Loading by volume vs weight

[abunaitoo]

So sitting here thinking (most times not a good thing) about reloading.
I've noticed that with stick and flake powder, there is variations in size.
Slight variation, but still it's there.
Being that it's not uniform, it would seem the charge would not be consistent.
If going by weight, you'd get a different amount or granules because of the different sizes.
If going by volume, you,d again get different amounts of granules because of the different sizes.
Friend of mines shoots a good rifle and we can't figure out why the groups vary with the same charge.
Digital scale, same lot shells and heads, same lot of primers.
Everything as much the same as he can get it to.
His is a compressed load.
I keep on telling him it the "IPT" that's the problem.
After looking at some powders, maybe not.
Any comments???
Maybe I'm just thinking bubbles.

[Bazoo]

Perhaps the powder don't like being compressed and is at the edge of it's optimum pressure spectrum.

Or perhaps the load is right on the edge of a good spot for barrel harmonics.

Or maybe the brass needs annealing and is causing differences in neck tension.

Or if he's neck sizing only, try full length sizing and see if it goes away. In the Lyman 47 I think, there is an article on accuracy and the gent describes being at the range with a known good bench shooter. His rifle was acting up and he couldn't figure out why. So it dawned on him that maybe the cases needed FL sizing. Upon FL sizing the rifle started acting as normal. It didn't theorize as to why, but I'd guess maybe differentiating stress on the action affecting harmonics.

Maybe switch batches of brass. Check the new batch with water to make sure internal volume stays the same and you should be safe switching without working up again? I've never done this so I'm theorizing it to be correct so try at your own risk to shooter and rifle, but I'd try it personally.

[Tatume]

Size of the particles is not as important as average size of the particles. Each charge is a large number of particles, and the average number of particles will obey the "law of large numbers." It will be approximately the same from charge to charge.

[44MAG#1]

How much do the groups vary? Some variation is to be expected. Reason, nothing is perfect. We all want perfection in an imperfect world made up of imperfect humans.
There probably isnt any seasoned BR shooter that shoots the same exact size groups each time they shoot a group and they are the bunch jumping through hoops to get those teeny tiny groups with the hopes of winning a trophy.
Over thinking like some do just makes more work for a sport that is suppose to be fun. Unless the groups vary greatly dont worry about it. Remember nothing is perfect or close to it. Never will be as long as humans are involved in anything there is for them to be involved in. What about changes in lots of powder, lots of primers lots of bullet and cases? Variations in ambient temperature. Enough things to run an over thinker crazy.
Hope I didnt get out of line with my post. If I did let me know and I will delete it.

[trapper9260]

How much do the groups vary? Some variation is to be expected. Reason, nothing is perfect. We all want perfection in an imperfect world made up of imperfect humans.
There probably isnt any seasoned BR shooter that shoots the same exact size groups each time they shoot a group and they are the bunch jumping through hoops to get those teeny tiny groups with the hopes of winning a trophy.
Over thinking like some do just makes more work for a sport that is suppose to be fun. Unless the groups vary greatly dont worry about it. Remember nothing is perfect or close to it. Never will be as long as humans are involved in anything there is for them to be involved in. What about changes in lots of powder, lots of primers lots of bullet and cases? Variations in ambient temperature. Enough things to run an over thinker crazy.
Hope I didnt get out of line with my post. If I did let me know and I will delete it.

You sum it up the best

[Hickory]

When I was shooting informal benchrest matches, I once forgot to take my power measure with me.
I had a Lee powder scoop that was close to the weight powder in my regular load. Using that to load my ammo, I still placed 3rd in a field of 38 other shooters.
There are a lot of other factors more important than exact powder weight that makes an accurate load.

[40-82 hiker]

Friend of mines shoots a good rifle and we can't figure out why the groups vary with the same charge.


I try to remember that on top of ALL variables, we deal with circular error on every shot of every group. Even if our stated goals of minimizing variables in our loads are carried out, every group we fire has a different accumulation of circular error, making our groups larger or smaller, even with no other influence. To understand where our loads are from the standpoint of accuracy, we need to track the average size of all groups, from small to large, with a given load and loading practices. I just cannot do that. The measuring, the documenting... Whew! I used to do that when I shot NM many years ago. Too much for now, though.

So, now throw in the vagaries of barrel harmonics, trigger technique, heartbeat, temperature, humidity, bedding, charge variances, boolit variances, oh heck, the list is endless for vagaries over short and long time spans! Oh, not to mention being imperfect humans...

YMMV

[Froogal]

I have played around with black powder substitutes a little, hoping that I could use the Lee powder measure to charge each shell, but I learned that each dipper of powder will not weigh the same as the previous dipper, so I gave up on the powder measure and just use the dippers.

I wonder if the guys from back around 1880 or so, who reloaded ammo, had any kind of scale to use, or did they just use a dipper? Or did they just sort of guess?

[sundog]

A couple things come to mind. First, maybe that gun is not as good as y'all think it is, just sayin'. Next what Hickory said about charges.

One of the better reads on this subject is Secrets of the Houston Warehouse (https://precisionrifleblog.com/2013/10/18/secrets-of-the-houston-warehouse-lessons-in-extreme-rifle-accuracy/).

[kevin c]

That was a very interesting read, thanks!

[429421Cowboy]

A couple things come to mind. First, maybe that gun is not as good as y'all think it is, just sayin'. Next what Hickory said about charges.

One of the better reads on this subject is Secrets of the Houston Warehouse (https://precisionrifleblog.com/2013/10/18/secrets-of-the-houston-warehouse-lessons-in-extreme-rifle-accuracy/).

Thanks for that, some very good reading!

[Mr_Sheesh]

If the stock is almost touching the barrel when he holds it one way, and does touch when he holds it a little differently, that will definitely change point of impact. Friend had to learn to not twist the forearm of one rifle as it'd touch the barrel if he torqued it and he was getting horizontal stringing; I had a nice Rem 700 which had its' factory (wood) stock warp over time, suddenly one year it started horizontally stringing. Stocks can warp vertically too, I imagine. Consistent bedding or free floating the barrel should solve that, though.

[Winger Ed.]

He may have more going on than a issue with the powder & charge weight that the rifle 'just doesn't like'.

Among all the other things that can effect groups-
Another possibility is he isn't as good of a marksman as he thinks.

Have you fired it yourself to compare?
I've seen groups shrink dramatically by changing the shooter.:bigsmyl2:

[abunaitoo]

The rifle shoots less than 1/2" groups at 100.
Sometime all touching.
It's the one fliers in some strings he's chasing after.
Consistency
He shoots a group of five.
Lets it rest to cool the barrel.
Then shoots the next five.
And on and on.
No cleaning in between.
No pattern as to which string will open up.
I keep on telling him it the "IPT"
I'd be more than satisfied with what it shoots.
I guess he's chasing perfection.

[Winger Ed.]

I guess he's chasing perfection.

Yeah. Most of us do that.
If it was easy, we'd all have achieved it.

[Bazoo]

I've been thinking on it. I betcha it's a scope or mount problem.

[megasupermagnum]

I found that once you get to less than 1/2" accuracy levels, anything can have an effect. I had a rifle that I had to have the stock screw tightened just right to have it shoot that well. I guess that's why the best shooters never take the stock off.

I personally can't stand such finickiness.

[samari46]

Benchrest shooters once they have dialed in the most accurate load usually use a powder measure and they change the amount of powder by varying the amount of clicks either up or down according the changing conditions. Weather, humidity,temps and so on. Powder measures like Harrels (spelling) I used to see at our local home range. And benchrest shooters have been known to be pushing the limits when striving for the best accuracy. Our club used to host the Crawfish Invitational every year. Folks would come from all over to participate. Frank

[Silvercreek Farmer]

How do they look over the chrono? If the extreme spread is low, I'd look somewhere else.

[Thin Man]

It has been too long since I read the following summary I am going to try to describe, so please tolerate me on this. An older article spoke about a known and respected shooter who was working to create tighter groups. He would drop his powder into a scale pan, then use a trickler to bring the charge weight up to his specific and exact charge weight. Another shooter claimed "just drop your charges and they will work out better for." "Yeah, right, sure" thought the shooter, but he tried this routine and suddenly his groups got smaller. Thinking all this was a fluke he repeated the test. His first rounds carried weighed charges and the next group carried dropped (but not weight balanced) charges. Guess what - the dropped charges again gave a tighter group. The shooter was genuinely impressed with the results. Now I will work on trying to locate that article to share the origin, names of people involved, etc. This was an eye-opened when I read it.

[sundog]

What is the load data?

What is the case prep?

[johnho]

When I make bread I do everything by weight. Volume means nothing and can cause problems if you don't have the right weight of the ingredients.

[abunaitoo]

Case prep.
Deprime and neck size I forget what brand dies.
Vibrate clean in corn cob.
Clean primer pocket.
Measures OAL. Trim as needed.

I forget what the load was.

He weighs each charge. Digital scale.

He has one of those strap on the barrel cronies.
Spread is very low.

[megasupermagnum]

Case prep.
Deprime and neck size I forget what brand dies.
Vibrate clean in corn cob.
Clean primer pocket.
Measures OAL. Trim as needed.

I forget what the load was.

He weighs each charge. Digital scale.

He has one of those strap on the barrel cronies.
Spread is very low.

The digital scale is a red flag to me. Unless you are intimately familiar with your own unit, they are inaccurate. The readings drift as they warm up, and are more difficult to use do to reading hold features. Try a good beam scale.

But if velocity spreads are low, say sub 30 fps ES, then that's not the problem.

[perotter]

Something to remember when using weight is the changes caused by moister percent and the percent of 'solvent' in the powder. There was an article written on this about 20 years ago about the testing of this. Likely there will be more variation in 8 pounder use up over 8 years than a 1 pounder used in a year. I load by volume, not weight.