Powder dispenser deviation between charges

Summing up the good advice you have received above......A really good powder measure isn't cheap but is a must. Also, all of them must have a baffle installed. Some powders measure better than others. Your operating technique must be as exactly the same every time as much as you can master. Then the point I want to make......a slight variation in powder weight from cartridge to cartridge has about the least affect on accuracy of all the myriad of variables in putting a batch of reloads together. Caution must be observed when using very fast burning powders in small cases. Also, when loading rifle cartridges to the very max. The best accuracy for any loading is always obtained some where below maximum load. There are always exceptions to every generalization. You need to read everything you can about reloading. Some of the published books and articles should be read multiple times.

One last bon mot: Reloading is a situation where the Law of Diminishing Returns comes into play quite often and quickly.

A second bon mot I just remembered: Every firearm is different in small ways from any other. The individual firearm is a law unto itself when accuracy is the goal.
 
Try using a baffle in side the powder reservoir to maintain a constant head over the measuring cylinder. You can make one easily out of cardboard. The best way to get charge consistency.

I have two Lyman 55 measures. I set them by throwing five charges and dividing by five. i.e. I if I want a five grain charge, I set my powder scale at 25 grains, then throw five charges. Adjust the measure until you throw five charges which weighs 25 grains.
 
Rule3 said:
FORGET the "average" method of 10 drops
It is meaningless. An average is just that an average. What if one drop was 6 and then one was 7 etc. The average is not what is in each case.The average would be 6.5 but one of those (6) would be an undercharge. If you do an average of 100 or 1,00 then you could have several that are way (weigh) off.


As mentioned weighing out to 1/100th of grain is also meaningless

Especially with a SLOW powder like Long shot. 6.9 or 7 or 7.1 you will not know the difference.

Don't get hung up on stats, SD and all that stuff.

Drop a powder charge weigh it, pour into a case, repeat untill you know what is going on. LOOK into each case to ensure the charge is in there.


Before someone with no actual experience(with it) whines about the LPPM. It is actually VERY accurate and doesn't leak(I tested it long ago with many powders and recorded ever drop. With stick powders it was better than my RCBS. Uniflow.
Click to expand...


In theory you're correct, but how likely is it that a powder measure would be that far off? Especially as you say the LPPM is very accurate.
 
Think of it this way. A +/- 0.1 grain deviation for a 5 grain pistol charge is only +/- 2%. For a typical 40 grain rifle charge, it represents far less than 1% (actually 0.25%).
 
Jwjarrett said:
Can someone post an illustration, picture or link to a baffle?
Click to expand...

This 3-minute RCBS video [ame="https://www.youtube.com/watch?v=dKbLxq2UrXw"]RCBS Video[/ame] shows a powder baffle, but does not say much about what it does.

The main function of the baffle is to keep the weight above the actual powder flow relatively constant, even as the overall powder level falls. That helps maintain uniform powder density and flow rates.
 
With the load you mentioned, .1 grain deviation isn't much and won't be a problem. However, if you later start loading a really fast powder in a small caliber such as .25, .32 or .380, your powder charge could be very small. A .1 grain deviation could be a problem. As an example, .25 ACP with a 35gr jacketed bullet and Titegroup starts at 1.5 gr with a 1.7 gr max according to the Hodgdon web site. Size matters.
 
As stated above a baffle & consistent technique helps a good bit . Ball powders are the most consistent when you're dispensing by volume , next would be short grained extruded like Vihtavouri powders , long grain extruded & larger flake powders are the hardest to get consistent drops with . Best to set measure to throw just short of your desired weight & finish off with a trickler . Like scales a good powder dispenser aint cheap . Consider that benchrest rifle shooters use thrown charges & you won't find their loads in a manual either , some are eyebrow raising . Most use Harrell powder measures that are extremely precise with selected propellants , but they are costly .
 
Jwjarrett said:
I have been measuring with the balance and a small digital. The digital and balance are spot on with each other to the 1/10. Of course the 1/100 is an estimate on the balance. I grew up on vernier calipers, so I read the scale similarly.
Click to expand...

Estimates? You have a scale, it gives a weight, there is no estimate. To get 1/100th grain, you would have to tjrow 100 charges & then avg them. Again, even if you had a scale that accuraye, means nothing. Internal case volum varies as much as 3-4gr deoensing on caliber.
 
I ran some throws using as many of the tips as I could. I made a baffle out of cardboard similar to the one in the RCBS video (Thanks Twoboxer - is that your P51?) I practice consistent throws, zeroed my scales, added powder to 3/4 full. The first run produced throws that average 7.3. (7.27 on the digital) Max was 7.36 by the digital, minimum was 7.21. Most were 7.25 to 7.28. Bottom line with the baffle is that it was more consistent than yesterday.

Without the baffle with all other things equal, the throws were higher, averaging 7.60. Most were consistently 7.56 to 7.62.

My take away was a loaded bottle without baffle can result in consistently heavier loads - 3 grains heavier in this case. Both seem acceptable consistent with a full hopper but I would expect the non baffled to start out heavier and creep toward lighter as the level in the hopper decreased. I would expect the baffle to dampen this unless the powder level ran below the baffle.

Another thing I paid attention to this time was the uniformity of the powder. I would assume the smaller flakes could settle causing denser loads.

When my primed brass gets here, I'll be watching the powder and being very picky on the first few hundred until I can be comfortable. Maybe then I reduce to measuring every 10th.
 
Back in the good old days, before we had baffles, we just refilled the powder hopper more often, as in when the level dropped to half full, add powder. This resulted in a fairly consistent downward pressure on the powder at the bottom of the hopper. The baffle accomplishes the same thing, you just don't have to keep the volume of powder in the hopper as consistent.
 
Jwjarrett said:
Can someone post an illustration, picture or link to a baffle?
Click to expand...




You do not NEED one. Just keep the powder measure (any brand) at least 3/4 full.


The powder measure is just a "hole" it fills if you have a baffle or not.


More depends on the Powder type. Long Shot meter very well as is it "fine" other flake powder like Unique not as well.
 
Jwjarrett said:
I ran some throws using as many of the tips as I could. I made a baffle out of cardboard similar to the one in the RCBS video (Thanks Twoboxer - is that your P51?)

No, but she was "mine" for an hour lol . . . and then only from the back seat of that modified P51C. Couple years later I flew back seat again in "Toulouse Nuts", a modified P51D. Those flights took the next to last thing off my To Do bucket list.

I practice consistent throws, zeroed my scales, added powder to 3/4 full. The first run produced throws that average 7.3. (7.27 on the digital) Max was 7.36 by the digital, minimum was 7.21. Most were 7.25 to 7.28. Bottom line with the baffle is that it was more consistent than yesterday.

Without the baffle with all other things equal, the throws were higher, averaging 7.60. Most were consistently 7.56 to 7.62.

I'm going to assume that your digital scale isn't fluttering around and constantly losing zero due to RF noise or other causes. While likely not enough throws for "proof", you've got enough data to see the trend now. With consistent weight above the flow port and consistent technique, throws will in fact cluster near the average for your run. For handguns, this is good enough for almost if not all shooters.

My take away was a loaded bottle without baffle can result in consistently heavier loads - 3 grains heavier in this case. Both seem acceptable consistent with a full hopper but I would expect the non baffled to start out heavier and creep toward lighter as the level in the hopper decreased. I would expect the baffle to dampen this unless the powder level ran below the baffle.

Another thing I paid attention to this time was the uniformity of the powder. I would assume the smaller flakes could settle causing denser loads.

Smaller flakes will, but the irregular shape of that flattened ball powder will *also* allow edge-to-edge bridging . . . until its "weight limit" is exceeded. And that effect will vary due to the irregularity.

When my primed brass gets here, I'll be watching the powder and being very picky on the first few hundred until I can be comfortable. Maybe then I reduce to measuring every 10th.
Click to expand...

I've found it easier to set my target throw weight by 1) adjusting the throw meter, 2) throwing 2-3 charges and returning the powder to the measure, 3) throwing 10 charges into a tared pan, and 4) looking for (eg) 69gr on my digital scale. Rinse, repeat. Otherwise, I find myself chasing the variation instead of the target. Just a thought, YMMV.
 
Last edited:
Jwjarrett said:
I ran some throws using as many of the tips as I could. I made a baffle out of cardboard similar to the one in the RCBS video (Thanks Twoboxer - is that your P51?) I practice consistent throws, zeroed my scales, added powder to 3/4 full. The first run produced throws that average 7.3. (7.27 on the digital) Max was 7.36 by the digital, minimum was 7.21. Most were 7.25 to 7.28. Bottom line with the baffle is that it was more consistent than yesterday.

Without the baffle with all other things equal, the throws were higher, averaging 7.60. Most were consistently 7.56 to 7.62.

My take away was a loaded bottle without baffle can result in consistently heavier loads - 3 grains heavier in this case. Both seem acceptable consistent with a full hopper but I would expect the non baffled to start out heavier and creep toward lighter as the level in the hopper decreased. I would expect the baffle to dampen this unless the powder level ran below the baffle.

Another thing I paid attention to this time was the uniformity of the powder. I would assume the smaller flakes could settle causing denser loads.

When my primed brass gets here, I'll be watching the powder and being very picky on the first few hundred until I can be comfortable. Maybe then I reduce to measuring every 10th.
Click to expand...
Again, what scale are you using that measures 1/100 gr? 7.25 is 7 & 25/100 gr.
 
stansdds said:
Back in the good old days, before we had baffles, we just refilled the powder hopper more often, as in when the level dropped to half full, add powder. This resulted in a fairly consistent downward pressure on the powder at the bottom of the hopper. The baffle accomplishes the same thing, you just don't have to keep the volume of powder in the hopper as consistent.
Click to expand...


I started with Lee dippers. If used correctly they are as accurate as a powder measure.


A "hole" is a hole:)
Volume measure is the same with a dipper of a hole in a powder measure.(once that volume is determined by WEIGHING! Dip and use a straight edge over the top, Do not shake or stir.
 
fredj338 said:
Again, what scale are you using that measures 1/100 gr? 7.25 is 7 & 25/100 gr.
Click to expand...

Fred, I have a small jewelry scale along with the balance scale. I'll be rounding to the tenth when throwing loads.

All you guys have been very helpful in teaching me the degree of accuracy I should strive for on regular reloads! I appreciate it.
 
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