How critical is measuring powder to .01 grains

[dragman]

Wow, I would drive myself insane trying to chase down .01 differences. I thought it was bad enough chasing .1 changes. Usually when I test loads I go in full grain increments, then split to .5 grain. I hear BR guys are nut jobs like that. LOL

Thats why I have stopped, I think most times we completely over complicate things!

 

[Kevin Thomas]

No, actually Benchresters don't weigh their charges, they throw them. Powder varainces are kept to a minimum by the quality measures they use, and most of all, by learning proper, consistent technique in throwing them. For their purposes, what little weight variance remains is absolutely meaningless on target.

Long range competitors weigh their charges, whether we're shooting Benchrest or prone, simply because at these distances, it does make a difference, and you can't run a measure to be as accurate as a properly weighed charge. Match the technique with the game.

 

[Dr. Vette]

Id say the gempro has a resolution of .02 but actual accuracy is probably closer to .05 - .1 from a week to week standpoint.

I find that the variance improves if you leave it running all the time.

Now, having said that, if it's going to be a couple of weeks or more between loading days I shut it off.

 

[Canadian Bushman]

I find that the variance improves if you leave it running all the time.

Agreed.

 

[Rockbottom]

Using some data from a Hodgdon Manual: changing the powder charge from the minimum 55.5gr to the maximum 59gr added 159 fps to the mv to a 125gr Nosler in a .264 Win Mag. That works out to 0.454fps for a change of 0.01gr. of H4831. A ballistic calculator shows the change in bullet drop at 1000yds is 277.15" vs 277.24" if the 59gr charge is off by 0.01gr. Your results may vary.

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[Wachsmann]

If it havent been said your neck tension will change the load way more than a 1/10 of a grain.

 

[Doom2]

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.

 

[338 dude]

+1. Except I use it for every charge.

Same here. Every charge is dispensed with a charge master then goes across a lyman scale just to be sure, and they rarely disagree.

 

[TBell]

Am guessing he was confused. Some people think .01 = .1.

Maybe, plus if you were to get to .01 you would have to get to the point of actually splitting actual 'grains' of powder, when 2-3 grains of rod or tub powders can change the scale by a .1 of a grain.

 

[kfreeze]

In the forum the accuracy nodes in a ladder test range between 1 to 2 grains With accuracy stable in that range. If that node is between 60 to 61 grains, and you decide to load 60.5 grains why is loading to .01 grains critical?

Time is better spent finding wide nodes, bullets that the barrel naturally likes at any seating depth, Than being that concerned with that kind of powder charge differences. IMHO

 

[flintlock hunter]

In my '06 57.0 grs of IMR 4350 is 1 1/4" @ 100 yds, but 57.5 grs is 1/2". (165gr Barnes TSX)
Every gun is a law unto itself.....you have to try it to know.

 

[sturner]

.1 to .01 is a rabbit

 

[highfinblue]

.1 should be fine I would think, has been for me, but it's really hard to say just how much difference that makes as when I got serious about it and bought a new scale I was shooting custom rifles, NF scopes, good rings and bases, excellent triggers, excellent components, so all of that comes into play as well. With all that said 1000 yard steel is easier to hit now than a 300 yard target 30+ years ago, something is making a difference lol.

 

[Randy Tidwell]

BrentM, it is rare to see BR shooters weighing charges. Most of use a quality measure.

I purchased a bunch of test tunes and weighed a bunch of charges. Took them to our tunnel, shot 5 groups with them and 5 groups with thrown charges. The agg with the thrown charges was actually better, not by much. Prob more shooter error.

Get a good quality measure like a Harrels and put the effort into case prep and steering the gun.

JMHO