a 308 as an example, using a cheater caliber like 6XC, the 140 fps difference is only 27.3" at 1000. and the 20 fps difference you'd get from a 5 SD is only 4.1" at 1000.

nevertheless, the only way velocity doesn't make any difference at all is at very short ranges.

as far as your 'flyers' MV probably plays a small part of that. if it didn't, people wouldn't do ladder/OCW testing.

 

[denton]

1. Estimating standard deviation is not as easy as estimating a mean (average). If you have a sample size of 20-25, you can get a pretty reliable estimate of a mean. This is not so for a standard deviation. Large samples are required for reliable estimates. An estimate of SD based on a sample of 5-10 is not precise. Just for grins, I electronically generated a sample of 5 with a standard deviation of 27. The Confidence Interval for the estimate is 16.5 to 79, meaning that if I repeated my sample over and over again, with no change in the process, I'd frequently get values as low as 16.5 and as high as 79. Moral of the story: Unless someone has a lot of data, don't believe their estimate of standard deviation.

2. Variation does not add linearly. You cannot simply add the effect of the variation in muzzle velocity to your other sources of variation. If you're shooting at 500 yards with a 1 MOA rifle, and doing everything perfectly in calm air, you'll have roughly 5 inch groups at 500 yards. If the variation from muzzle velocity is another 2 inches, you will barely be able to detect that your groups are stretched vertically. Your normal random variation from other causes plus the MV variation will vertically stretch your groups only about .4".

 

[taliv]

1. the SD of a group is helpful in describing the distribution. i believe while your comments are generally true, they are misleading. I have never had a load that shoots a 10 SD one day shoot 50 SD the next, or even 20 SD. It just does not happen. Given fairly similar conditions, my SDs for a particular load will consistently be between 8-12 SD. Under different conditions, my SDs for the same load will consistently be under 5 SD, despite relatively low populations of under 10 rounds.

2, with sufficient number of rounds, you pretty much can. with low number of rounds, sure, it is likely that a factor causing a shot to go high will be offset by another factor that causes a shot to go low.

you are really taking an unusual and unproductive approach. you are saying "my rifle is 1 MOA, so MV is in the noise and unimportant."

I am saying " you have no idea what your rifle is capable of, because MV is one of the many variables contributing to your 1 MOA shooting. isolate it and eliminate it, and then isolate and eliminate the next variable. eventually you may find your rifle is a .1 MOA but you will never know as long as your MV is giving you 59" spreads at 1k."

 

[denton]

Taliv my friend, please trust me on this. It is as I have said.

I have never had a load that shoots a 10 SD one day shoot 50 SD the next, or even 20 SD. It just does not happen. Given fairly similar conditions, my SDs for a particular load will consistently be between 8-12 SD. Under different conditions, my SDs for the same load will consistently be under 5 SD, despite relatively low populations of under 10 rounds.

When you shoot and measure 5, or 10, or some other number of cartridges out of a lot, you are taking a sample. There is a rather great and well established body of knowledge regarding the behavior of samples. The uncertainty in the estimate of a standard deviation is well understood, and it is as I have said.

with sufficient number of rounds, you pretty much can

Regardless of how many samples you take, standard deviations add by the square root of the sum of the squares.

you are saying "my rifle is 1 MOA, so MV is in the noise and unimportant

In most cases, that is exactly a true statement. For 1 MOA rifles and typical commercial ammunition, the variation in MV is unimportant in group size. Surprising, isn't it? I did have an article in Varmint Hunter a few years ago that explored the topic.

One mathematical consequence of the fact that standard deviations add by the square root of the sum of the squares is that the largest single source of variation dominates the total variation. So you can fiddle all you want with the minor sources of variation and produce practically no result. Only when you reduce the largest source of variation will you see real change. So, in the case of my 223, I got 5/8" groups whether I was using ammunition with an MV standard deviation of 8-10 FPS or ammunition with 35 FPS SD, just as the math said I should.

Here's a little simpler case to think about that illustrates the point.

When I started out reloading, and before most of my stats career, I was being very careful and individually hand weighing powder charges for that same old 223. I thought it was helping some. It was not.

For that cartridge, a grain of powder is roughly 100 FPS. I ran the stats on my powder dispenser, and found that it had an SD of .11 grain, and assumed that if my charges were all perfectly identical, I'd have a baseline MV SD of 25 FPS from differences in neck tension, bullet weight, case capacity, etc.

An SD of .11 grain of powder translates to an MV SD of 11 FPS. That sounds like it's big enough to worry about if your baseline is 25 FPS. You would naturally think that the two together would produce an MV SD of 36 FPS. But here's how the math actually works out:

Total MV SD = square root (25^2 + 11^2) = 27.31 FPS

So switching from a perfect powder dispensing system to the one I own increases your MV SD from 25 to 27.31. In other words, no real gain on the play. And it's worse than that because even a pretty good scale will have almost as much random variation as that powder measure.

The same thing applies to bullet holes in two dimensions, i.e., group size. If your rifle is free from "special cause" such as barrel rubs, loose sights, and shooter flinch, so that we are looking at a pure random process, then an SD of 35 FPS is not a significant source of larger group size in most rifles.

Now if you have a 1/2 MOA rifle and are shooting at 1,000 yards with perfectly calm air and no mirage, the difference starts to be important.

 

[Hardtarget]

I've been seeing this for a while now. After i got my AR it seemed like I should try to find ammo it liked. I got all the components together. I checked for load info from books, web sites, and the brain trust here at High Road.
I did my careful reloading effort (most of you would laugh) and then a range trip.
no matter what I did...there were the fliers.

I just mark it up to "shooter error". Then I quit worrying about it. Its just gonna happen.

Mark

 

[Walkalong]

I have never had a load that shoots a 10 SD one day shoot 50 SD the next,

I haven't either. Taking small samples will definitely vary with the same load, but in the end it will all add up to what you really have, and would have shown with a large enough sample. We have to take small samples with a grain of salt, but they are useful, and I have never seen such a large difference in SD for the same load when taking small samples at different times. Maybe I haven't done it enough, but I have done it a lot.

The what exactly do you gain and is it important/worth it is right on target. Plinking at 25 yards? Shooting Benchrest at 100/200 yards. Shooting at 1000 yards? The answer for some things is different for all three.

 

[Cee Zee]

Most "fliers" are just bad shots when the load and equipment aren't at fault.

Fliers do happen of course, but not often when using top class equipment and bullets properly loaded.

I wouldn't disagree with that one bit. But the question was about flyers and true flyers aren't caused by jerking the trigger or pushing the rifle or anything except bad ammo or equipment. Again a person needs to learn to recognize when they make a mistake. That's why being a good shooter takes lots and lots of practice. That's how you learn when you're the problem or something else is the problem. Without that knowledge you are never going to get better as a shooter.

I don't think most of us can ever completely overcome bad trigger pulls but there are ways to work on it. Still, especially with rimfire, you will find some flyers that are obviously the fault of the ammo. Just going through a brick of rimfire ammo and looking for poorly made cartridges will prove that they are not all created equal. Of course the pros sort their ammo before they shoot in competitions. Not only do they check for obvious problems with cartridges but they check weight, size and other things. It is MUCH easier to control a center fire weapon of course. But that's when you roll your own. Using factory ammo you will still see bad rounds and even bad batches.

I'm not knocking your point. Clearly it is the place to start for everyone. At the same time with rimfire I would go through the rounds before I tried to gauge the accuracy of a rifle. Too many of them are out of round, dented and not seated correctly.

I know you know these things. Mostly I'm just making the point that bad shots not being flyers doesn't really address true flyers. Again if a person can't tell the difference then they need to practice a LOT more.

Making a rifle shoot it's best is a long process and it's a process that must be maintained even after you work out the bugs. New ones will always pop up. Scopes get knocked off alignment, burrs can develop in chambers and barrels, crud can accumulate n a gun, etc. etc. etc.. It's all part of becoming a truly good shooter.

 

[taliv]

denton, i think we're just talking past each other and using statistics very differently.
i think you are sampling your powder measure and then making an assumption about your MV variance being based on different amounts of powder in the case.

that isn't what i'm doing at all. i know exactly how much powder is in my cases because i weigh every one to +/-.01g which is essentially one kernel of most extruded rifle powders. i've eliminated that variable, so i believe i can see changes in MV from other sources, like how fouled my barrel is, and how much neck tension i put on the bullet.

statements like this make no sense to me

An SD of .11 grain of powder translates to an MV SD of 11 FPS.

because it's not my experience at all. when i want to test this, i weigh out exact charges for a range and can say with reasonable confidence that an increase of .10 grains yields an increase of x FPS. I find as i work up over a few grains that is not linear and the closer you get to max the more the FPS increases.

 

[Walkalong]

Mostly I'm just making the point that bad shots not being flyers doesn't really address true flyers. Again if a person can't tell the difference then they need to practice a LOT more.

I totally agree. The part about being able to tell if it was me or something else was the hardest to learn. That takes shooting a lot (Experience), and nothing else can substitute for it.

There were plenty of days I told someone that no, the rifle is trying to shoot, I just keep messing it up. It's all me.

The time my scope got loose on my bench gun I blamed myself for the first bad group, but on the second bad group I was suspecting a problem, then on the third it was obvious to me it was a problem with equipment. Fixed the problem and bingo, started shooting little groups again. Too late for that aggregate, but hey.

So I guess my point was so many people call bad shots fliers, when they aren't.

True fliers are hard to tell sometimes. I don't believe most of us can always tell. Some of the best shooters are pretty dang good at it though.

 

[Cee Zee]

The time my scope got loose on my bench gun I blamed myself for the first bad group, but on the second bad group I was suspecting a problem, then on the third it was obvious to me it was a problem with equipment. Fixed the problem and bingo, started shooting little groups again. Too late for that aggregate, but hey.

That reminds me of the time I took my Marlin 60 with me squirrel hunting when I was camping out as part of our church retreat. Somewhere in the moving I must have banged the scope and moved it because after missing a squirrel badly (and making myself look like a rank amateur in the process ) I took notice that the scope had slid on the tip off mount. I guess I stuffed too much stuff in my old Raider before heading out to the woods. It's too easy to move a scope on a 60 anyway if you don't have the right mount and have it done right. I have since learned to put a dent under the lip of that dovetail right where the screws tighten down. It is great for keeping a scope in place. I haven't had a scope move on a 60 since I learned that trick. It takes a set of mounts that will grip that dent well too. But still it sure looked like I was the cause of that flyer (no squirrel for breakfast for me that morning). I couldn't believe I missed that shot. This was separate from the one I couldn't see through the scope on the next retreat because it got so close to the end of my rifle my scope wouldn't focus on it. I quit hunting with a scope after that but I do have a 60 set up for plinking with a scope on it. Come to think of it I did kill a squirrel with that rifle not too long ago.

But that's another example of learning what is what with a bad shot. I knew I hadn't done anything wrong on that shot so I tracked down what the problem was. It was too late of course but I figured it out. No one believed me when I told them that's what happened either. Funny how that works.

i know exactly how much powder is in my cases because i weigh every one to +/-.01g which is essentially one kernel of most extruded rifle powders. i've eliminated that variable, so i believe i can see changes in MV from other sources,

Is the powder always consistent enough to tell that much of a difference with such a small amount of powder? I'm not a reloader. I'm just curious about that. I've wondered about it before. I just would like to know if QC is good enough to tell to that degree what's going on?

 

[denton]

statements like this make no sense to me

An SD of .11 grain of powder translates to an MV SD of 11 FPS.
because it's not my experience at all.

Let me see if I can do a better job. In round numbers, at about the charges I was using, a grain more or less of powder produces about a 100 FPS change in MV, and the SD of the random error in my powder dispenser with the particular powder I was using is .11 grain. So .11 grains x 100 FPS/grain = 11 FPS. That's the additional muzzle velocity variation from switching from an ideal powder measure to one that I actually own.

The interesting question is, how much does that variation contribute when mixed with the other sources of variation?

We don't know exactly what the SD of my ammunition would be with perfect charges, but for an illustrative example it is OK to assume 25 FPS, as I did. You can assume any other value you like, and see what it does to the math. The long and short of it is that for most common rifles, and decent quality commercial ammunition, the variation in MV is not enough to affect accuracy enough to worry about. Benchresters who shoot 1/4" groups at 100 yards routinely load at the bench using a powder dump rather than a scale.

i know exactly how much powder is in my cases

Only The Almighty gets perfect information. The rest of us do not. .01 gram is .154 grains, which is not particularly excellent resolution.

If you're worried about such small amounts of powder, you ought to be shooting with a thermocouple attached to your barrel just ahead of the receiver. In 308/30-06 class cases, with most powders, 30 degrees F is roughly equivalent to a whole grain of powder. If you're not controlling barrel temperature to within about 3 degrees, there is no point in controlling powder to within .1 grain. (Data from Varget in a 7.62x54R.)

If you enjoy seeing how low you can get the SD of your MVs, have at it. If you're shooting a 1/2 MOA rifle at 1000 yards, it will make a difference. Otherwise, it's just an enjoyable pursuit with no measurable result. But since when do we need a reason to do what we do?

You might want to check out my QuikSigma channel on YouTube. There are some videos there that will help you. Been doing industrial applied stats very successfully for a long time, and what I've said is very orthodox according to the most reliable sources.

 

[taliv]

i'm weighing to +/- .01 grains, not grams and it is excellent resolution. to get better you would literally have to cut individual kernels of powder in half.

barrel temperature seems to play almost no role whatsoever in MV. i do control for the temp of the powder though, usually assuming it is at ambient unless i just pulled it out of a cooler or car or something. (of course, if you get a barrel hot and then leave a cartridge in the chamber for a while, it will warm the powder, but i don't do that)

most powders' temp sensitivity is in the range of .5 - 2 fps / *F so 30*F temp change would be 15-60 fps difference. so yeah, you have to track it in order to get first round hits on targets. no it may not matter much at 100 yards

 

[denton]

i'm weighing to +/- .01 grains

Thank you for the clarification. The standard abbreviation for gram is g, so I incorrectly assumed that is what you meant. Have you tested your scale to determine the amount of random error included in your measurements?

barrel temperature seems to play almost no role whatsoever in MV

You might find the following graph interesting. 200 PSI chamber pressure per degree F of barrel temperature.

"] [/URL]

 

[taliv]

i'm pretty skeptical about those numbers, as i have a pressure trace system and used to use it a lot and never really saw that. in any event, peak pressure does not correlate to MV all that well. (although it is what you want to watch to make sure your gun doesn't explode). look at all the graphs on this page http://www.shootingsoftware.com/pressure.htm and you will see there isn't really a trend toward increasing pressure with shot count, though you know the bbl temp is increasing.

www.thehighroad.org/showthread.php?p=9106860
see this thread for some measurements i took using a FLIR heat gun. it was actually the suppressor i was measuring, but as you can see from the attached videos, the barrel warms less than the suppressor i was measuring. you can see the chrono values (this wasn't low SD match ammo, just practice ammo and i think the 260rem ammo was mfg by southwest ammo). anyway, you can see the velocities don't show much of a trend if any. maybe you can pick it out better than i can, but i would have said despite a 100* change in temp over 10 rounds, there was no effect of MV.

judging by your graph above, they'd prob say 200* bbl temp would be 75k+ pmax?

 

[denton]

in any event, peak pressure does not correlate to MV all that well. (although it is what you want to watch to make sure your gun doesn't explode). look at all the graphs on this page

Actually, it correlates extremely well. How do I know? Take another look at the page you cite, and look at who wrote the articles they use. I knew the fellow who developed the PressureTrace, and actually helped him with a couple of minor contributions to its performance.

 

[taliv]

go look at the graphs on that page, if they supported a correlation, the peak for the last shot would be higher than the 1st, but that isn't the case on any of them, much less all of them .

go look at any reloading manual and you will see they show peak pressure and velocity with each load... there's no correlation between the two.
look at the measurements i provided with the FLIR and the chrono values.

if what you were saying is true, almost every string anyone ever recorded on a chronograph would start with low values and get higher. that isn't the case at all.

i am interested in how you would explain these things

 

[taliv]

apologies to the OP for the tangent. it is really hard to tell and takes a lot of effort to figure out what causes flyers.

 

[denton]

the peak for the last shot would be higher than the 1st, but that isn't the case on any of them

Not so, my friend. It is not at all required that the second always exceed the first. What is required is that there is an underlying trend that can be distinguished from random noise. Unless there is zero random noise in the system, your statement will often be untrue. There is no requirement that the data be monotonic.

Please have the patience to follow this:

For loads using the same powder and bullet weight, peak pressure and muzzle velocity are extremely highly correlated. This is because the bullet gets most of its energy near the peak of pressure. I have verified this correlation many times. Here is one data set to illustrate.

"] [/URL]

With R^2 = .99, there is no doubt that peak pressure and muzzle velocity are highly correlated under the conditions I have stated, which are also the conditions under which we would test for an effect from barrel temperature.

Yes, I understand that MV depends intimately on the total area under the pressure curve. But it is also true that using the same powder and bullet weight, MV and peak pressure are so well correlated that we can convert back and forth between the two quite freely. As peak pressure goes up, MV goes up.

Now refer back to the graph I previously posted, of peak pressure as a function of barrel temperature.

"] [/URL]

Peak pressure clearly goes up as barrel temperature increases. The data were taken using a Finnish Mosin, firing as fast as I could to deliberately raise barrel temperature. If memory serves correctly, the powder was Varget and the bullet was 150 grains.

By the exercise above, we can also state that muzzle velocity clearly increased with barrel temperature. To deny this is to deny the data.

almost every string anyone ever recorded on a chronograph would start with low values and get higher

It's always there, but sometimes the signal is strong enough to detect and sometimes it isn't.

Pressure barrels are massive. With SAAMI testing procedures, the mass of the barrel and the time allowed between shots for cooling combine to make the effect small enough to be masked by statistical noise in the system. You could still get it to pop up above the noise if you took substantially more data.

Burt, the fellow that developed the PressureTrace, was an avid benchrester. It's a very good bet that he let his barrel cool properly between shots. So I wouldn't expect any visible temperature trends in the data he posted on the PressureTrace site.

Lyman's 47, on the other hand, had a nice little set of raw pressure data. And sure enough, the trend was statistically detectable as the test progressed. Unfortunately, most of the books just give us 10 shot averages rather than the raw data, so that was nice to find.

In any event, if you want to assert that MV and peak pressure are not correlated at all, you'll need to provide an alternative explanation as to why peak pressure (and consequently MV) went up in my first graph, as barrel temperature increased.

 

[taliv]

look, you're saying barrel temp matters (not powder temp that everyone else uses.) because it drives peak pressure
and peak pressure matters because it drives MV (but that MV doesn't really matter)

I've showed you two barrel measurements with a FLIR gun that in just 10 rounds the barrel goes up over 100 degrees. It's very consistent.
and I showed you the chrono data to go along with it, where velocity didn't increase.

You said i needed to control to within 3 degrees because that was worth a whole grain of powder. and you're showing linear graphs correlating pressure and MV. but if barrel temp really drove peak pressure like you say (200 psi / degree) and peak pressure correlates with MV, then after a 10-20 round string MV should be crazy high, and the peak pressure would be so far above saami spec that guns would be disassembling themselves.

clearly, one or both of those relationships is not correct. it just can't be.

now, powder temp does make a difference and almost every ballistic calculator out there will take powder temp as an input variable. i have yet to see any ballistic calculator take barrel temp as an input.

 

[denton]

look, you're saying barrel temp matters (not powder temp that everyone else uses.) because it drives peak pressure
and peak pressure matters because it drives MV (but that MV doesn't really matter)

What I said was correct. Your twisted version of my statement is not.

Barrel temperature influences pressure and MV quite strongly. If not, my graph of pressure as a function of barrel temperature would be impossible.

Peak pressure does drive MV. Exactly contrary to your statement, the two are highly correlated. If not, my graph of MV vs. peak pressure would be impossible.

The amount of MV variation found in decent commercial ammunition is not sufficient to make much difference in the accuracy of the rifles most of us shoot. Striving to get MV standard deviation down into the single digits is a complete waste of time unless you are shooting at very long distances with exceptionally accurate rifles. Even then, the MV variation in decent commercial ammunition is not terribly important.

I've showed you two barrel measurements with a FLIR gun that in just 10 rounds the barrel goes up over 100 degrees. It's very consistent.
and I showed you the chrono data to go along with it, where velocity didn't increase.

You haven't shown me any such data, nor have you shown me a lack of correlation. And your claimed result is completely inconsistent with thermocouple measurements I have made. Look again at my first graph. 16 shots, fired very quickly, and only 40 degrees F increase in temperature.

You said i needed to control to within 3 degrees because that was worth a whole grain of powder.

Completely incorrect. Look again. I said 3 degrees F was worth .1 grain of powder in 308/30-06 size cases, and that if you're not controlling barrel temperature to within 3 degrees there isn't much sense in worrying about .1 grain changes in powder charge.

clearly, one or both of those relationships is not correct. it just can't be.

You're right there. Slipping a decimal will do that for you.

i have yet to see any ballistic calculator take barrel temp as an input.

Someday they will catch up.

I've done the experiments, and I have published the data that show what I have stated. No, I'm not going to publish it again just for you. You can believe or disbelieve as you choose.

Taliv, you're at the point that you are throwing around wild, unsubstantiated claims and twisting what I've told you. That's not much fun for me. We could have had a mutually beneficial discussion, but I think that is not possible now. So I'm ending this conversation.

 

[taliv]

You haven't shown me any such data, nor have you shown me a lack of correlation.

please see videos linked in post 41. mv/temps per shot are in post 3 of that thread

you're right. i missed when you said "a whole grain of powder" that you changed to 30*F instead of 3*. that certainly gets us closer together, but it is odd that all the experiments i've done and the data shown by pressure trace conflict with what you've done. oh well, thanks for the discussion.

 

[ChaoSS]

OP, while they are off on their tangent, let me offer up a couple suggestions.


If you are using decent ammo, with a good rifle and scope, let's just assume that the problem is you, and not the ammo/gun.

There's more ways to screw up a shot other than a bad trigger pull or moving the gun off target.

Taliv suggested parallax, and that was my first thought when I read your post. If you are shooting at 50 yards with a scope set to 100+ yards parallax, you could be seeing problems there. If your cheek weld is imperfect/inconsistent, then you could absolutely believe that you are dead on and then see a shot go off like that.

The other issue is cant. If your gun is not perfectly straight up and down (or at least held at exactly the same angle every time) then that will throw your shots as well. It doesn't take a lot of cant to throw your shot off, so once again, you'll be looking through your scope, convinced you are pulling off the perfect shot, and then it goes wide.


So yeah, see what happens when a more experienced shooter shoots your gun, see if they do better than you. Assuming they do, start working on making sure your hold is absolutely consistent from shot to shot.


Just one more thing to be thinking about while you are trying to hold the gun steady and pull off the perfect trigger pull.

 

[12many]

You all are way over my head. Reminds me of statistics, which I did not like, but that could have been because the teacher barely spoke English.

My next step is just getting a stable rest for the rifle. Thanks for the other tips. I learned a lot from this thread !!