How much difference does. 04g make in accuracy? (Corrected)

[urbanrifleman]

I have nodes in 6bra and 6xc that shoot in the same hole that are at least .3 grains wide.... if not more.

And, of course, this all relative. If you are shooting a say, a 33xc with Retumbo .4 grains would be tiny at 100 grains of powder verses a 223 with 23 grains of powder...

 

[7br]

Not an F-Class or PRS shooter. Mostly groundhogs and an occasional local SBR match. My personal parameters are +/- .05gr for a .1 spread. 6br, .223 Wylde and .204 Ruger with extruded powders at 100yds delivers consistent 5 shot ragged holes easily covered with a dime.

 

[Pete Wass]

Sorry I lead many of you astray. I was looking for information on hundredths. Ill correct the headline.

 

[searcher]

I'm not knocking the anal folks who must measure to the nth decimal place, as I'm kind of in that category - but when i think back on all the

Just an observation here. I read the posters who scoff at a .04 variation in powder wt. as not making a difference in overall accuracy. Among this same group, they will post how a .005” difference in seating depth was a game changer for their group size. Guess it depends on the shooting discipline ur are competing in!
The powder u are using will often dictate the fidelity of ur powder charge. Each kernel of stick powder will have a different value depending on the powder itself. A kernel of Varget is typically .02 grain, powders like VV140 cut that down to .015 gr. With that difference, ur loading window can now become smaller. At long range where ur taking quality control checks to the extreme ( weighing primers etc.) that smaller powder charge window can matter ( low es & sd).

I mentioned a .004 variation not being much at all - not .04. Having a .004 variation in powder will result in a few feet per second in most calibers, perhaps less in the largest ones. A .005" seating depth variation is HUGE for most tuned rifle loads, often turning a great load into a poor one. Granted, if one is shooting a pistol at a target from 75 feet, one might not see much if the seating is .005" off. I know this from having shot 3-gun bullseye matches for years. But I also know from shooting bench rest for many years, that .005 depth can be like the Grand Canyon. If I were shooting against a peer and both of us were challenged to change to either a .004 powder deviation or a .005" change in depth (in either direction) with all else being the same, I'd jump on the .004 all day long. I know the .005" seating depth change is going to change my velocity one way or the other FAR more than a .004 change in powder - whether stick, ball or whatever. If shooting a rifle, these same facts will apply whether shooting PRS, benchrest or any other discipline. Perhaps we disagree on this....

 

[searcher]

Depending on the tune and the rifle/load...you won't see that.

I agree. 4/10 of a grain will completely change the load in my .17 Hornet. In my .375 H&H, not noticeable at all.

 

[Bob3700]

I'm not knocking the anal folks who must measure to the nth decimal place, as I'm kind of in that category - but when i think back on all the

I mentioned a .004 variation not being much at all - not .04. Having a .004 variation in powder will result in a few feet per second in most calibers, perhaps less in the largest ones. A .005" seating depth variation is HUGE for most tuned rifle loads, often turning a great load into a poor one. Granted, if one is shooting a pistol at a target from 75 feet, one might not see much if the seating is .005" off. I know this from having shot 3-gun bullseye matches for years. But I also know from shooting bench rest for many years, that .005 depth can be like the Grand Canyon. If I were shooting against a peer and both of us were challenged to change to either a .004 powder deviation or a .005" change in depth (in either direction) with all else being the same, I'd jump on the .004 all day long. I know the .005" seating depth change is going to change my velocity one way or the other FAR more than a .004 change in powder - whether stick, ball or whatever. If shooting a rifle, these same facts will apply whether shooting PRS, benchrest or any other discipline. Perhaps we disagree on this....

So I assume that you are chasing the throat in your bbl as the round count climbs to maintain the<.005" variation in seating depth?
If you shoot a discipline where you can seat your bullets long and let the bbl determine the actual depth, then a variation in seating depth of .005" in a loaded round is inconsequential. A variation of .04gr. of powder at 1K may give you just enough vertical to cause issues.
Short range benchrest may be one of the games where that .005" matters. Our experiences may just differ on this one.

 

[DShortt]

I agree. 4/10 of a grain will completely change the load in my .17 Hornet. In my .375 H&H, not noticeable at all.

So.... let's review definitions here.

.4 = 4/10

.04 = 4/100

.004 = 4/1000

I don't think I'm off in the weeds. (?)

And we are talking about divisions of a grain to begin with.....

The OP listed .4 in the thread title, yet .004 in his verbiage. Then began talking about .02.

WTH?

 

[Dufas]

0.4gr @ 100, yup. 0.04 gr @ 100 nope.

 

[hoz53]

So.... let's review definitions here.

.4 = 4/10

.04 = 4/100

.004 = 4/1000

I don't think I'm off in the weeds. (?)

And we are talking about divisions of a grain to begin with.....

The OP listed .4 in the thread title, yet .004 in his verbiage. Then began talking about .02.

WTH?

he did apologize in #43 and said he made a typo and was looking for info in hundredths which would be .04

 

[hoz53]

0.4gr @ 100, yup. 0.04 gr @ 100 nope.

.04 gr @ 1000 yup

 

[DShortt]

he did apologize in #43 and said he made a typo and was looking for info in hundredths which would be .04

OK, well I'm gonna call myself out as a Neanderthal then.

I'll never fret over .00

 

[Larry Koch]

I'd worry about the wind.

 

[DShortt]

I'd worry about the wind.

Bingo!

 

[searcher]

So I assume that you are chasing the throat in your bbl as the round count climbs to maintain the<.005" variation in seating depth?
If you shoot a discipline where you can seat your bullets long and let the bbl determine the actual depth, then a variation in seating depth of .005" in a loaded round is inconsequential. A variation of .04gr. of powder at 1K may give you just enough vertical to cause issues.
Short range benchrest may be one of the games where that .005" matters. Our experiences may just differ on this one.

No - I don't chase the lands in any of my rifles. Some of the barrels on my varmint rifles have well over 6,000 rounds on them and I found better success in re-tuning the load as the barrel wears, rather than chasing lands. When that no longer works, I replace the barrel. Mind you, these are all barrels where I'm shooting off the lands.

What you say here about chasing the lands to maintain under .005" seating deviation if fine if you want a jammed load. But not all loads are jammed and that .005" seating depth variation will bite you. But, maybe you have just never noticed the results by firing thousands of groups on paper?

As you state, it does depend on the discipline. I don't much shoot what some might call long range, has always been point blank bench rest, F-Class (600 yd.) and varmints. What you now post about seating depth, using the "soft-seat" method of allowing the bullet to push back into the case is NOT the same as having .005" variation as you earlier referred to. Doing the "soft seat" method, there is no (or very little) variation - as you know. That said, continuing to use that method over the life of a barrel, due to throat erosion, one has to periodically tweak the load anyway, as when the throat grows, one gradually loses velocity as the bullet is systematically further out of the case over time.

I employ the "soft seat" method on my target rifles with most loads and I know when the barrel is ready for replacement when tune can no longer be achieved. We all do things differently. But - ask any successful benchrest shooter if they would be O.K. with having .005" deviation in seating depth on their loaded ammo. See what they have to say. Then ask them whether .004 powder deviation would have stopped them from setting the world record they shot dumping powder straight from the hopper. And while far more guys are weighing now than 20 years ago, some of those records have yet to be broken. I'm not professing to tell you or anyone else what works - but I know from my own experience what will ruin a load for me - and what hasn't. I know in my small caliber rounds, just pushing the bullet in another .005" can result in a much bigger change in velocity than .004 grains of powder ever would. Not arguing with you here. Just not sure we are on the same page.

 

[Pete Wass]

I'd bet your case weight and volume is varying more than .040"gn. Check it out.

That's a very good point, the case volume.

 

[Pete Wass]

Which cartridge? I.e., how many grains in the load?

I shoot Mostly 30 BR and around 34gn of the powder they like. Since I have owned my V4, I do trust it to read in hundredths. I have checked its repeatability many times with a test weight.

I only shoot Short Range Score. What I do want is to make the best ammo I can make. That is the one thing I have the opportunity to do, is to make as close to perfect ammo as I can make. Murphy and O'Brien are always lurking, as we all know.

I have been shooting short range Score since 1999. I have seen equipment advance a lot in that amount of time, also what folks will accept for results of things. It's a shame I made such a mess of the post. What I hope to find was if someone had done enough testing to determine how much difference .04gn of powder makes in groups size and consistency.

I have been very busy and not able to get back here until this morning.

I believe everything matters when it comes to ultimate accuracy. From what I have read here, the LD folks have spent the most time and effort to find perfection in just about everything. Short range testing had seemed to hit a wall, for a long time. My thinking has been, I have the time at 81 yoa to do whatever I need to do to give myself the best possible opportunity to do my best whenever I compete, understanding that perfection in loading is only one piece of the effort. I don't want to be in a position where I have to say "Good Enough" when I have the equipment to make things as near to perfect as I can make them.

Thanks everyone for participating.

Pete

 

[SKWERLZ]

Have any of you tested loads that were .004 gn off a desired load. It gets to this .02 gn zone when using a V4. ,02 gn below and .02 gn over could give .04 gn swing. I always want exact chosen load but how much difference is a potential . 04 gn swing going to make in 100 yd groups?

N570 kernels weigh more than .04 grains.
.02-.04 variation is nothing to me.

A happy load will often tolerate .4 grain swings or more.

The tiny cartridges could certainly have a smaller window but the common 77SmK/8208 223 load usually seems to have a fairly decent operational range as well in my experience.

 

[Oso]

Son--Hey dad, I need $10

Dad--$8? I can't believe you want $6....what in the world will you do with $4?

This is one of my favorite Dad games with my kids!!! I overhear them talking to their mom in subdued voice, because they think she’s more likely to agree. I loudly restate their question or statement but change key components. 3-4 rounds of this back & forth before and they figure out that its not my hearing but rather me intentionally screwing with them.

I understand fat figuring the decimal spot. It happens…

 

[JFrank]

I compete, understanding that perfection in loading is only one piece of the effort. I don't want to be in a position where I have to say "Good Enough" when I have the equipment to make things as near to perfect as I can make them.

I’ve broken down charge ladders into 1/10 gr ( 6 kernel) increments to define the node width and edges, mostly at 500 Y and beyond and what I find is in a 6 br size case the node can be about 3/10 wide meaning to my targets that a middle will not be affected by .04 ( or 2 kernels) ~ unless I’m right on the edge of migration so with this in mind I think that at short range it may be even less influential compared to the other variables of short range shooting.

 

[Steve Donlon]

N570 kernels weigh more than .04 grains.
.02-.04 variation is nothing to me.

A happy load will often tolerate .4 grain swings or more.

The tiny cartridges could certainly have a smaller window but the common 77SmK/8208 223 load usually seems to have a fairly decent operational range as well in my experience.

One kernel of IMR 4350 weighs .033333 at the lightest. My scale will notice one kernel. So if my scale says I'm .1 over, I can take one kernel out of the pan to make it right and if I'm under , I just need to add one kernel. This does not happen often though. With other powders, I don't get over or under charges of powder. That's all I know about it. With my Chargemaster 1500. It looks like IMR 4350 is not a precision powder for many.