How accurate do you weigh powder?

F

fshfindr

New member
How much tolerance do you allow yourself when weighing powder? As an example, if you are going to use 20g of powder, do you accept only exactly 20 grains or will you settle for 20.1 or 20.2 or maybe 19.8 or 9? I'm using some 50g SPBTs with 22.0g of H322 and 62g SFPBTs with 20.5g of H322. I have been allowing +- 0.20g tolerance for .223 semiauto. So how will that effect my accuracy at 100 yds?

Thank You for all comments.
 
What I always say, is get as precise as you can repeatedly, efficiently (time is involved here) get. If your scale charge throwing combo allows for .02 accuracy, but with taking3 times the time involved than taking it to .1, why bother. Me, I'm picky. But my scale is only in .1 increments (may change when my grandpa sells his lab, I wanna snag an analytical balance, .002 grain accuracy) so I take it to .1 grain, as well as my eyes (not so old) can line up the lines on my old beam balance. It's a tricky act.

On the accuracy effect of .2 gains. I have seen major group changes in .2 grain increments. I mean from 1.25 inch groups, to about .5 inches. That's at 100, with only .2 grain difference. Now if you're doing +/- .2 grains, one could be 2 under, and the next 2 over. That's s pretty huge difference. But, if you're just blasting away, taking buddies to the range and shooting up beer bottles (soda cans for those under 21) then hell, keep your .2 grain tolerance

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To me, a weighed chart is exactly the desired weight, such as 41.5 grains plus or minus nothing. This assumes the scale is accurate, which ain't exactly so, everything has tolerances, but I ignore the scale tolerance. Out to three hundred yards I am skeptical of the benefit of weighed charges. Most of my 308 Win target loads are thrown on a Dillion 550B. It is my recollection that thrown charges are plus or minus a half grain, at best. With IMR 4064, a long stick powder, the charge variance has to be plus or minus a grain. I don't remember exactly, but long grained powders throw much worse. I can say, I have shot lots of cleans out to 300 yards with thrown powders.

With maximum loads, I weigh. I cannot prove it makes much a difference. I shoot my maximum charges at 600 yards to get the maximum velocity at that distance. While I have shot close to perfect scores a number of times at 600 yards, what has cost me points or a point are wind changes. I failed to catch the wind change and did not read the wind indications correctly. So, the longer the distance, range conditions are far more important to putting the bullet in the center. I have shot a number of excellent scores at 600 yards with Dillion loaded 223 ammunition. I used the 75 Hornady with N140, a short grained powder and the charges were thrown by the Dillion powder horn. After shooting a couple of 197's with Dillion loaded 223 ammunition, it can be very hard to convince one's self that weighed charges do much of anything.

National records have been shot with Federal Gold Medal match, and that ammunition has thrown charges. Just reload to your psychological level of happiness. If you cannot sleep, tossing and turning because your powder charges vary by 0.1 grains, than keep the variance to 0.0.
 
The closer the better, even said, if your powder is exact in 10 cartridges you will get 10 variable readings with the chronograph.
 
Are you double tapping the handle on both the up and down strokes. You need to be consistent in how you move the powder measure handle. Double tapping makes certain that the measure is full and then double tapping makes it all come out.
 
Accuracy is a combination of several factors. If you don't measure, maintain tolerance on all of them, I fail to see one being more significant than the other. Now not all components need to be within .1 gr. But, for example, why weigh charges to exacting values if you are not weighing cases (some will argue case capacity)? Case weights can vary easily by 10-15 grains depending on the cartridge. With that much variation why bother with .1gr of powder. I personally don't think .1 gr makes a difference unless you are loading charges below say 20gr. Too many other factors including scale tolerance. I question .2 grains but one of the posts states 1.5" - .5. That's dramatic and in my experience very unusual. I work loads up usually in .3 gr changes and even with .3 gr I've never seen that much of a difference. Look at Dan newberrys optimum charge weight.
 
I have been using the RCBS ChargeMaster 1500 accuracy +/-.10 of a grain. Let's say your loading 41.5 my way of thinking it could be 41.4 to 41.6 bought the GemPro 250 to double check take the load from the CM which is fast & dump it in the GP. The GemPro is exact. The CM is more then +/- .10 for accurate loads check out the GP 250 glad I did.
 
I want my powder charges to be as accurate as possible. Less variance, more accuracy. As I don't shoot/hunt with my rifle's as much as I use to, I sold my RCBS ChargeMaster recently and use my Ohaus 10-10 scale. Pretty much for my .38spl and .45acp. Some for 30-30, 270 Win and 30-06. Just for target stuff. I'm mostly into shotgunning now[upland birds]. But, when I handload, I want accuracy. Just my thoughts.
 
When you've found your best load, try varying the charge to see what error it tolerates before it doesn't shoot as well. Aim your future loads at the middle of that tolerance range to try to keep things as unlikely to be outside it as you can. That gives you some wiggle room when you are dispensing powder for producing a quantity of ammo. At that point you may find a powder measure is accurate enough to stay in tolerance.

Personally, I reject a load that doesn't tolerate some charge error, as it's more likely to be temperature sensitive.
 
Some powders I have found(Unique is one of them) seem to shoot better by volume than by weight. Thus a variance of .01-.02 either side of the target weight doesn't matter as long as volume is the same. When I used Trail-Boss, I found that once I found a load and used a homemade dipper, the ammo was more accurate than weighing each charge separately. Like Unclenick, I tend to shy away from powders that are sensitive to very slight differences in charge, as they tend to vary more between batches, even if one takes care to keep things the same.
 
The significance of tolerance depends on what percentage it is of the target weight. .1 grains off on a 1.0 gr load for 25acp is a lot more significant than being off by .1 gr on a 24gr load for a 44 magnum.
 
20.1 is a different load. Even 1/10th of a grain(that is .1) is enough to make the difference between a one hole group and just a group.
Not weighing cases won't affect accuracy.
 
Not weighing cases wont affect accuracy? Case volume will absolutely affect accuracy. You can argue case weight is not an accurate assessment of case volume, but case volume/weight will affect accuracy.
 
I try to stay within 0.1 of my target charge because that's the limit of my scale. A recent thread on THR noted that a 0.1 change in charge had little effect on chronograph velocity and a change such as 0.5 was needed to make a significant difference. I would also note that bullets often vary quite a bit. I just today weighed a few of my 124 grains from Berrys and found ten bullets varied from 123.9 to 124.4 grains. So if you're not completely OCD about absolute accuracy, in which case you should be weighing bullets, why bother staying under 0.1 grains of charge variation?
 
One of my best scales is an old Lyman M5 made by Ohaus. What do I like to see? I am content with +/- 0.1 grain which is the uncertainty of most scales used for reloading. What I want more than accuracy in a scale is good repeatability. If for example my target weight is 42.0 grains of IMR 4064 I really don't care if my actual charge is 42.0 grains but I want it to repeat charge to charge. If my 42.0 grains is in reality 41.7 grains I want all my charges to be 41.7 +/- o.1 grain or better.
I have seen more change in primer to primer than a powder drop of 0.2 grains or more. While I can't control primer to primer I can stride for repeatability in my powder charges. Today I use a RCBS Chargemaster and see no difference than hand weighing each individual charge using a trickler. Maybe some can see a difference with +/- 0.1 or 0.2 grain, I can't. I just want uniformity and repeatability.

Ron
 
0.1 for me too. I have an RCBS Uniflow powder measure, some years ago I put their baffle in it. That seemed to make a noticeable difference in stability and consistency.

I use a Dillon 550 for handgun, used to use it for .223. It throws charges extremely consistent in handgun and ball powders. Never would use stick powders in that one except IMR 4895 and similar "short stick" powders for which it did ok.
 
I'm willing to accept a 0.1 gr variation (throw all loads by hand and measure individually).

That said, I have plenty of loads where the difference between reliably cycling and not cycling is 0.1 gr, so I often bump the load up by 0.1 gr if I'm loading on the low end of the range. That way any variation in thrown load doesn't affect reliability.

Really wish I could find an electronic scale that's reliable without having to constantly rezero. I've tried several but still keep coming back to the RCBS 505 because I trust it much more in terms of accuracy and repeatability.
 
Like UncleNick and buck460, I won't tolerate a load combination that has a narrow "sweet spot" between shoots poorly and shoots great. I throw all of my charges for rifle and pistol, including the 600-yard ammo I used to shoot in Highpower. Path of least resistance and all, like Slamfire wrote, when you shoot good scores with ammo that took less time to load, it's follow a process that it more intensive.

As an experiment, load 3 rounds at load X/, 3 rounds at X-.1 and 3 at X+.1 (weighed and trickled). Then load 9 rounds at X as thrown charges. Now go shoot them all over a chronograph and for a group. If they don't all go to the same POI and have a similar extreme velocity spread, I'd be very surprised.
 
In all the years I've been a home reloader I've never felt the need to make those all perfect cartridge's which require tight tolerances, stringent measurement of powder, and components. Never been keen on doing such reloading.
As a matter of fact I'm one of those who have continually push the envelope for all his cartridges to attain their very most velocity and coincide with best groupings. BTW: Which requires the use of different powders experimentation to find those non-published higher velocity's and such accuracy.
So's y'll know. What I do is dangerous. Its also rather expensive. Powders buying and burnt out barrels are a certaintee. My firearms are simply tools for my use. Never intended for heirlooms. If I wreak one I have it professionally fixed or go buy another. Which ever is easiest.

(I do not promote others to follow suit.)
 
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