How critical is measuring powder to .01 grains

[Lenny Foffa]

For me .1 of a grn is necessary and important. In 100 yard bench rest shooting my load needs to be exact , and .1 is an error you should not tolerate! Weather your load is 49.5 of something in your 6 BR or 67.3 grns of H 4831SC in your 270 Weatherby , then that is exactly what you need. Controlling this powder charge to an exact number , is just one part of making a load suitable for the highest degree of precision. Matched cases to an exact weight; Matched bullets to an exact weight, and Base of Bullet to Ogive length, and Base of Case to Ogive Length in a completed round, are other measurement that are also, in my opinion , necessary. Inside neck cleaning is important. Proper neck turning is another thing that MAY be necessary, in some cases. Put all together, these steps and measurements make the finished round more precise. Speaking for myself, every measurement is important, and if it makes your target loads more precise, then why not use the same care and concern in your hunting loads. Yes, a 1/10th of a grain is important,... to me .

 

[glide]

I'm just getting into reloading, but haven't actually started. So I read all sorts of things and posts like this are of great interest to this noob. I once bought 3 boxes of some high priced ammo that I no longer have the gun for and its ammo that even when I try and sell for a fraction of what I paid, cannot find a buyer locally. No more buying that high priced ammo, going to reload what I need. So while I try to get setup, I read....

 

[Muddyboots]

Thanks I am loading 270wsm and 300rum. .1 of a grain should be sufficient

These are hunting cartridges not BR. Hunting bullet weight and ogive variances alone is a bigger rabbit hole. Toss in all the other associated hunting factors and 0.1 is much easier "target" to hit.

Time for another coffee.

 

[leo williams]

If you want the ultimate accuracy in powder charges, the Promethieus is where it is at. +/- 1 kernel of powder....every time!! Salty, but perfect. The time I save over a year of reloading for benchrest competition, pays for itself in speed and my peace of mind.

 

[Pudgy]

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?

Once I started using a SuperTrickler and loading to +/-.02 it tied my whole process together. Now I regularly get single digit SD and low ES.
I now have confidence if something is off it's not the powder , it's some other part of my process.

 

[Starbuck]

I used to worry about small variances like that, but I no longer do. When trying different loads, I usually work up or down by 1 grn increments. I used to measure each charge, but now pretty well trust a thrower with a few QC measurements here and there. The thrower I currently use is an older model Lee that feels and was cheap, but it throws a very consistent charge.

I've found that seating depth and neck concentricity are more impactful than .00 powder variances. As has been stated, I try to chase atmospheric consistency more than absolute accuracy. I should qualify my statements by including my use and expectauons. Use is long range shooting to 1k for fun and informal competition, and hunting to 600. Expectation is ~ 1 moa for 10 shots.

Certainly, different uses will drive different procedures.

 

[MKWas]

Accuracy vs Precision. In metrology the two terms mean very different things. It is important to know both.

Accuracy is how close a measurement is to the real value. If you have a 100 grain weight does your scale actually read 100 grains? since there is some variation you need to take multiple readings & average. A scale that measures 100 3 times is as accurate as one that measures 90, 100, 110. One that measures 110 3 times is less accurate than the other two. For a first pass, a scale that measures to 0.01 gr is 10 times as accurate as one that measures to .01 gr. Maybe!

Precision is how close repeated measurements are. For the examples above: the one that measures 100 3 times & the one that measures 110 3 times have the same precision, the one that measures 90, 100, 110 is least precise.

So what you really want is precision - reload with the same load with the same equipment and you have repeatability. You can't ignore accuracy, but as long as you are within +/-0.1 grains you are probably OK especially for most rifle loads.

An easy thing to do is to get a box of representative bullets:
- Measure a bullet repeatedly, is it always the same?
- Try several - they won't all be the same weight but most should measure the same weight every time.
- Some will be not measure the same every time. These are bullets actual weights are between what can be displayed - if your scale measures to 0.1 gr then that means the bullet's weight close to xxx.05 gr. The fluctuation indicates precision. I wouldn't expect any to measure 3 different weights.
- Repeat several times.

Evaluation:
- If you have any bullet that reads 3 different weights then the scale is highly suspect. That is, if you get readings 99.1, 99.2 & 99.3 on the same bullet then the accuracy is highly suspect. I wouldn't trust that scale.
- The fewer bullets with weight fluctuation the better your precision.

This gives a subjective evaluation. Anything more requires expensive equipment & specialized expertise.

You may want to keep the bullets that have variation. See if you get the same results under different conditions - like low charge/batteries, different ambient temperatures.

 

[yobuck]

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

Actually, not all of them at least are.
Go to a varmint class match sometime where many of them will reload the same cases between relays.
Everything is important, but sorting cases is something most of us never even consider.

 

[wldcat]

I wasn't going to post, but I just couldn't help myself. I feel different then most of you and I would weigh to .00001 if it was possible. Now I don't think I need to but I try to control every aspect of every load for the absolute highest precision possible, when I miss it has to be my fault!!! If I ever suspect my reloads of causing a miss the what's the point of reloading? Might as well buy factory ammo it sure would save me a boatload of time, takes 4-5 hours to load 50 for me with all the checks and balances but I do end up with loaded rounds that are within.1 gr…..

 

[Lenny Foffa]

Yes Sir , Thats why I used the words Precision and Precise, not accuracy . Many years ago I began sorting my 270 and 30/06 cases by .5 gran increments In my Weatherby Mag cases by 9/10of a grn So I have boxes of 270 Weatherby Brass that are labeled 195 grn. Range and 196 Range . I have ended up with 7 or 8 Blue boxes of 270 Win Brass, as well as some zip lock bags of outliers. . I happen to enjoy this process, and It makes me feel more confident when I go to the range, or the Box Blind. Also I only need to sort the Hunting Load brass by 1/2 grn increments once. So although one thing alone may not have a great effect of the load, all the steps put together seem to result in a more PRECISE load. IMHO

 

[Willys]

With my autotrickler it weighs to the kernal every time as fast as I can seat the bullet - about 10 seconds.
A kernal of n570 is .08 grains so I end up within .04 or +-.02

 

[Teri Anne]

Weighing powder to 1/10 is adequate for any application. You'd drive yourself insane trying to weigh to 1/100. With your example of the node being between 60 and 61 gr, some may load 60.1, 60.2, etc, as a tenth of a grain can make a difference at 1k yards. Hundredths? No.

Been reloading for a long time and in the grand scheme of things 1/10th of a grain might not mean that much at 1000 yards, I pretty much only shoot out to 600 where it doesn't seem to make a difference, but as a matter of course I do weigh all charges going into rifle cartridges to the exact charge. Pistol ammo once the charge is set I only drop the charges checking every 10 or so to make sure that the charge weight has not changed. Why the difference? Primarily because at the distances one is shooting a pistol and the variations with the hold and sight alignment 1/10 gr, even at 50 yards will not make a significant difference in the flight path of the bullet, but the shooters position, sight alignment even with a scope or dot will not be so steady as to compare with a long range rifle shot off of a bench.

Now let's throw a monkey wrench into the calculations. When we do a ladder to check the accuracy we do our variations in either 1/10th or 2/10 grain intervals. This is done to find the ultimate combination of powder vs bullet that shoots the best out of our rifles. If our rifle, as an example my 308 loads absolutely love 40.5 grains of IMR4320 and 165 or 168 gr bullets. They both shoot sub MOA with this load and are good on targets out to 600 yards. If I vary the charge by 1/10th of a grain the groups open up and may exceed 1 MOA. With IMR4320 out of production I am going to work up another load, most likely IMR4350 but that is yet to be seen.

In the end it is all up to you and your rifle. If you take the time to work up a ladder for the rifle then it should be worth your time to measure out each cartridge to obtain the best accuracy for your rifle. If you get lazy and only throw the powder and allow variances then expect the groups to suffer.

 

[Lee7588]

When considering a powder charge with a .01 grain difference, what do you accept for projectile variable?

 

[5280Reloader]

I try to be very consistent with my loads. My mindset is changing a little but I have been known to get that detailed with it.