Calculated velocity change caused by a single granule of Varget in a .308/175gr.

[jlow]

LOL! : A bit of a lost cause….People just won’t read the complete post Boyd…

 

[fguffey]

LOL! : A bit of a lost cause….People just won’t read the complete post Boyd…

I do not agree, many years ago a writer/shooter/reloader decided to purchase 500 cases from one manufacturer, the cases were said to be from the same lot. He started by culling cases that were different. He grouped/sorted the cases. Then he developed his loads, when finished he settled on 47 cases he considered perfect. After rejecting cases for various reasons he went back and fired them again, some of the cases he rejected were accurate if he indexed the case in the chamber.

Some of the cases he rejected had powder columns that were not centered, other cases had necks that would require turning.

F. Guffey

 

[BoydAllen]

fguffey,
My post had nothing to do with what you wrote. He is not having accuracy issues at 100 yards at all, but rather he is trying to reduce large ESs in anticipation of shooting at longer ranges where they will result in vertical dispersion. If your example involved the use of American brass, I can see how the problems that you mentioned would have been issues, but my experience with Lapua brass has led me to believe that he is unlikely to have those problems, that and the size of his 100 yard test groups.

 

[fguffey]

My post had nothing to do with what you wrote. He is not having accuracy issues at 100 yards at all

You are correct unless the shooter from 50+ years ago decided to load the 47 perfect cases for long range. The 500 cases he purchased were R-P.

F. Guffey

 

[savagedasher]

Internal case capacity must be the same before any worry about 1 kernel of powder
My Lapua Dasher brass I find more then a full grain of capacity in a 100 cases.
By doing the internal capacity I have lowered my ES to 8 or less . Using a charge Master.
I can use the same cases and change primers and the ES goes to 15 or better.
To find the right combination you must uses the same cases.
The cases I have sorted with internal capacity my ES is 8 or less. Change primers and they go to 15 +.
You will never get low ES if the internal capacity is different. And the wrong primer choice. Vertical does show at 100 YDS Larry

 

[Brians356]

My post had nothing to do with what you wrote. He is not having accuracy issues at 100 yards at all

You are correct unless the shooter from 50+ years ago decided to load the 47 perfect cases for long range. The 500 cases he purchased were R-P.

F. Guffey

Divergent trajectories. Is there a jug of corn likker being passed around here or something? Boyd will remember what he was saying when he wakes up tomorrow, anyway.

 

[Brians356]

Boyd,

Have you happened to look at the "1 grain velocity factor" published w/ the load data in "Modern Reloading Second Edition" by Richard Lee?

For 308 Win with 175-grain bullet, the 1-grain velocity factor for Varget is .9866. Purportedly, reducing the max load listed (45.0 gr @2690 fps) by 1 grain should lower the velocity to .9866 x 2690 = 2653.4 fps. The change per grain then is 36.6, and per tenth grain 3.66. Pretty close to your (or Hodgdon's) 3.7, huh?

 

[Webster]

If you had two extra kernels and the case had more volume would they cancel each other out?

 

[Dusty Stevens]

What if that primer weighed .01gr more than the rest?

 

[waldo1979]

0.02-0.03 grain per kernel of Varget sounds a about right to me. Velocity will very greatly depending on charge weight. Inside a solid accuracy node i would say 0.1gr variance would be something like 3-5fps (speculation) velocity change. I think primer quality would cause a bigger swing.

I use a magneto speed which is pretty good but a Oehler 35P is consider the de facto standard. I don't think they will hold 5fps tolerance, but I could be wrong.

I've heard that at 1000 yards every kernel matters.

 

[6BRinNZ]

Boyd - where did this end up for your friend? Did he get to the bottom of the 40 fps ES?

 

[amlevin]

What if that primer weighed .01gr more than the rest?

Are we supposed to weigh primers too?


I think I'm going to just move to some place that still has open garbage dumps. Shooting dump rats was more fun and we didn't need to become OCD to build ammo to shoot them. 8) 8)

 

[BoydAllen]

In one small test my friend lowered his ES to 12 by annealing, lowering his neck tension to .001 and using a nylon brush on the inside of his case necks, but still leaving most of the fouling in them. He has more work to do, but things look promising. His goal is excellent accuracy from 100 to 400 yards.

 

[Brians356]

In one small test my friend lowered his ES to 12 by annealing, lowering his neck tension to .001 and using a nylon brush on the inside of his case necks, but still leaving most of the fouling in them. He has more work to do, but things look promising. His goal is excellent accuracy from 100 to 400 yards.

There's such a state as "too clean" I believe. Which is why I have voiced bemusement towards folks who tumble brass after every firing, and debate which recipe produces the cleanest brass.

 

[BoydAllen]

Larry,
What primer is giving you the lowest ES? Of course this will not apply directly to my friend since he is using LR primers and your Dasher uses SR. If I remember correctly you are using a powder that is not typical for Dashers.

 

[savagedasher]

Larry,
What primer is giving you the lowest ES? Of course this will not apply directly to my friend since he is using LR primers and your Dasher uses SR. If I remember correctly you are using a powder that is not typical for Dashers.

Wolf & Tula the lowest next best is 205m CCI is last. in my guns.
Yes I use H4350 in my dashers.
Wolf in my 308 is the best also. Larry

 

[normmatzen]

Boyd,

I have had problems with you, but you are correct 99% of the time!

This time!!! You are right on the point, but NO ONE is hearing you!

NO ONE is reading your text!

I did, and I agree 100%!!

 

[Brians356]

What is harder to quantify is variability in how a bullet is released. We look at the difference in the neck diameter before and after seating, but in fact there are multiple factors at work, some of which we may not even be looking at. For example, years ago, one successful 1,000 yard shooter told me that as a final sizing step for his brass he uses an expander mandrel and die, and has a set of expander mandrels graduated in half thousandths. He said that he believed that it gave him a more consistent result. How many would have even thought to try that? Then there is the issue of the consistency of the coefficient of friction of the inside of case necks, which can be further complicated when annealing and/or cleaning with SS pins come into the picture. It goes on and on. I have not been on a ES quest in my reloading because I do not shoot at distances where that is a major factor. On the other hand, when I chronograph loads I have not seen numbers that cause me to be concerned. My friend has different ambitions.

“I didn’t work with chronographs because as long as a bullet went into the same hole as the previous one, it didn’t make any difference how fast it was traveling.” ... “The secret is to get the neck tension — the grip of the brass on the bullet — exactly the same on every case. You do this by firing the case and then feeling the bullet slide in the case neck as you seat it. Here, a micrometer won’t do you any good. Feel is the whole thing. If any case grips the bullet harder than the others, you take three turns over the sandpaper and fire it again, until you get exactly the same amount of seating pressure. Until the necks were tuned, I didn’t feel I was ready to start tuning the gun. You can change the powder charge slightly, and it won’t really make any difference, but if you change the bullet seating depth or the grip on the bullet, you’re going to see bad things happen fast.”

Virgil King (who seated using a Wilson seater by hand - no arbor press.)

 

[aj300mag]

There's such a state as "too clean" I believe. Which is why I have voiced bemusement towards folks who tumble brass after every firing, and debate which recipe produces the cleanest brass.

Not sure there's an issue with "too clean" brass. I know a couple of the top F-TR shooters who use virgin brass.

 

[Brians356]

There's such a state as "too clean" I believe. Which is why I have voiced bemusement towards folks who tumble brass after every firing, and debate which recipe produces the cleanest brass.

Not sure there's an issue with "too clean" brass. I know a couple of the top F-TR shooters who use virgin brass.

Wow. Load once, then discard. That must get expensive.

Truly virgin (new, unused) brass is seldom as clean as what some chaps are taking out of their tumblers. Virgin brass is a special case, and it's only "virgin" until it's sized and fired the first time. Thereafter it's reloaded brass - perfectly cleaned, or somewhat less so. As Boyd pointed out, it's possible leaving a little residue inside the neck may actually lower ES.