Weighed Charges at The Nationals

I loaded with a Chargemaster my first two years in this game (before the Chargemaster was in "vogue") and it served me well except for the fact that it was much too slow. At a big match where you have tons of time in between relays, it's a non-issue. But at local matches, I was either choosing to finish making ammo or to clean my rifle. I could not do both and still make it to the line in time. And then when you go to ranges that don't have an indoor loading area, the chargemaster was nothing but a headache. Wind, dust, and un-level table tops are death to the machine and death to your groups.

Bought me a Harrell's Premium thrower the next year and beat it against the Chargemaster and they both were accurate to .1 grain and I could load ten times faster with the Harrells which meant I got to clean my rifle and occasionally stroll over to the wailing wall too. Less fuss, less headache, and more enjoyable shooting with the Harrells. But I still load at the range with my Chargemaster.............for long range shooting! 95 grains of H1000 drops through the Harrells like Rosie O'fat falling through a storm drain cover.
 
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Lawdy,Lawdy,Lawdy,
Now I know why old women tune into soap operas on day time TV. I would hang around and mediate for you guy but I lit up a "muy malo" trash fire in the back yard just before dark and it shows no intention of laying down. It seems the combination of rotted railroad ties,old roof shingles,tar paper, defunct "Herculon" carpeting ,Walnut tree branches and cat box dumpings is what Satan uses to stoke the fires of Hell. I gotta go hook up the "big" hose.
Joel
 
This sort of reminds me of the story of the old ranch hand. He had just hired on at a new place and the foreman wanted to see if he had any work left in him, so he set him to fixing a long fence, figuring that it would take him a day or two. Later that day the old hand came back and told the foreman that he was finished. Impressed, the foreman told him to split and stack some firewood, figuring that that would keep him busy till quitting time, but as before, he finished the whole job with time to spare. Finally, not wishing to over work the old man, he gave him a pile of potatoes to peel, telling him to put the good ones in a pot and throw the rotten ones away. Around supper time, the foreman began to wonder what had happened to his new hand, and went to where he had left him peeling potatoes. There were a few potatoes in the pot, one or two in a pile, obviously bad ones, and the old hand was passed out cold. He shook the old hand by the shoulder, rousing him, and asked what the problem was, to which he replied that he didn't mind the peeling, but the decisions were exhausting.

Every time I see a bit of unpleasant back and forth on one of the boards, I am tempted to do some wholesale deleting. Usually I don't. But either way, it seems like the decision is exhausting.

Play nice boys, and remember that without being able to see facial expression or hear tone of voice, it is easy to upset someone when you don't intend to.
 
jackie schmidt said:
It might be as simple as percentages.

A .3 variation in in a powder column that weighs 70+ grns is a lot less, percentage wise, than a .3 variation in a powder column that weighs only 30 grns...........jackie
Click to expand...

I seem to recall an article (quite a few years ago) in which someone chronographed BBs fired out of a smooth bore barrel using only the primer to propel them. He was looking for the lowest standard deviation. It made me wonder if the powder charges of small capacity cases are more subject to the variations in primers than large capacity cases. Everyone has heard about ignition problems with the Rem UBR small primer cases under some circumstances, but I also remember a few people achieving very good results under other circumstances with the small primer. Anyway, it would be interesting to compare a somewhat larger case with the PPC/Beggs size cases and then some that are even larger.

There was also someone who experimented with an electronic ignition system to try to get moree consistent ignition, but I never did hear much about it and so I guess he must not have had much success with it. (I think he used a capacitive discharge system adapted from an automobile setup.)

It does make you wonder just how the 1K BR crowd achieves such low standard deviation loads on a regular basis. It may be all that sorting.
 
Jackie, your percentages make a lot of sense. I do believe however every 1K shooter weighs each powder charge quite precisely, so that .3 grain variation probably isn't there. Now that people are saying even weighed charges in a PPC still show relatively high velocity ES, I guess there is the question as to why can't we get the small case down to single digits?
 
One of the irregularities in charting SD and ES is caused by the fact that many shooters use screes settings on their chronographs at 2' or 4'. They need to go back and read some what Henry Childs (HBC) wrote a few years ago. These "shirt pocket" chrono's (Chrony, etc) that the screens are built in and even Ohlers that were shipped with a 2' pipe will not give accurate readings in SD and ES. Point here is don't get bent out of shape with data that is not accurately acquired.

For example, the test below Henry uses a spacing of 48', not 48".
http://www.benchrest.com/forums/showthread.php?t=63733&highlight=screen
 
jackie schmidt said:
It might be as simple as percentages.

A .3 variation in a powder column that weighs 70+ grns is a lot less, percentage wise, than a .3 variation in a powder column that weighs only 30 grns...........jackie
Click to expand...



Jackie, I believe you are right on with this theory. :)

Gene Beggs
 
JerrySharrett said:
One of the irregularities in charting SD and ES is caused by the fact that many shooters use screes settings on their chronographs at 2' or 4'. They need to go back and read some what Henry Childs (HBC) wrote a few years ago. These "shirt pocket" chrono's (Chrony, etc) that the screens are built in and even Ohlers that were shipped with a 2' pipe will not give accurate readings in SD and ES. Point here is don't get bent out of shape with data that is not accurately acquired.

For example, the test below Henry uses a spacing of 48', not 48".
http://www.benchrest.com/forums/showthread.php?t=63733&highlight=screen
Click to expand...


Jerry,

I think that even a cheap chrony shows relative velocities quite accurately. It may read 'high' on a bright day and 'low' on a dark day and the readings may change as the angle of light changes...... and they may well be poorly calibrated, but if you get a strings like

3142
3143
3142
3140
3147

day after day for one load, and ES velocities are all over the map with other loads.....then it doesn't really matter that the ACTUAL velocity may well be 3100 or 3200, that's a fine string of numbers.

For accurate velocity readings day to day (for tuning) I've found that the cheap chronographs want to be in a controlled environment under artificial light. Under artificial light I'm convinced that I can get maningful ES dats from a chrony.

IMO for Bench Rest ES is all that matters, SD is for theoreticists and keyboard shooters. AND for the manly types which stand up on their hind feet and SHOOT.... these bad boys thrive on percentages, they live and die by averages and means.

But for me I want under 10fps.

al
 
alinwa said:
IMO for Bench Rest ES is all that matters,
Click to expand...

Never seen wood handed out for lowest ES at a BR tournament. Normally group size or score are all that matter.

SD is for theoreticists and keyboard shooters.
Click to expand...

And for those who can do math beyond subtraction.

AND for the manly types which stand up on their hind feet and SHOOT.... these bad boys thrive on percentages, they live and die by averages and means.
Click to expand...

Those of us who sit on our brains to shoot live and die by averages, too. We call them "aggregates."

But for me I want under 10fps. al
Click to expand...

And if you understood SD you could figure out what proportion of 5-shot strings will have ES > 10fps, without having to shoot the more than the 10 or 20 shots needed for a decent estimate of SD. ;)

Toby Bradshaw
baywingdb@comcast.net
 
tobybradshaw said:
Never seen wood handed out for lowest ES at a BR tournament. Normally group size or score are all that matter.



And for those who can do math beyond subtraction.



Those of us who sit on our brains to shoot live and die by averages, too. We call them "aggregates."



And if you understood SD you could figure out what proportion of 5-shot strings will have ES > 10fps, without having to shoot the more than the 10 or 20 shots needed for a decent estimate of SD. ;)

Toby Bradshaw
baywingdb@comcast.net
Click to expand...

Opinions vary, ;) I'm primarily a group shooter.

I understand SD, it's just not something I consider to be useful. There's no "math" to understand here, it's just not useful IMO. Especially not when applying it to velocity. SD is useful for those rifles or situations where a persons ability may well trump the accuracy of the rifle system. SD is for people who have to make choices based on something other than intrinsic accuracy. I don't have to make that choice. Folks who concentrate on score can benefit from a rifle which may be less accurate but more forgiving in the wind. BR guys have made this choice at times, for instance if one is choosing between a 6DAsher on one hand and a .338 on the other and it's howling a switchy gale it may be beneficial to go for the larger but less accurate bullet. But this isn't really relevant to applying Standard Deviation analysis to velocity.

When analyzing whether or not to shoot a VLD or a FB bullet in the wind SD is a useful tool, but not for applying to velocity deviation at long range.

IMO

I guess if one was cursed with a rifle which gave you two options, either shoot big and round or tight but with 20% droppers then you 'could' analyze your chances using SD but I don't consider that to be useful. In BR accuracy pretty much trumps all else, especially when shooting for group. 4 or 9 in a tight knot with a big ol' dropped shot will show really good on your SD analysis but will lose the match every time.

To a group shooter EVERY BULLET HOLE counts.

bummer

:)


al
 
tobybradshaw said:
And if you understood SD you could figure out what proportion of 5-shot strings will have ES > 10fps, without having to shoot the more than the 10 or 20 shots needed for a decent estimate of SD. ;)

Toby Bradshaw
baywingdb@comcast.net
Click to expand...


BTW, I saved this separately.

This statement makes my point.

You consider this relevant, I don't.

I don't do "decent estimates."

nor "proportions"

EVERY shot

bummer

al
 
alinwa said:
Jerry,

I think that even a cheap chrony shows relative velocities quite accurately. It may read 'high' on a bright day and 'low' on a dark day and the readings may change as the angle of light changes...... and they may well be poorly calibrated, but if you get a strings like

3142
3143
3142
3140
3147

day after day for one load, and ES velocities are all over the map with other loads.....then it doesn't really matter that the ACTUAL velocity may well be 3100 or 3200, that's a fine string of numbers.

For accurate velocity readings day to day (for tuning) I've found that the cheap chronographs want to be in a controlled environment under artificial light. Under artificial light I'm convinced that I can get maningful ES dats from a chrony.


al
Click to expand...


Al, did it ever occur to you that if your 3142, 3143, etc numbers are in error in relation to the true velocities of those shots that your summary data, Mean Velocity, Standard Deviation, and Extreme Spread will be junk?

In most artificial light sources a sky screen based chronograph will give really wild results just because of the 60 cycle flicker of the light source.

And, we have not even discussed sample size yet and how that relates to accuracy.
 
I think that the only arguments against increased precision in measurement and the largest possible sample size, relate to cost, time availability, practicality, and the relative importance of what is being measured.

We operate within limits that are very real. Available time, budgets, barrel life, shooting conditions, and the fact that if one only concentrates on reducing velocity variations, another factor may prevent us from seeing perfection at the target, all come into play. Because of this, we make what may be statistically unsupportable inferences from samples that are admittedly much smaller than the ideal. We do the best we can with what we have, based on our judgment about what is most important, and what is likely to get lost in the noise.

What we saw, in the results from the latest NBRSA Nationals, is evidence that equipment and its operators have gotten so good, when conditions are ideal, that the "noise" is reduced to a level that an adjustment of priorities may be in order. Things that once were insignificant, have become real factors to be considered more seriously in this relatively new era of aggs in the mid ones. Under perfect conditions, the truth about what matters may have changed. In recognition of this, some of the best shooters are now weighing charges. I doubt that they would be doing so if they could not see a difference at the target. So what is it that more uniform charge weight gives us that improves average accuracy? A logical inference would be that it produces more uniform velocities. If this is actually the case, then it only makes good sense to explore other factors that may have the same effect. Bullet pull, primers, flash hole consistency and shape, uniformity of case capacity, and bullet weight all come to mind. Maybe we would benefit from setting up our chronographs every time we practice, to increase the available data. Ugh! More crap to haul, set up and repack. Just what I wanted. On the other hand, maybe, at my skill level, with my equipment, and the conditions that are normal to where I shoot, the difference would still be lost in the noise. There is only one way to find out. You mean I have to change what I have been doing in order to find out? How rude.;)
 
alinwa said:
EVERY shot
al
Click to expand...

If you measure extreme spread you are not using the data from every shot. You are throwing away the data in the middle. So, you are not counting every shot. SD does use all the information.

Just for my edification, how many 5-shot strings does it take you to come up with your "exact" value of ES for a particular load?

And, if you had the following velocity data from 10 shots per load (with all other variables the same), how would you calculate ES (and any other stats you consider useful)? Which load would you choose for competitive short-range BR, and why?

Load 1 Load 2 Load 3 Load 4
1000 3350 3354 3350
1000 3350 3354 3360
1000 3350 3354 3350
1000 3350 3354 3360
1000 3350 3354 3350
1000 3360 3354 3360
1000 3360 3354 3350
1000 3360 3354 3360
1000 3360 3354 3350
1000 3360 3364 3360

Toby Bradshaw
baywingdb@comcast.net
 
Boyd Allen said:
We do the best we can with what we have, based on our judgment about what is most important, and what is likely to get lost in the noise.
Click to expand...

That is my impression of what the winning shooters I know are doing. More time practicing and watching flags, less time crunching chronograph numbers or fiddling endlessly with loads.

It would be interesting to know how many aggs have been lost by vertical rather than horizontal dispersion. Personally, I never felt vertically challenged, but I have shot way too many "slots" or 4-and-1s with the 1 hanging out left or right. :)

Toby Bradshaw
baywingdb@comcast.net
 
Butch Lambert said:
So you think vertical is out of tune and horizontal is caused by the wind?
Butch
Click to expand...

For the most part, yes. Think about it. The barrel vibration is mostly up and down due to the effect of gravity causing barrel droop.

Most of the horizontal is caused by variations in velocity within the air mass you are shooting though. I know from using tuners that the prime effort is getting out the vertical.

Notice I said most, not all.

Look at it this way, tune and get the vertical out, then improve your flag reading skills to get the horizontal out and BINGO, you are a winner.
 
Butch Lambert said:
So you think vertical is out of tune and horizontal is caused by the wind?
Butch
Click to expand...

To a first approximation, yes.

That's not to say that wind (including its interaction with terrain) can't produce vertical dispersion. Obviously it can/does. When tuning I try to test in a condition that lets me see the effect of the load on vertical, and deal with the vertical effect of the wind/terrain later by checking on the sighter in different conditions. I always assumed that's pretty much how everybody tunes, but maybe I'm about to learn something. :)

I've never noticed that powder charge does anything to help much with horizontal dispersion, though, at least at the 100-300yd I shoot.

How about you?

Toby Bradshaw
baywingdb@comcast.net
 
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