+ or - 0.1 Powder Charge

[mrbill2]

Does increasing or decreasing your powder charge by one tenth of a grain realy make a differance. Seems to me you could burn up a lot of powder playing with one tenth of a grain. Don't know that I can shoot well enough to even know.
Mr. Bill

[Heavy lead]

Depends, on some rifle cartridges 50 some grains and up .1 grain wouldn't even be noticed on a chronograph. If you are talking 3 grains of bullseye it could make a huge difference. If you are asking about accuracy for rifle cartridges for medium to large cases (ie, 22-250 up through416 Rigby) I usually accuracy and pressure test working up in .5 grain increments. For 222 and 223 I will go .3, handgun is a little different for me. Never have loaded much more than middle to middle upper loads, so never have I worked up a load to maximize velocity and accuracy.

[Treeman]

Actually, even in handgun cartridges and smalll charges .1 grain usually makes less difference than shot to shot variations of all the same charge .1 higher or lower. (Thats what my chronograph indicates) That doesn't mean that precision is unimportant or that we can blythely add a smidge more powder to max charges but we need to maintain perspective..1 grain is 2% of a 5 grain charge. 2%, statistically tends to get swallowed up in the variables.

[Char-Gar]

Oh, I don't know as I have never done it in 49 years of handloading. I usualy quit tweaking at the .2 or .3 grain stage as I have found a good load by that time. That doesn't mean there isn't some value in the .1 grain thing, but I doubt it amounts to much.

[missionary5155]

Hi there Mrbill2 WELCOME !!!
When I was developing my 41 mag load to shoot steel I did try increases of .5 grain until I found The best load... then I switched to .1 grain and found THE BEST load with that bullet. But with everyday loads for revolver I use mostly Unique and .5 is close enough.
Rifle... .5 grains is the smalest increment I use with bottleneck. With the inicial load 1 grain at a time... even when I am using Unique. I do NOT use a faster powder than Unique in rifle.

[garandsrus]

Serious benchrest guys drop charges that may vary by .1 gr and don't seem to care at all....

John

[Scrounger]

If you have ever chronographed loads or read loading data from a ballistics lab, you can see pressure and velocity variations even from weighed charges loaded under laboratory conditions. These variations are far greater than one would expect from even 3% powder charge variations. A .1 grain variation in a 20 grain charge is .05%. I remember reading an article years ago from a very respected gun writer that he used 1/2 grain increments in charges under 30 grains, and 1 grain increments in charges over 30 grains. One grain variation in a 30 grain charge is about 3.3% change; in cases like the .30-06 where powder charges typically run between 50 and 60 grains, a 1 grain increment is less than 2%. Works for me. I think weighing charges to .1 grain is being anal to an excess.

That being said, if you are involved in any form of competitive shooting, if weighing your charges to such a degree gives you more confidence and you think it is better, then it will be better. The mental condition is the biggest factor.

[Three44s]

There is too much obsessing over .1 grain charge increments ........

I don't get that anal until I find a SWEET spot ..... then work in around to the nearest .1 grain ....

BUT whenever I can .... I try to develop loads that can be thrown as opposed to having to be weighed!

So it comes down this ..... if you have an intense desire or a stated reason to weigh .... then do so ........ otherwise ...... so long as it's safe ......... THROW!

Three 44s

[Scrounger]

And... About 40 years ago when I started loading shotshells, I remember reading in the Lyman Shotshell Book that it was the volume of powder that mattered, not the weight. A given volume of powder would weigh a little more in the winter time when it was more humid because the powder absorbed water. I believe the absorbing water thing but I'm sure there are places where the humidity is higher in the summer than in the winter. To simplify and accurize that statement, I'd say," The same volume of powder weighs more on some days than it does others".

[compass will]

I am the "new guy" to this cast loading, but i am working on loads for a .308.

I use .5 till I find something close, then load 5 cartridges of each power load and make a .1 grain charge.

I think as you move across a range in .1 grains you see "waves" of good and bad.
Example: I will leave out the powder so I am not posting actual loads.
I weigh each load, then use a dipper to add/remove to make load correct.

.308. 170 grain lee flat nose. Winchester primer. Case sized in lee collet die. Crimped with lee factory crimp die.

5 shot groups, warm barrel, using a Caldwell BR rock on a good bench. Low wind, all temps around 30-40.

weight group
28 1.5"
28.1 3"
28.2 1.25"
28.3 3"
28.4 3"
In this run, if I had only tried 28 and 28.5 I would never have seen this group at 28.2. Why the jump at 28.1? What should I try next, lower then 28? or stick with 28.2?

200 grain lee bullet same powder as above:
28.6 3"
28.7 1.75"
28.8 2.25"
28.9 2.5"
29 2.3"
29.1 2.8"
29.2 3"
29.3 3.25"
I guess 28.7 is good, but should I try lower?

Here a different powder with 170 grain boolit
20.5 3"
21 2.5"
21.5 3"
22 1.75"
Next loads I will take 21.8, 21.9, 22, 22.1, 22.2. But if I don't try .1 around 21 grains I might never know if there is a better group in there?. This same load in a 32 special the books say is around 2000fps. Plus I want to load some 200's. No idea of the speed, but should I also try lower?

This same gun with jacketed bullets don't change must with 1 grain powder differences.

This does point out that my .1 grain increments are showing major differences.
Or is it the shooter? [smilie=1:

[trk]

I don't have a chrono; but I do work up loads.
Simply.
I use 5 shot groups to start with - generally 5 or 6 that are 1 grain appart.
Then I repeat a range around the good groupings.
If it repeats, THEN I come in with 5 groups 0.2 grains apart.
When I can do 5 five-shot groups in a row of (___ insert 1/2" 3/4" 1"___) at 100 yds I know I've got a good practical load.
Others go for first shot from COLD (clean or fouled) barrel.

[44man]

I have never found a need to change by less then .5 gr.
Put it this way, use the best load with .1 gr difference and shoot 10 groups. By the time you get to the last group the humidity, wind, sun or temperature changed enough so you are back to 3".
Put .1 gr powder in your hand and look at it! How can you ever think that will make a load shoot better or worse???? Variations in primers, brass, bullet tension, even fouling in the brass and barrel will wipe that out. Even 1/2" difference in where the gun sits on the bags will change it.
In my opinion, when the tight group was shot, you did your best or you lucked out that the brass, boolit and fouling was the same.
Shoot the super tight group today, with the .1 gr change and go out next week or next month and duplicate it!

[beagle]

Now, I'm gonna stick my neck out here and will probably get all kinds of flak over it.

Sure, .1 grain will make a difference in a very "tight" load for accuracy. The .22 Hornet is aprime example. It's super ticklish over weight variations.

But, can we consistently hold .1 grain tolerance. I seriously doubt it.

Many measure their charges and i'm sure this doesn't hold that tolerance. I drop low and trickle up to my desired weight each and every round I load. Guess I'm paranoid but it's worked for me since 1958 and if it ain't broke, don't fix it.

Am I acheiving a .1 grain tolerance? I seriously doubt it due to equipment (beam scales), temperature, breeze over the bench, vobrations of the bench when you're seating, etc. Just too many variables.

Don't talk to me about e-scales as I doubt they hold .3 grains due to the bvariable above and flourescent lights on the bench which most of us use.

So, my advise is to try and hold the closest tolerance possible and enjoy loading and shooting and don't fret over .1 grain unless that's teh "sweet" spot for your load./beagle

[Harry O]

When trying to find the most accurate load for a new rifle, I load up 20 rounds (total) starting 10 grains less than maximum and working up in 0.5gr increments. Then I shoot them at a "T" target and look for a cluster. Then I go back home and load up some more at the load in the middle of the cluster. If the "maximum" given in the loading manuals is more than the maximum my rifle can take, I just stop early.

It does two things at once: (1) gives me a safe maximum in my rifle, and (2) finds the most accurate point for that powder and bullet. You can Google on "T" target and get more information on how it works, but it works. It is the fastest way I have found to find accurate loads.

[beanflip]

My WAG ( wild a-- guess ) I dont think the target, paper, critter can tell the difference.
That my wag.

OH HAPPY THANKSGIVING TO ALL

[Shiloh]

There is too much obsessing over .1 grain charge increments ........

I don't get that anal until I find a SWEET spot ..... then work in around to the nearest .1 grain ....

BUT whenever I can .... I try to develop loads that can be thrown as opposed to having to be weighed!

So it comes down this ..... if you have an intense desire or a stated reason to weigh .... then do so ........ otherwise ...... so long as it's safe ......... THROW!

Three 44s

This sums it up. Even with the sweet spot found, I call it good.

Geez!! The time I wasted and trigger time lost due to fretting about 1/10's of grains. None of my firearms are match grade so it doesn't make a difference anyway.

Now for the bench rest guys or the precision, tight tolerance firearms...[smilie=1:

Shiloh

[44man]

None of the BR guys worry about it either and most never weigh a charge. They use a measure at the bench and if things change on them, they tweak the measure a little. How they tweak is based on experience. I don't think they know what .1 of a gr is.
They use select brass and keep shooting and loading the same brass for a shoot, right at the bench.
If we had to worry about a sweet spot with .1 of a gr, none of us would ever get good groups.
It is a silly concept. Outside conditions wipe out any advantage of loading that tight.
I trickle a lot of powders to the exact amount but only do it because the powder in question will not meter through a measure.
Years ago I thought I would weigh out BP charges for my muzzle loaders. I figured they would be more accurate. Groups really sucked so I went back to my volume measure and shot ragged holes again.

[Char-Gar]

I hate to be the grinch, but somebody has to assume that role. One five shot group is worthless in proving anything. Repeat the same test ten times and maybe you will have some data that might indicate someting of value.

In order for a group to say anything about accuracy, it must be repeatable day after day. Now come on guys, fess us. How many have fired an outstanding group and could not repeat it the same day, the day after or a week after?

[Freightman]

I hate to be the grinch, but somebody has to assume that role. One five shot group is worthless in proving anything. Repeat the same test ten times and maybe you will have some data that might indicate someting of value.

In order for a group to say anything about accuracy, it must be repeatable day after day. Now come on guys, fess us. How many have fired an outstanding group and could not repeat it the same day, the day after or a week after?
Yep well said!

[44man]

Right on the money! :coffeecom
As good as I get my guns shooting and other friends rifles too, it can never be done every single time. What counts most is if you average good groups all year.
Even the suns movement can shift shots if you take enough time for a 5 shot group.
I have to laugh at guys that say they can shoot such and such group "On demand." I will never profess to such a thing.

[mrbill2]

Thanks fellows for all the input. I think I'll wary more about doing things right at the shooting bench than .1 at the loading bench.
Compass Will Good luck at the December match at Atglen. See you in the spring !!
:-D
Mr. Bill

[John Boy]

Does increasing or decreasing your powder charge by one tenth of a grain realy make a differance.
Mr Bill ... No if the powder charge is original gunpowder. Half a grain variance is acceptable. What is critical is bullet weight variance and powder compression consistency

For smokeless, shooting 500yds plus, I work the loads up in 0.1gr increments. Any distance less - No. Half grain increments only

[Scrounger]

Right on the money! :coffeecom
As good as I get my guns shooting and other friends rifles too, it can never be done every single time. What counts most is if you average good groups all year.
Even the suns movement can shift shots if you take enough time for a 5 shot group.
I have to laugh at guys that say they can shoot such and such group "On demand." I will never profess to such a thing.

That is sensible. There are so many variables in loading and shooting that worrying about .1 of a grain of powder is laughable.

[joeb33050]

I believe that powder charges should be in .5 grain increments, the only exceptions (maybe) being very light loads, under ~8 grains.
If the charge is 34.5 grains, that 34.5 grains describes the domain from 34.25+ to 34.75- grains. As a practical matter 34.5 grains covers 34.3, 34.4, 34.5, 34.6 and 34.7 grains. (34.0 covers ... 34.1 and 34.2 grains, 35.0 covers 34.8, 34.9 ... grains.)

When I say that powder charges sould be in .5 grain increments, I'm saying that nobody can tell the difference in accuracy between charges .2 grains away from the nominal. So, for a 34.5 grain charge, nobody can tell the difference between 34.5 and 34.3, 34.5 and 34.7, or 34.3 and 34.7.

In order to see small accuracy differences we need to shoot a very large number of groups, under similar conditions-more groups than most of us are willing to shoot for a test.

I've asked for the data supporting XX.3 or xx.9 grain charges, with no response.

For more on the accuracy and repeatability of powder measures, see: "Cast Bullets For Beginner And Expert", Second Edition, which can be found and read online at: http://sports.groups.yahoo.com/group/CB-BOOK/
The book is in "FILES", the Table Of Contents is in "The Beginning"

See "6.4 POWDERS AND POWDER MEASURES"-down a bit is "The Astounding Powder Measure Test".

In ERRATA see "Reloading Scale Accuracy"

I'd like to hear about any powder charge at XX.Y, where Y is not zero or 1, means that Y is 2,3,4,6,7 or 8; that gives better accuracy yhan the appropriate charge ending in zero or 1.

joe b.

[Larry Gibson]

My initial load development for 30-30 sized cases and larger is in .5 gr increments (sometimes 1 gr for the larger cases). I use 2-3 shots to get velocity and now pressure up to the range I expect the load to perform at. Once in that range I tweak the load in .2-.3 gr incrments looking for accuracy along with the velocity desired. With smaller cases I use .2-.3 gr increments initially and then use .1 or .2 gr to weak. The .22H and 25-20 size cases require the .1 gr and the .222 size case up through .222 Rem Magnum get .2 gr tweaking.

This applies to cast as well as jacketed bullets.

I most often through powder charges as the #55 will throw charges +/- .1 gr with many powders. For my long range accuracy loads (varmint and match) I weigh the charge to the .1 gr. That might not be any better (so far my velocity and pressure testing show it isn't) than a thrown +/- .2 gr but it sure makes me feel better knowing for absolute sure the charge is exact when shooting a match or trying for that 800+ yard rockchuck.

Larry Gibson

[S.R.Custom]

None of the BR guys worry about it either and most never weigh a charge...

When it comes to handguns and cast bullet guns (AKA lever guns), no, I don't sweat anything much smaller than +/- 0.5 grs when working up a load. But when I've worked up a load that works, I try to hit the recipe by +/- 0.2 grs if the equipment I'm using can do it without trickling.

My precision rifles are another story. I'll work up a load for accuracy as tight as I can get, assuming a measurable, repeatable performance. In the case of .308s and 7mm magnums, this usually means figuring out a load down to about 0.3 grs. Once the load recipe is determined, I will, however, trickle every subsequent "production" load to right at 0.0, or +/- nothing on the scale.

Why? Consistency. There are enough other variables I have little or no control over (temperature, bullet to bullet variances, primer inconsistencies, etc.) that I don't need to exacerbate any variation by being sloppy with the scale. In other words, if I get a flyer in an otherwise tight group, I know for a certainty it wasn't because of a light powder charge.

As for stool shooters saying they don't use a scale, don't you believe it! These shooters are not only the most incrementally obsessive guys I've ever known, but they are not above lying if they think it will get them an advantage... As for not using a scale on the line, that's often true. But for a reason that's not readily apparent to the casual observer-- the damned things are useless in the wind.