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Discussion Starter · #1 · (Edited)
I'm wondering if we really know that a rifle is load/velocity sensitive. We've all heard that all rifles have different preferences for loads/velocities, etc. Yet, I recently read an article about "universal" loads where they actually identified some loads, actually if I recall correctly, factory loads, that shot about the same in every rifle they tested.

Then, I had an interesting experience. I was shooting incremental charges to identify the best group and something very interesting happened. One charge, 22.3 gr, with Sierra 77 gr MK bullets gave the following results.

5/15/2021 - 0.344 MOA
5/16/2021 - 0.287 MOA
5/17/2021 - 0.315 MOA
5/19/2021 - 0.315 MOA

On four separate days, I had four groups from the same charge produce four three shot groups no bigger than 0.344 MOA! What more could one ask for! Unfortunately, the story doesn't end there.

So I focused only on the 22.3 gr charge and loaded up a bunch of rounds. I would shoot these as 3-shot groups. This is where things took a surprising turn. The first group was,

0.478 MOA

No surprise here, we pretty well know that 0.3nn groups were going to spread some, so 0.478 is not a surprise.

The next 12 groups were mind boggling - what is going on! How do we get from four days in a row of 0.344 MOA max to a group over 1 MOA??? And, as you can see, interspersed among all the groups are a couple of 0.3nn groups. Very strange.

0.869
0.783
0.879
0.840
0.716
0.382
1.051
0.669
0.802
0.907
0.334
0.879

As I thought about this, it occurred to me, how easy it would have been to stop at the four amazing groups and declare that the best charge. However, when I plotted all the charges, here's what I got,



That charge that started out so amazing, turned out to be the worst of all the charges!

Of course, I had many more groups with the 23.5 gr charge than all the others. That prompted the thought if I had shot the same number of groups with the other 6 charges, would they spread out too? And there's the question!

If we were to shoot a large number of groups with every charge would the group sizes sort of even up or would one charge show up as a distinct best performer?

So, guess what we're going to do! You guessed it - we're going to shoot a bunch of groups at each charge and see what happens!

What I'm looking at right now is shooting 20 3-shot groups for 7 charges. I'd like to do 30 groups but that's just a bit much. 20 3-shot groups for 7 charges would be 20 x 3 x 7 = 420 rounds!

This will take a while, about 20 days (one set per day). Then there will be days I can't make it to the range so this could wind up running into 25-30 days.

That's a lot and it's going to take a lot of determination on my part to stick with this. So what's the reward? There are only two outcomes. One, the charges will all shoot about the same, or two, one (or two) charges will produce a significantly tighter group(s) and hand in hand with that is that some charges may produce significantly larger groups.

The overall end result will demonstrate if rifles do prefer one load or not.

First set (1 of 20):



2nd set (2 of 20):
This should get interesting!


3rd set (3 of 20):
Wow - look at the 21.5 and 22.1 gr charges! But, I've seen that before only to watch the group size grow and grow. As Yogi says, "It ain't over till it's over." 馃槉

The groups for the 21.5 gr charge are right on top of each other, but the 22.1 charge has slightly tighter groups.



4th set (4 of 20):
That 21.5 gr and 22.1 gr groups are hanging right in there!



They're hard to see, so here's a blow-up of the 21.5 - 22.1 charges. You can barely see the four group symbols they are so tight!

356987


5th set (5 of 20):
I don't know if there's a limit on how many pics can be posted in one post, so in order to minimize post counts, from this point forward, I'll make the pics larger in hopes that will eliminate the need for additional zoomed in pics like the one above.

BTW, if there's any doubt how many dots you should see per charge, you can look to the legend at the right and count the dates. That's how many dots you should see per charge.

So far, the pattern continues...


6th set (6 of 20):
This chart is a bit different. Because of the number of groups, things were starting to get cluttered. So in an attempt to help with that, I changed the vertical axis from 0.0 - 1.7 MOA to 0.1 to 1.4 MOA. That helps to spread things out a bit.

I also added blue bars representing the average group size for each charge. The bars are hard to see in some of the groups.



With 6 sets in, a trend is developing. I'll likely do two more sets tomorrow and two more sets the next day which will bring the set count to 10. If I don't see a significant change, I'll likely stop at 10 sets.

7th & 8th sets (8 of 20):
Quite a few things going on here. I have now dropped both the 23.0 gr and 23.3 gr charges because they were so diverse I could not shoot enough to make the group spread any smaller. Hence, it would be a waste of time and resources to continue shooting those two charges. The same is also true of the 22.4 gr charge, but it was a lot easier to drop the 23.0 & 23.3 charges from the chart than it would be to drop the 22.4 charge, so I just left it.

You can see the chart now only shows the lower 5 charges.

In post #21 I posted that I was not going to count set 7 as shot because I had to shoot it on a different range. However, when I shot the next set on my regular range, I could see no rationale to drop or re-shoot set 7, so it counts after all.

Another thing about this chart is that 22.7 gr charge. If it were not for that one group shot on 6/8/2021, that charge would certainly be a contender. I tried dropping the high and low groups for the 22.1 gr and 22.7 gr charges to see how that looked - I was surprised to see it looked worse than not dropping them. Still that 22.7 gr isn't that bad. That one group is well under 1 MOA and the rest are under 0.65 MOA!

While the trend remains pretty much unchanged, there is a slight change in charge 22.1 gr. It is growing but by tiny amounts. That is not surprising. I now have 24 shots per charge and the more one shoots, the larger the group is going to get until we reach a group size that all shots will fall in. I don't know what that is for the 22.1 gr charge, but since 30 is considered an adequate sample size, I'm not far from that at 24 shots. Two more sets will put me at that statistical threshold. So whatever the 30 shot group is, I'm gonna call that good! More about that when I'm finished.

When I started this I was thinking about 20 - 30 3-shot groups. But when I realized, altogether I'm approaching 30 shots per charge, the aggregate effect is 30 shots of one charge. That's enough!


Maybe only two more sets to go! 馃檪
 

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I really enjoy your logic and experiments, Tangle, and look forward to seeing how this turns out. As a shaky old shooter, it's important to me to know what possible with the gun versus what's possible with me.
 

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Are you clamping the gun down, or shooting off a bipod or bags?
The only thing that could throw the results off (assuming your cases are all identical, charges are accurate, and dies are set up properly) is the human factor.
 

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Discussion Starter · #4 ·
Are you clamping the gun down, or shooting off a bipod or bags?
The only thing that could throw the results off (assuming your cases are all identical, charges are accurate, and dies are set up properly) is the human factor.
What I want to test is the normal load development methods. These generally consist of shooting a supported gun rather than a clamped gun.

Even considering the human factor, the human factor will be present in all loads so there should be a leveling out due to the averaging effect of shooting so many rounds per charge. It is unlikely that the human factor would have a more significant effect on one charge than all the others.
 

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I'm wondering if we really know that a rifle is load/velocity sensitive. We've all heard that all rifles have different preferences for loads/velocities, etc. Yet, I recently read an article about "universal" loads where they actually identified some loads, actually if I recall correctly, factory loads, that shot about the same in every rifle they tested.

Then, I had an interesting experience. I was shooting incremental charges to identify the best group and something very interesting happened. One charge, 22.3 gr, with Sierra 77 gr MK bullets gave the following results.

5/15/2021 - 0.344 MOA
5/16/2021 - 0.287 MOA
5/17/2021 - 0.315 MOA
5/19/2021 - 0.315 MOA

On four separate days, I had four groups from the same charge produce four three shot groups no bigger than 0.344 MOA! What more could one ask for! Unfortunately, the story doesn't end there.

So I focused only on the 22.3 gr charge and loaded up a bunch of rounds. I would shoot these as 3-shot groups. This is where things took a surprising turn. The first group was,

0.478 MOA

No surprise here, we pretty well know that 0.3nn groups were going to spread some, so 0.478 is not a surprise.

The next 12 groups were mind boggling - what is going on! How do we get from four days in a row of 0.344 MOA max to a group over 1 MOA??? And, as you can see, interspersed among all the groups are a couple of 0.3nn groups. Very strange.

0.869
0.783
0.879
0.840
0.716
0.382
1.051
0.669
0.802
0.907
0.334
0.879

As I thought about this, it occurred to me, how easy it would have been to stop at the four amazing groups and declare that the best charge. However, when I plotted all the charges, here's what I got,



That charge that started out so amazing, turned out to be the worst of all the charges!

Of course, I had many more groups with the 23.5 gr charge than all the others. That prompted the thought if I had shot the same number of groups with the other 6 charges, would they spread out too? And there's the question!

If we were to shoot a large number of groups with every charge would the group sizes sort of even up or would one charge show up as a distinct best performer?

So, guess what we're going to do! You guessed it - we're going to shoot a bunch of groups at each charge and see what happens!

What I'm looking at right now is shooting 20 3-shot groups for 7 charges. I'd like to do 30 groups but that's just a bit much. 20 3-shot groups for 7 charges would be 20 x 3 x 7 = 420 rounds!

This will take a while, about 20 days (one set per day). Then there will be days I can't make it to the range so this could wind up running into 25-30 days.

That's a lot and it's going to take a lot of determination on my part to stick with this. So what's the reward? There are only two outcomes. One, the charges will all shoot about the same, or two, one (or two) charges will produce a significantly tighter group(s) and hand in hand with that is that some charges may produce significantly larger groups.

The overall end result will demonstrate if rifles do prefer one load or not.

The first set of 20


Only 19 to go 馃槦
Be sure to record the humidity on each day. I saw something a while back about humidity having a greater effect on burn rate than most people have thought.

Might have to start storing precision ammo in air-tight containers with desiccant.
 

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Discussion Starter · #6 · (Edited)
Be sure to record the humidity on each day. I saw something a while back about humidity having a greater effect on burn rate than most people have thought.

Might have to start storing precision ammo in air-tight containers with desiccant.
You wouldn't happen to remember where you saw that?

I ran 1% to 99% humidity on my ballistics calculator and got a 0.01MOA difference at 300 yards. Strelok Pro gave a bit more at 0.03 MOA.

However, that is a good thing to keep in mind. I'll be shooting at 50 yards to minimize all kinds of things, wind effect being the biggest concern.

Thanks for the suggestion!
 

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You wouldn't happen to remember where you saw that?

I ran 1% to 99% humidity on my ballistics calculator and got a 0.01MOA difference at 300 yards. Strelok Pro gave a bit more at 0.03 MOA.

However, that is a good thing to keep in mind. I'll be shooting at 50 yards to minimize all kinds of things, wind effect being the biggest concern.

Thanks for the suggestion!
Found it!

 

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Discussion Starter · #8 ·
Found it!
Many thanks!!!

I'm gonna have to load and take advantage of a weather break, but I did watch enough to know I want to watch more! I watched just enough to hear, "...at long ranges..." - can't wait to see/hear the rest!

I do record temps and now I'm going to start recording humidity. It's hardly anymore trouble to read and record both since my Kestrel displays both.
 

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Many thanks!!!

I'm gonna have to load and take advantage of a weather break, but I did watch enough to know I want to watch more! I watched just enough to hear, "...at long ranges..." - can't wait to see/hear the rest!

I do record temps and now I'm going to start recording humidity. It's hardly anymore trouble to read and record both since my Kestrel displays both.
It's very interesting the wide velocity change he experienced with equal weights of powder, just different moisture content due to humidity. Would equal volumes of powder produce more consistent velocities? Would a good powder thrower produce better results than weighing charges? Do we need to store powder and ammo in a humidity controlled container to get consistent ammo? An interesting vlog.
 

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I always want to watch The Addams Family after seeing this guy.

My house stays 55-60% humidity about year round. My powder should be stable.
 

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Discussion Starter · #11 ·
Hmmm, hmmm, hmmm - as in thinking about all this.

What's bothering me is, in his tests he chrono'd 9 shot groups and found a velocity variation of 220 fps.

I recently chrono'd 52 rounds of the very same charge, bullet, etc. over a 7 day period and I only got a velocity variation of 87 fps with an SD of 15.3 fps for the entire 52 rounds.

I always leave a small amount of powder in my power hopper and never return it to the canister unless I'm changing powders.

It could be that my humidity is far more tightly controlled than those he used in the test. I can't help but wonder if the reason we haven't heard about this from precision shooters, is because it really isn't a problem. I would think it would be extremely rare that we would have powder exposed to the humidity extremes he used. OTOH, humidity could account for some of the velocity variations we see.

IF humidity is significant, I'm not sure if there's a good way to control it. For example, each time we open a container of powder, we expose it to ambient humidity. My PRS buddy always returns his powder to a closed container, but in doing so, he is mixing powder that has been exposed to ambient humidity for as long as it takes him to complete a reload session. Now he has powder that was not exposed for as long (in the sealed container) mixed with a powder that was exposed to room humidity. That's probably not good either.

It's one thing to store/keep a powder in controlled conditions via sealed containers, etc., but it's quite another thing to get the protected powder into a number of cases without exposing the powder to uncontrolled conditions. Then what would we do with the left over powder from the loading session?

I saw an article that stated that the POI shifted about 0.5 MOA per 20% change in RH. However, they are talking about how the RH in the field affect external ballistics. Frankly, I don't believe that. If that were true, all 3 of the ballistics calculators I checked from 1% to 99% are bad wrong! They showed no more than a 0.03 MOA change in POI at 300 yards for the 1% - 99% RH variation.
 

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Hmmm, hmmm, hmmm - as in thinking about all this.

What's bothering me is, in his tests he chrono'd 9 shot groups and found a velocity variation of 220 fps.

I recently chrono'd 52 rounds of the very same charge, bullet, etc. over a 7 day period and I only got a velocity variation of 87 fps with an SD of 15.3 fps for the entire 52 rounds.

I always leave a small amount of powder in my power hopper and never return it to the canister unless I'm changing powders.

It could be that my humidity is far more tightly controlled than those he used in the test. I can't help but wonder if the reason we haven't heard about this from precision shooters, is because it really isn't a problem. I would think it would be extremely rare that we would have powder exposed to the humidity extremes he used. OTOH, humidity could account for some of the velocity variations we see.

IF humidity is significant, I'm not sure if there's a good way to control it. For example, each time we open a container of powder, we expose it to ambient humidity. My PRS buddy always returns his powder to a closed container, but in doing so, he is mixing powder that has been exposed to ambient humidity for as long as it takes him to complete a reload session. Now he has powder that wa
s not exposed for as long (in the sealed container) mixed with a powder that was exposed to room humidity. That's probably not good either.

It's one thing to store/keep a powder in controlled conditions via sealed containers, etc., but it's quite another thing to get the protected powder into a number of cases without exposing the powder to uncontrolled conditions. Then what would we do with the left over powder from the loading session?

I saw an article that stated that the POI shifted about 0.5 MOA per 20% change in RH. However, they are talking about how the RH in the field affect external ballistics. Frankly, I don't believe that. If that were true, all 3 of the ballistics calculators I checked from 1% to 99% are bad wrong! They showed no more than a 0.03 MOA change in POI at 300 yards for the 1% - 99% RH variation.
One of the things not addressed is how rapidly the powder absorbs moisture in the air. Take, for instance, one hour, the effect may be minimal or the powder may have absorbed as much as it can. Nonetheless, I found it interesting because I hadn't really considered that the RH would affect the weight of the charge so much, nor had I considered that the moisture content of the powder would affect the velocity as much as it apparently does.
 

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Discussion Starter · #13 ·
I'm not so sure. I watched this video some time back,
It's a long video but Vortex Nation hosted some top ranked F-class shooters to learn what is involved to be successful in F-class shooting. They talked about literally splitting a kernel of powder, not a grain, but a kernel, to get the precise charge WEIGHT. Throughout the video they talk about the tricks of the trade, setups, techniques, etc., but not once do they say anything about maintaining the humidity the powder, nor do they say anything about loading by volume rather than weight. In fact early on in the video, about the 20 minute mark, the F-class guy says that hits are determined by about 30% at the reloading bench and the rest is environment assessment and making better decisions.

So, if only 30% is determined at the reloading bench and they split kernels to get a precise weight then there is no way humidity is having the effect on velocity that is discussed in the video about humidity. Of course it is possible that they maintain a very carefully controlled environment for their powder during the loading process but failed to mention that. So that's possible, but not very likely.
 

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Discussion Starter · #14 ·
Just in case you missed it, set 3 is now up in the OP.
 

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Discussion Starter · #15 ·
I had to take a target pic to send to a buddy, so I thought I might as well post it. This is this morning's set. Shot at 50 yards to eliminate as many external influences as I could.

 

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Discussion Starter · #16 ·
Just a heads up, set 4 now up in the OP and, here's a bonus - for free!

This is a technique test to see if I move the gun in the process of pulling the trigger. Here's how the drill works. I shot this using a bipod and small rear bag. I first shot three shots as normal as a baseline or reference. Then the test: I sight in, close both eyes, and fire a shot. I repeat this two more times.

Here's the result - I don't move the gun when I pull the trigger! POA for the baseline shots was the upper corner of the "A" - of course the "A" would have to be oriented sideways 馃ゴ The POA for the "blind" shots was the lower corner of the "A".

 

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Discussion Starter · #18 ·
Set 6 is now up in OP.

I'm noticing some pressure now, especially on those really tight groups. All it would take is one "oops" on my part to ruin a group. I'd likely discard the group and reshoot it, but WOW, that's a lot of trouble.
 

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Discussion Starter · #19 ·
I forgot - before the 6th set, I cleaned the barrel. It had 126 rounds through it and I really think it would have been fine without cleaning but if I hadn't cleaned it, and the groups started to spread, I would have to dump the set, clean the barrel, and reshoot the set. So cleaning the barrel seemed like the best approach.

I only did a carbon clean, i.e. did NOT do a copper clean. After cleaning, I shot 9 fouling rounds to condition the barrel before I started shooting groups.
 

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Apparently that setup is not fond of the higher charges.
 
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