How does measuring powder accurately translate to distance accuracy?

[bored184]

I am getting back into reloading after being out for bit with the goal to start getting into long distance precision shooting. I am fortunate enough to have a Parker tuned Lyman M5, Ohaus lab scale that can do .02 grains, RCBS M500 mechanical scale and a RCBS uniflow with the metered attachment. Perusing the web I now see digital scales that can measure to the 1/1000th of a grain. While digging everything out and reading till I only confused myself more I had a thought. At what distance does measuring to the nearest 1/1000th grain come in compared to 1/10th of a grain? In other words if you shoot say 100 - 300 yards will see any differences measuring out the the 1/1000th grain? I do see when shooting out to 1000 yards where the extra decimals places would be handy.

 

[Bob3700]

I am getting back into reloading after being out for bit with the goal to start getting into long distance precision shooting. I am fortunate enough to have a Parker tuned Lyman M5, Ohaus lab scale that can do .02 grains, RCBS M500 mechanical scale and a RCBS uniflow with the metered attachment. Perusing the web I now see digital scales that can measure to the 1/1000th of a grain. While digging everything out and reading till I only confused myself more I had a thought. At what distance does measuring to the nearest 1/1000th grain come in compared to 1/10th of a grain? In other words if you shoot say 100 - 300 yards will see any differences measuring out the the 1/1000th grain? I do see when shooting out to 1000 yards where the extra decimals places would be handy.

I too have that same question. My question: at what point is the accuracy of measuring powder meaningless. One of my shooting buddies has a Prometheus automatic powder measure. Big dollars. I use a lab grade electronic scale that measures to 1/1000 gr. I don't know just how accurate the Prometheus is but I can tell you that we both see the same level of accuracy out to 1000 yds. I measure my powder to +/- .01 gr.

 

[rockable]

Let' say your load is 40 grains of powder. .1 grain/40 grains= .0025 or 1/4%. Don' you think that' accurate enough? That is about 1 kernel of Varget. I know you'e not going to split kernels of powder.....are you?

 

[Bart B.]

1/10th grain is enough through 2,345 yards or more..

The small spread in each of several chemical components in each powder particle masks any finer units.

The spread across several primer's fire output also masks more precise charge weights.

 

[JohnKielly]

I know you'e not going to split kernels of powder.....are you?

But surely you could trim them all to the same length?

 

[Ron Blain]

My local range is Kebly's Rifle Range home of the annual Super Shoot in the bench rest 100 & 200 yard community. While I am not a bench rest type I very much enjoy the range. These guys load on the range and when signed up for the Super Shoot each shooter gets a bench in one of the large buildings. I have never seen a shooter using a scale as I wandered the buildings. The guys out there shooting the tiny groups out to the 200 yard line are all using volume metered powder dispensers like the higher end Harrell's Powder Dispensers. Most of these guys can't even tell you the weight of their charge but they can tell you exactly how their volume dispensers are setup. I have heard the long range guys shooting the F class matches are more concerned with their charge weight but have not chatted with many. I will say with weighing charges I think we hit a point of diminishing returns where other factors will carry more weight than the uncertainty of our powder charges. That being just my take on how much uncertainty we can live with in a powder charge.

Ron

 

[JimSC]

develop to the kernel so you can load with a dipper. My opinion is a good load will deliver the same results over several tenths of a grain. The problem is when you are using qn scale that has a .1 resolution to develop then your test cases can be .3 grains different when weighed. However if you weigh to the kernel and find a flat spot .3 or .4 gns wide with a flat velocity curve you can load to the middle of that spot and still be .1 off in either direction with loads will shoot pretty close to the same velocity. Mathematically ES's don't have that much of a effect on POI until after 500 or so however I do wonder if a high SD could cause flyers. Maybe some barrel harmonics guru can answer that

 

[jr600yd]

Years ago at Camp Perry I was told every .01 of charge varience moved the bullet impact 1” at 1,000 yds. Don’t know if it’s true considering the way I shoot.

 

[newbieshooter]

Let' say your load is 40 grains of powder. .1 grain/40 grains= .0025 or 1/4%. Don' you think that' accurate enough? That is about 1 kernel of Varget. I know you'e not going to split kernels of powder.....are you?

One kernel of Varget on my scale, weighs on average .023 grains.

 

[retired]

o

My local range is Kebly's Rifle Range home of the annual Super Shoot in the bench rest 100 & 200 yard community. While I am not a bench rest type I very much enjoy the range. These guys load on the range and when signed up for the Super Shoot each shooter gets a bench in one of the large buildings. I have never seen a shooter using a scale as I wandered the buildings. The guys out there shooting the tiny groups out to the 200 yard line are all using volume metered powder dispensers like the higher end Harrell's Powder Dispensers. Most of these guys can't even tell you the weight of their charge but they can tell you exactly how their volume dispensers are setup. I have heard the long range guys shooting the F class matches are more concerned with their charge weight but have not chatted with many. I will say with weighing charges I think we hit a point of diminishing returns where other factors will carry more weight than the uncertainty of our powder charges. That being just my take on how much uncertainty we can live with in a powder charge.

Ron

it is NOT long range, so that is an apples to oranges comparison.

 

[retired]

what scale it that m that is accurate to 0.0005..about where you would have to be to claim accuracy to 0.023 ?

One kernel of Varget on my scale, weighs on average .023 grains.

 

[retired]

in long range ACCURATE shooting, consistency in all the small things adds up.
so we do things that are more consistent than that required for short range shooting.

because it shows on the target

 

[Ron Blain]

o

it is NOT long range, so that is an apples to oranges comparison.

I agree but the original post and the thread starter stated:

In other words if you shoot say 100 - 300 yards will see any differences measuring out the the 1/1000th grain? I do see when shooting out to 1000 yards where the extra decimals places would be handy.

My post was based on 200 to 300 yards which is what the original poster mentioned. What resolution is needed for loading when shooting 200 or 300 yards. I assumed the thread was not about F class where we are at the 1,000 yard line.

Ron

 

[hogpatrol]

I sort powder sticks by length and then use micro drills to maintain the same burn rate for each one. This process was described on the main site in a daily bulletin a few years back.

http://bulletin.accurateshooter.com/?s=drilling+powder+kernels&submit=Search

 

[ClassCat]

I sort powder sticks by length and then use micro drills to maintain the same burn rate for each one. This process was described on the main site in a daily bulletin a few years back.

http://bulletin.accurateshooter.com/?s=drilling+powder+kernels&submit=Search

T-32 , 45710, 18167, 6196,12020.18166, and many others are pre drilled. LMAO

Actually the extrusion machine has a pin center that gives the appearance of drilling. it is actually part of the manufacturing.

 

[Bart B.]

Years ago at Camp Perry I was told every .01 of charge varience moved the bullet impact 1” at 1,000 yds. Don’t know if it’s true considering the way I shoot.

Sierra's load data for powders used in the 308 Win with their bullets cause about 6 to 7 fps change in muzzle velocity for each 1/10th grain change in charge weight. So a 1/100th grain change should change velocity about .65 fps average.

A decades old rule of finger for the 308 Win at 1000 yards has been 40 inch vertical group spread for a 100 fps spread in bullet muzzle velocity. That's .40" vertical spread for a 1 fps spread in velocity, a .25" vertical spread in muzzle velocity for a 1/100th grain spread in muzzle velocity.

Therefore, draw your own conclusions as few, if any, rifles and their ammo keep all fired group's vertical shot spread under 4 inches at 1000 for the lives of their barrels.

 

[6ShotsOr5?]

T-32 , 45710, 18167, 6196,12020.18166, and many others are pre drilled. LMAO

Actually the extrusion machine has a pin center that gives the appearance of drilling. it is actually part of the manufacturing.

Since these are hollow I use them to top off my charges that have too low of a fill ratio. Tastes terrible, more filling.

 

[ClassCat]

Since these are hollow I use them to top off my charges that have too low of a fill ratio. Tastes terrible, more filling.

Like a shot of Jack in a Blue Moon ?

 

[powderbrake]

what scale it that m that is accurate to 0.0005..about where you would have to be to claim accuracy to 0.023 ?

I agree one piece of varget is around .02 grains. That is measured on an A&D FX100i which has a resolution of.o2 grains. Typically scales are limited in the number of digits of display to be within their accuracy limits. the resolution limit on my scale is .o2 grains or .oo1 grams.

To refer to the original question, the short range 100 & 200 yard guys are weighing to somewhere between .1 to .02 grains by weight, and the longer range guys lean towards the lower end of that range.

It is hard to better than +or - .2 grains on a powder dispenser over a large amount of throws. Some guys are better than others. I can't do it, I have lyman, NielJones, RCBS, and Harrels BR measures, and have weighted 25 to 50 throws on all those measures, and I get + - .2 grain in the list of weights. I consider that too wide for accurate, competitive shooting , so I use an A&D FX100i with an Adams thrower and trickler to weigh my charges to within .02 grains. That way my errors on the target are due to other matters including not enough talent by the shooter.

 

[CharlieNC]

If you developed your load utilizing a ladder or similar technique based on identifying a node via positive compensation, weight differences will not matter as much as if the load was chosen based on group size.