Weighed Charges at The Nationals

Regardless

We can all beat around the bush when this subject comes up, but as I said in my originol post, you cannot help but notice the number of top ranked shooters who are now weighing each charge to the nearest tenth of a grn.

Yes, it is an added hassle. Yes, you have to be very meticulous so that you do not induce error into the weighing proccess.

But, in the long run, it is something that is worth while doing.

While I did not shoot that well at Saint Louis, I darned sure took notice of many of the innovations that have cropped up over the past couple of years. One, it is very difficult to compete without an ejector Rifle. Not impossible, but difficult. Two, just because a Rifle will shoot in the wind is no guarantee that it will be competitive in a near dead still condition, esspecially when the standard is in the .150 agg range. Third, the old wives tale of "if it is in the load window, a few tenths one way or another doesn't matter" From the results that came out of Saint Louis, I supect this is simply not true......jackie
 
Jackie,

If you have a truely good scale, you will see why they are doing it. It is about repeatability and predictability of your tune. It is ridiculously easy to get a rifle tuned with very good weighed charges. It won't fix a bad barrel or bullets as you know, but if everything else is right you can dial in your tune as was seen at the nats. That is not an opinion, I know it works. Different powders will also give different results. I'll bet that most of the N133 is being weighed.
 
Last edited by a moderator:
Does anyone know how many if any of the first 20 teen aggs had tuners on their barrels?

Donald
 
caroby said:
Yes.....................................

Gene, would you say the Russian Wolf SRM primers are giving "better" performance in the tunnel..? I'm starting to really like them. Just this last weekend I was shooting the Wolf SRM and 205 over my Chrony........... I did see more consistently lower ES's from the Wolf's.... Not real small, but just more consistent mid teen ES's.

Groups were about the same...Darn let-up's!:rolleyes:............ No tunnels where I live....;):(

cale
Click to expand...


Cale, the Wolf SRM primer is giving me the lowest extreme spreads thus far. I must thank Stu Harvey for introducing me to them.

Gene Beggs
 
alinwa said:
I don't know from SD (seems like a goober fudge-number to me)al
Click to expand...

The reason that SD is preferable to ES as a descriptor is the ES increases with sample size, whereas SD does not.

Here's an (approximate) example. Start with a pile of pennies. Toss each penny ten times and record the proportion of heads and tails. The most common outcome will be 5 heads and 5 tails (the mean, median, mode, or average of the outcomes). As you toss more and more pennies, you are more and more likely to get extreme values (for instance, roughly 1 out of a 1000 times you will get all heads, or all tails). So, reporting "extreme spread" is not very informative unless the sample size (number of coins tested) is also given. This is why ES alone (without number of shots) is essentially worthless as a descriptor.

On the other hand, the SD of the coin toss experiment is simply calculated (from the binomial distribution) as 1.6. If you know something about the SD, you realize that roughly 2/3 of all coins tested will fall in the range of +/- 1SD from the mean, 95% will fall within 2SD of the mean, and >99% will fall within 3SD of the mean. So, with a mean of 5 heads (out of 10 tosses), 95% of the time we will come up with between 2 and 8 heads out of 10 tosses (that is, 5 heads plus or minus 2*1.6).

It is true that the estimate of SD improves with increasing sample size (number of shots, in the case of a rifle), but with more shots it converges on the same number. ES, conversely, never converges, it just keeps increasing as the number of shots increases.

Toby Bradshaw
baywingdb@comcast.net
 
Last edited by a moderator:
Gene Beggs said:
We often hear claims of single digit extreme spreads but I have never been able to achieve that with either the 6PPC or my 6mm Beggs cartridge. About the best I can do is around 18 to 25 fps. I shoot the 6mm Beggs at an average 3360 fps with 66 to 68 grain bullets, the same as the 6PPC; accuracy is excellent with both cartridges even when ES shows as much as 40 fps. Can someone please explain this? :eek:

Gene Beggs
Click to expand...

Here's a partial explanation. ES is more critical at long range than at short range. If you run your parameters through a ballistics program you can see this. Assume a mean of 3360fps with a bullet having a G1 BC of 0.270. If your 5-shot group has an ES of 20fps (3350-3370fps), the difference in drop between the slowest and fastest bullet at the 100, 300, and 600yd is:

Inches: 0.02, 0.23, 1.40
MOA: 0.02, 0.08, 0.23

So, an ES that produces hardly any vertical at 100yd can produce 10 times as much vertical (in MOA) at 600yd.

Your tunnel isn't 600yd long, is it? :)

To me, the lack of testing at 200 and 300yd in the Houston tunnel (where up to 300yd apparently was possible) was a bit of a disappointment. Much could have been learned that would benefit the medium-range game, I suspect.

Toby Bradshaw
baywingdb@comcast.net
 
Wayne Shaw said:
The long range guys strive for the lowest ES they can get. They weigh their primers and segregate them.
Click to expand...



Wayne, I have never tried weighing primers in addition to weighing charges. I'll have to try it and see if it lowers extreme spreads with my 6mm Beggs cartridge. I hope it doesn't because I wouldn't welcome the additional work. :eek:

The 1000 yard shooters strive for and consistently achieve single digit extreme spreads with their larger capacity cases, but I defy anyone to do it with a 6PPC.

Gene Beggs
 
Gene Beggs said:
Al, I use an O'Haus lab scale that splits a tenth into ten parts.

Gene Beggs
Click to expand...

Well, it seems like that would do it, a kernel of H4350 weighs just over .02gr and 133 is half that.

I know that for myself I must load in a temp controlled room, re-zero the scale constantly and after I'm done go back and recheck about 20-30% of the charges through the block (75-100rds) to see did the 'lectronics wander off into no man's land.

It's a complete pita but I do weigh to within +- 1 kernel of powder and if I don't my ES goes away.

I've also found primers to have an effect on ES BUT...... for me it's about finding the primer that best ignites the powder I've chosen and setting them to correct crush depth when seating. I haven't weighed primers. Finding low ES was/is hard.

al
 
Gene Beggs said:
The 1000 yard shooters strive for and consistently achieve single digit extreme spreads with their larger capacity cases, but I defy anyone to do it with a 6PPC.

Gene Beggs
Click to expand...

This might be a key point Gene, I've never actually done it with a PPC and 133.

I'll try it soon.

al
 
Pete Wass said:
Gene, have you ever tried 30 Caliber rifles? I am beginning to suspect that there is a great divergence between what smaller bores do and larger bores. After all, all of us can't be wrong, can we? Having said that, I have noted over the years that we often talk past each other on some of this stuff. We know what we see and think the other people are somehow wrong. Perhaps we are not so wrong but simply seeing a different set of results from different equipment.
Click to expand...


Pete, I have very little personal experience with 30 caliber rifles, but several shooters have tested them in my tunnel. I was impressed with their accuracy. Shelley Davidson's 'Tinker Toy' comes to mind. I'm sure you are right about bore sizes; the smaller bore, high intensity cartridges seem to be more sensitive to tune.

Gene Beggs
 
I have wondered

if the density of the powder varies in some throws thus causing variations in weight. I tried the technique of tappint on the top and that seems to aid in consistency but does not totally eliminate it. Apparently if folks find weighed charges " rediculously easy to tune" there must be some relevence to x weight of powder equaling Y amount of thrust, just like any fuel, eh.
 
Last edited:
jackie schmidt said:
, I darned sure took notice of many of the innovations that have cropped up over the past couple of years. One, it is very difficult to compete without an ejector Rifle. Not impossible, but difficult. Two, just because a Rifle will shoot in the wind is no guarantee that it will be competitive in a near dead still condition, esspecially when the standard is in the .150 agg range. ..jackie
Click to expand...
But, did you notice what Tony brought out in HV? The old DGA. But, then again that is Tony and we is us!!!
 
Bommy Wommy ?

See what happens when I leave you guys alone for a couple of hours !

Thanks to Toby for explaining the Standard Deviation thing as is related to coin tossing, my brain is still smoking ! Perhaps He can explain this phenomonon ?
For about a 10 year period( before Benchrest) my hunting buddy and I would cruise the Upstate NY chuck fields in search of marmota monax( that's a fancy name for a ground hog),once he was spotted and it was deemed that he was at a sporting distance and was in a shootable position we would flip a coin and the non flipping guy would "call it in the air" to decide who was up first(for the remainder of the day we would alternate back and forth on subsequent chucks).Well, to the maddening frustration of my companion,through hundreds of flipped coins,I never lost a toss ! Is that a zero Standard Deviation ?
Joel
 
Nader said:
Bommy Wommy ?

See what happens when I leave you guys alone for a couple of hours !

Thanks to Toby for explaining the Standard Deviation thing as is related to coin tossing, my brain is still smoking ! Perhaps He can explain this phenomonon ?
For about a 10 year period( before Benchrest) my hunting buddy and I would cruise the Upstate NY chuck fields in search of marmota monax( that's a fancy name for a ground hog),once he was spotted and it was deemed that he was at a sporting distance and was in a shootable position we would flip a coin and the non flipping guy would "call it in the air" to decide who was up first(for the remainder of the day we would alternate back and forth on subsequent chucks).Well, to the maddening frustration of my companion,through hundreds of flipped coins,I never lost a toss ! Is that a zero Standard Deviation ?
Joel
Click to expand...
Bommy Wammy is what my wife calls our new, and very best, gun salesman. Since Mock is of the same political party, I call him that.

As to Standard Deviation, that would have been the number of times out of the total number of times your buddy left you standing in the road when he found out about that 2-headed coin you used on him.

BTW, next time use the JNHCF commemorative quarter in your shooting box!!
 
Nader said:
Well, to the maddening frustration of my companion,through hundreds of flipped coins,I never lost a toss ! Is that a zero Standard Deviation ?
Joel
Click to expand...

Yes. With luck like that you should have been buying lottery tickets instead of persecuting helpless rodents. :)

Toby Bradshaw
baywingdb@comcast.net
 
Gene Beggs said:
Wayne, I have never tried weighing primers in addition to weighing charges. I'll have to try it and see if it lowers extreme spreads with my 6mm Beggs cartridge. I hope it doesn't because I wouldn't welcome the additional work. :eek:

The 1000 yard shooters strive for and consistently achieve single digit extreme spreads with their larger capacity cases, but I defy anyone to do it with a 6PPC.

Gene Beggs
Click to expand...

Gene, I don't disagree, but the question is why? The 1K guys use much bigger cases, thus more powder, more everything. I know BR shooters are claimed to be anal, but the successful 1K guys are that and more. They weight everything, measure everything, even clean the cases after each firing (ultrasonic bath of sorts, inside and out) so the carbon buildup inside is eliminated. Every variable is addressed, sorted and eliminated if possible. At the very least, variables are segregated. They do achieve real low ES, and they have to. The velocity variation at that distance is quite important, not so much at 100-300 yards.

Since the PPC (or Beggs) is claimed as the most accurate cartridge ever, why can't the ES be lowered to a consistent low number? If the big cases can be made to shoot low ES, why not the PPC?

I don't have any real answers, just asking the questions.
 
Wayne

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
 
You must log in or register to reply here.
Back
Top