How critical is measuring powder to .01 grains

[yobuck]

I used to do that plus: weight sorting bullets, sorting bullets by bearing surface, case sorting by weight, case sorting by volume, using a concencriticy gauge on every loaded cartridge and fixing run out, and finally....... bought a fx120 to ensure I was getting .01-.02 grain weights.

I am better now, doctor said my brain function will be back to full normal once I stop worrying everything and focus on only what matters at my level.

Well fortunately i never allowed myself to fall into that pit.
And ive always looked upon those who do with a bit of suspicion. lol
But then im simply a hunter, with that level of mentality.
If at first you dont suceed, try again.
Which also means keep the lead flying till its over.

 

[BrentM]

Well fortunately i never allowed myself to fall into that pit.
And ive always looked upon those who do with a bit of suspicion. lol
But then im simply a hunter, with that level of mentality.
If at first you dont suceed, try again.
Which also means keep the lead flying till its over.

Yeah I was getting into the weeds because of the person mentoring me. I am happy to have moved on.

 

[Rockbottom]

In my early reloading days, I didn't have calibrating weights. I made "standard" weights out of a piece of brass rod trimmed to match the weight of my favorite powder loads. There was a different rod for each of the variations of bullet weight, type and powder types. I didn't know the weight of any load to +/- 0.??gn, but I knew I could match them to much better than 0.1gn on my Redding #3 scale. It was fun, but with my rifles, it didn't matter.

 

[yobuck]

I always use a match grade bullet to check my scale and figure thats close enough.

 

[Rockbottom]

I always use a match grade bullet to check my scale and figure thats close enough.

Agreed. I made my weights from something that couldn't accidentaly be sent downrange. And "match grade" bullets weren't common in 1959, if they existed at all..

 

[lowdowndirtybugger]

This was shot with a new load in a new gun 100 rounds down the tube is all
This is 1500 yards shot on the bottom hit first. Came up .2. next was the one just off the edge. Shot was called low right came up .1. next 6 were all in a line. It was a gusty day 2 shots landed off the left edge the next 4 walked right as the wind died. As you can see the 4 in a row we're all in line with elevation. With 2 shots landing next to each other.
This is why .01 grains matter along with brass prep.
If there was .1 grain deviation it would show in vertical stringing.
The reason I started caring about exact loads is the years previous with high and low misses due to SD

 

[Axl]

I'm amazed that no precision shooters haven't jumped on this thread and cried "Bulls--t". But the reality is that if you are looking at charge weight variation there are tools like Quickload and Gordon's Reloading Tool that can provide realisticc estimates of what a weight variation can yield in terms of velocity variation. In a 308 cartridge with 43 gr of IMR 4064, a 168 SMK and Lapua brass at 56gr of water capacity, a 0.1gr variation in powder yields a velocity difference of ~6 fps. This is pretty much the same for any cartridge in the 40-50gr charge weight range. Similarly, a 2.6 grain difference in brass weight for that cartridge, if all the difference is in actual case capacity is about 0.3 gr of H2O capacity and results in about the same velocity variation. Generally in higher capacity cartridges the results would vary less for the same variations in weight.

A lot is made of scales like the AnD Fx-120i that have .02 gr resolution. This scale actually has an accuracy of ~.05 grains when compared on an equal basis with those that claim an accuracy of .1gr.

These are theoretical values of course but important because they are based on actual theory and testing. As for seeing and measuring these differences that is a much more complicated exercise. Evan a Labradar will have trouble measuring velocity differences of 3 fps accurately and there are many other variables like powder orientation, neck tension, primer variations, bullet weight variations, etc that introduce noise into the results.

I am amazed this thread sat dormant for a decade with 18 posts- and now has over 100 in a couple days.

 

[yobuck]

This was shot with a new load in a new gun 100 rounds down the tube is all
This is 1500 yards shot on the bottom hit first. Came up .2. next was the one just off the edge. Shot was called low right came up .1. next 6 were all in a line. It was a gusty day 2 shots landed off the left edge the next 4 walked right as the wind died. As you can see the 4 in a row we're all in line with elevation. With 2 shots landing next to each other.
This is why .01 grains matter along with brass prep.
If there was .1 grain deviation it would show in vertical stringing.
The reason I started caring about exact loads is the years previous with high and low misses due to SD
View attachment 452254

Well you need not answer my question here.
But answer the question to yourself.
How many times have you shot at 1500 yards?
And are the results always the same, assuming conditions are the same or similar?

 

[lowdowndirtybugger]

Well you need not answer my question here.
But answer the question to yourself.
How many times have you shot at 1500 yards?
And are the results always the same, assuming conditions are the same or similar?

The real question is when an I not shooting 1500 yards and why is it that I take extra care in building loads

 

[yobuck]

Well this is a long range hunting site, and long range shooting goes hand in hand with that.
Frankly, many of the long range hunters arent much interested in group shooting other than working up a new load.
They will send a few at a 100 yard target before the season simply to check the zero on the scope.
Then they are apt to send a few at some distance to get themselves back in shape so to speak.
That of coarse is as a rule not a good thing to do by most serious target shooters.
Loading is another thing many hunters take a more casual approach to.
Mind you now, on average chasing records in the long range shooting game is much like a cat chasing its tail.
But fact is that those who hunt long range are much more successful.
Careless about important things like weighing powder charges to the tenth of a grain or not.
And like it or not, thems simply the facts.

 

[ranger3]

One hundredth of a grain? Really?

Agreed the vertical will tell the story at 1k.

 

[Huntnful]

I just got an FX120i and don't really know how I feel about it honestly. I verified quite a few charge weights that I had thrown from my .1 powder thrower. They were all within .03-.04gr.

So a .8% maximum deviation on a 60gr. charge and .5% maximum deviation on a 90gr. charge.

So for the 30 cal 90gr. charge, that has the potential for a 1" vertical deviation at 1000 yards based off 198" of drop and 2.75" deviation at 1500 yards based off 546" of drop.

I think I'll still weight my long range hunting loads to the .01 but wont waste my time on much other stuff.

 

[Beluebow]

This is why .01 grains matter along with brass prep.

Do you think .02 grains would have made a difference? That load is extremely flat for 1500yrds, I would also assume very wind sensitive as well?

 

[ImBillT]

I showed you the basic math. I explained where and why it can make a difference. Another on here showed where it actually matters in closer range patterning.
If you choose to sloppily throw loads that's your own business.
I'm not trying to convince you of anything

2800/40=70 is sound math, but the relationship is not linear. Looking at load data for H4350 Hodgdon is showing 49fps per grain. Some other powders showed similar results. 4.9 fps per .1gr is not a long way in absolute numbers from 7fps per .1gr, so perhaps there's some basis for a benefit to being more precise than +- .1gr with your powder charges. According to the load data +- .1gr should actually keep you under 10fps SD(which I'm doing). +-.02gr should keep under 2fps SD. Are you achieving that? Most of my shot strings are single-digit or very near in the one gun that I've really tried to get a load that would do that in. Because it's a 51.2gr load, it's likely a little less sensitive than a 6.5CM sized cartridge using around 40gr.

I've never had a scale that read to such precision, but with scales that read to .1gr, they are rarely particularly accurate down to the .1gr. I suppose any scale could be made to read to .02gr even if it were no more accurate than a scale that wasn't even accurate down to .1gr. But I also suppose that if some scale that reads down to .02gr happens to be more accurate than some other scale that reads to .1gr, then the more accurate scale would be of some advantage however small.

I don't consider my +-.1gr loads to be sloppy by any stretch if the imagination, but I don't shoot a mile. I guess getting your SD under 10fps would be of some advantage at that range. I haven't shot past 1000yrds, and haven't shot passed 500yds in quite a few years.