Load development- where to go from here?

[Ganderite]

Ganderite...is there a relationship between barrel harmonics and velocity for a given rifle and bullet weight? In other words if I am noticing repeated accuracy nodes at a window of velocity range in a rifle with same weight bullets, that looking for that velocity window (with same weight bullets ) in the same rifle is probable or predictable for accuracy? EDIT, or is this thinking false and I am fluking it off or the rifle is an anomaly?

Pardon any ignorance of my part, just trying to follow along with the information presented.

Noted on your comments regarding ES and SD. As well, to note: I load for hunting and to produce the most accurate ammunition I can with the tools I have, the locations available, and the knowledge I am gaining. Ranges I am comfortable in the field is up to 300 "ish" depending on circumstance and the rifle I have in my hands at the time. Side project is to see how well I can apply what I am retaining for plus 300 accuracy. Don't have the location to test at longer distances...yet.

Regards all,

Ronr

EDIT. I need to acknowledge the photo posted. I tip my hat to that.

I started off working in a ballistics research lab in 1964. My boss eventually stopped me from assigning a reason to each thing I saw.

If something worked better than something else, I would say something like "Oh, that is because this twist is more appropriate." My boss would explain that to prove that theory (e.g. the twist was the important variable) we would have to run a test on 10 samples of each twist with several thousand rounds of ammo - and he was not going to do that.

So when you ask about why something happens, I have learned to think "I don't care why. All that matters is that I find out what works best."

There are those who need and want 100 yard good groups. Benchrest shooters and many hunters, for example, don't shoot beyond 100. All they have to do is find a load that reliably shoots well. Not a difficult thing to do.

For those who want a rifle that shoots well to 300, or 500 or 1000 (target rifle shooters regularly shoot to 1000) I have learned that the only way to find a load that shoots well at 300, or 500, etc. is to test at that distance. There are lots of us who learned the hard way that 1000 yards is special for a 308 and the load that works at 800 might be poor at 1000.

Let's keep it simple and assume that you are hunter in the West, or an Eastern hunter that sometimes hunts the power line cuts and you want a rifle that is accurate to 300.

There are many variables in accuracy. Rifle bedding, action screw tension, quality of chamber and barrel, parallax of the scope. But for load development discussion we have just powder charge & seating depth and the resulting ES and barrel harmonic.

ES you can measure and see and it is obvious that less is better.

But you can't see barrel harmonics and it tends to get ignored. You can't see it at 100 yards on the target, but by 300 it is probably already the biggest and most important variable and becomes more important at the longer distances.

If I test at 500, I shoot a series of loads in 0.3 gr increments at choose the load that got the best vertical size. I typically develop loads solely on the basis of group size at a longer distance and have no idea of the velocity or ES until after the project. Then I chrony the final load for the note in the log book.

A two foot bar of steel that is hit with a 50,000 psi impact whips like a snake. If the ammo is consistent and the bedding is good, the whipping is consistent and the bullet exits the muzzle at the same place of its arc. There are just 2 possibilities. The barrel is on the way up when the bullet exits or on the way down.

At longer range the former will shoot a good vertical and the latter will shoot a tall vertical.*

If you understand this - good. If you don't, it does not matter. At 300 find the load that shoots well. What you are doing is finding the barrel vibration node for that bullet. When you try 43.0 gr and 43.5 gr and discover that 43.5 is much better, the reason for improved accuracy is most likely due to barrel harmonics, and not a better ES, etc.

If you change bullet (same weight) or change powder the node will be a bit different because the impulse will be a bit different.

I see guys developing loads at 100 and then testing at longer range. My comment is stop wasting time and powder. If you want a 300 yard load, you have to test there.

*Ammo varies in velocity. Other things being equal, the slower rounds will print lower and the faster rounds will print higher.

But other things are not equal. The muzzle is whipping - one way or the other.

If the muzzle is moving up, the slower round will exit a bit later and will be aimed a little more "up", offsetting the slower round printing lower. And the faster bullet will exit sooner, and be aimed a little lower. The result is a smaller group than otherwise.

And if the muzzle is moving down when the bullets exit, the group will be made even worse.

This is why we test a variety of loads to find what gets the best results.

If you don't handload, try several different bullet weights or brands of ammo, etc. and find the one that shots better than the others. It is probably the load that suits your barrel harmonics.

Conversely, if you have to shoot a given ammo, try it in different rifles and find the rifle it works best in.

 

[Ganderite]

Mine would change...

sunny day 100-150 fps faster.
Cloudy ...slower.


The biggest thing I found....was I would shoot the exact same load 2 days apart I. Same conditions.

The ES and SD would go from 10&5 to 50&25???

So I am starting to learn that you have to watch what your groups are telling you, watch Chrono....then shoot at 500 yards(+).....that's where your going to see IF you got an accurate load.

I guess I had a similar experience. I have lots of Chrony brand units, because they gave them to me. I have shot 7 of them, but still have 3 or 4.

I discovered that if I tested on a cloudy day, results were excellent. On a blue sky, results were erratic. The sky screens may solve the problem, but I just wait for a cloudy day.

I live on a farm, and the ammo to be tested accumulated on a table by the back door. When it gets cloudy or overcast I step out into the back yard and do my testing.

If I could only test on Saturdays when I go to the range, this reliance on cloud cover would not be acceptable.

 

[Mystic Precision]

Here is a target to illustrate the point that Ganderite is making... Testing with my FTR competition rifle at 250yds in very light air. I am doing some R&D with some new bullets. Each letter illustrates an increase in powder charge of 0.2 gr.

The pattern shown is repeated in pretty much every rifle I have ever tested over the last 20yrs... yes, that includes small to boomers... short and long barrels.... all sorts of actions and rifles styles. The key is proper and repeatable rifle set up, ammo and optics.

Anyways, load "A" is not ideal... still a 0.65 MOA group but not what I am looking for... most will be thrilled to hammer this group at 250yds. For F class, we can do alot better.

next step "B" illustrates what it looks like when you are going into the desired node.. yep, alot of vertical.... and VERY little windage. I bet this also has very good ES and SD numbers. Ball park a 0.4MOA group. Lots of shooters will stop here because their Chronie is telling them low ES and SD's which should produce fantastic results as far as they want to go. I can confirm that Load B SUCKS royally at 1000yds. What looks to be under 1/2 MOA vertical becomes a tall undriveable load at 1k.

Next step is what I am after. Load "C" drives them into a nice symmetric cluster.. ballpark 1/2" for 0.2MOA or less... and yes, this load proved awesome at 1k.

Now we are coming OUT of the node with load "D". Some will be tempted by the 2 snuggled up and make excuses for the 1 high shot. velocity is a hair faster but that vertical out IS a vertical out. Like Load "B", you are into the part of the barrel vibration where shots will go high (or sometimes low). Some will call these "flyers" or a pulled shot... when in fact, it is the ammo being slightly out of tune with the barrel. This gets to be a real hair pulling experience if shooting over wide ranges of temps and your loads go in and out of phase.

Load "E" looks great but isn't... still around 1" which at 250yds, some will be very pleased about and the vertical in this test group is low. Pressures are starting to show up. Tuning would be quite inconsistent and multiple groups of this load would show random patterns with some flat, some tall, some tight with outs, some loose and big. Add more fuel from this point just makes the groups bigger and more irratic and pressure signs would definitely be visible... but you would also see a big jump in velocities which some shooters want.

This is the biggest reason why competition shooters have invested in very good milligram scales. It doesn't take alot of powder change to affect the tuning and if the scale and/or dispenser is only accurate to +/- 0.1 to 0.2gr, load "C" would just be lost in the noise of the powder charge error.



When your load is right, using proper rests, and you are shooting well, this is the type of Vertical you can tune your rifle for. Again 250yds with a slight pick up in R to L mirage... otherwise, wind is calm. I didn't bother to hold off for the pick up. The 2 loads are not much different in final weight.

There is a huge amount of videos, blogs, and posts wrt to loading over a chronograph at 100yds. You can work with a common combo where the tuning falls into a narrow band and it works. But when working with unknowns or various chambers and bullets, the method here works reliably and repeatably and the tuning holds all the way out to whenever the bullet falls apart.

YMMV.

Jerry

 

[350 Mag]

I also meticulous weigh charges....but I just have a 5-0-5....

 

[Mystic Precision]

I also meticulous weigh charges....but I just have a 5-0-5....

If possible, test your scale to a quality milligram digi scale like a AND FX120I or Santorious or similar lab quality scale. Although the scale may read XYZ, you need to prove the mass that is actually in the pan. Do a sample size of 20 to 50 charges to confirm a trend.

If the scale proves to be reliable to the 0.1gr, AWESOME and treasure it.... if not, look for a remedy.

Of course, precise charge weights is just one part in a list of steps needed to make match grade ammo... but it is, to me, the most important step.

Jerry

 

[RonR]

Thanks Ganderite for the response. Lots here. I've keyed on a few things.

Let's keep it simple and assume that you are hunter in the West, or an Eastern hunter that sometimes hunts the power line cuts and you want a rifle that is accurate to 300.

Yes that's us. Learning more and applying to better handloads.

But you can't see barrel harmonics and it tends to get ignored. You can't see it at 100 yards on the target, but by 300 it is probably already the biggest and most important variable and becomes more important at the longer distances.

If I test at 500, I shoot a series of loads in 0.3 gr increments at choose the load that got the best vertical size. I typically develop loads solely on the basis of group size at a longer distance and have no idea of the velocity or ES until after the project. Then I chrony the final load for the note in the log book.

That's what's done here. Plug in the velocity numbers for calculators. Some may ask why bother if I am only shooting to 300 anyways, but I want to predict/anticipate know bullet location at longer distances. Maybe not for the field but for the range.

A two foot bar of steel that is hit with a 50,000 psi impact whips like a snake. If the ammo is consistent and the bedding is good, the whipping is consistent and the bullet exits the muzzle at the same place of its arc. There are just 2 possibilities. The barrel is on the way up when the bullet exits or on the way down.

At longer range the former will shoot a good vertical and the latter will shoot a tall vertical.

If you understand this - good.

Yes understood.

If you don't, it does not matter. At 300 find the load that shoots well. What you are doing is finding the barrel vibration node for that bullet. When you try 43.0 gr and 43.5 gr and discover that 43.5 is much better, the reason for improved accuracy is most likely due to barrel harmonics, and not a better ES, etc.

If you change bullet (same weight) or change powder the node will be a bit different because the impulse will be a bit different.

I think I understand but I will share why I asked. Results here from different handload combinations are indicating that within a velocity range the results are better groups. 100 or 200 yds doesn't matter. (Noted I haven't tested out to longer distances, and without experiencing barrel harmonic differences at longer distances relating to accuracy results.) Was just wondering if barrel harmonic relationships are tied to velocity. If I am picking up what you are putting down, a correlation between harmonics and velocity isn't something to bank on for predicting an accurate group. For example it seems in my 7-08, using 140 grain bullets, that velocities around 2730 plus minus 10 fps seem to group well, regardless of bullet choice/powder/primer combination.

I see guys developing loads at 100 and then testing at longer range. My comment is stop wasting time and powder. If you want a 300 yard load, you have to test there.

Agreed. Using a derivative of OCW and Jerry's publications to 200 and infrequently out to 300.

If the muzzle is moving up, the slower round will exit a bit later and will be aimed a little more "up", offsetting the slower round printing lower. And the faster bullet will exit sooner, and be aimed a little lower. The result is a smaller group than otherwise.

And if the muzzle is moving down when the bullets exit, the group will be made even worse.

Again thanks for the response. I learn and try to apply quite a bit of what you share.

Best Regards
Ron

 

[RonR]

View attachment 222015

next step "B" illustrates what it looks like when you are going into the desired node.. yep, alot of vertical.... and VERY little windage. I bet this also has very good ES and SD numbers. Ball park a 0.4MOA group. Lots of shooters will stop here because their Chronie is telling them low ES and SD's which should produce fantastic results as far as they want to go. I can confirm that Load B SUCKS royally at 1000yds. What looks to be under 1/2 MOA vertical becomes a tall undriveable load at 1k.

Next step is what I am after. Load "C" drives them into a nice symmetric cluster.. ballpark 1/2" for 0.2MOA or less... and yes, this load proved awesome at 1k.

Now we are coming OUT of the node with load "D". Some will be tempted by the 2 snuggled up and make excuses for the 1 high shot. velocity is a hair faster but that vertical out IS a vertical out. Like Load "B", you are into the part of the barrel vibration where shots will go high (or sometimes low). Some will call these "flyers" or a pulled shot... when in fact, it is the ammo being slightly out of tune with the barrel. This gets to be a real hair pulling experience if shooting over wide ranges of temps and your loads go in and out of phase.

Load "E" looks great but isn't... still around 1" which at 250yds, some will be very pleased about and the vertical in this test group is low. Pressures are starting to show up. Tuning would be quite inconsistent and multiple groups of this load would show random patterns with some flat, some tall, some tight with outs, some loose and big. Add more fuel from this point just makes the groups bigger and more irratic and pressure signs would definitely be visible... but you would also see a big jump in velocities which some shooters want.

When your load is right, using proper rests, and you are shooting well, this is the type of Vertical you can tune your rifle for. Again 250yds with a slight pick up in R to L mirage... otherwise, wind is calm. I didn't bother to hold off for the pick up. The 2 loads are not much different in final weight.
YMMV.

Jerry

Thanks for explaining more.

I recently developed a hunting load (previously using a ladder at 100 and version of your methods at 200 ) and last week sighted in at hunting temperatures out to 100. After sight in, I put on the magnetospeed to capture some numbers on another target. In my case the elevation stayed the same in terms of POI shift albeit a shift left by a half inch. I anticipated more shift in both x and y axis but only in the X. This is just a factory bolt gun, but not expected.

ES and SD numbers were disappointing yet the paper said different. Noted this isn't proven at 300 or over but I will mix some more up at plus minus .2 grains and see.

Best Regards
Ron

 

[Mystic Precision]

Let us know how the further distance testing goes. At 200 to 300yds, determine the most accurate load. Now load 0.2gr on either side and compare the ES/SD numbers vs the group size at 200 to 300yds.

See if the best group gives you the lowest ES/SD

Also, please note the location of the groups relative to the center of each aiming point. I am aiming dead center for all groups... location of the group moves around with no real pattern or orientation. This is why I do not use nor recommend the 1 shot OCW type testing.... doesn't always tell you what you want to know.

Jerry

 

[bearhunter]

I guess I had a similar experience. I have lots of Chrony brand units, because they gave them to me. I have shot 7 of them, but still have 3 or 4.

I discovered that if I tested on a cloudy day, results were excellent. On a blue sky, results were erratic. The sky screens may solve the problem, but I just wait for a cloudy day.

I live on a farm, and the ammo to be tested accumulated on a table by the back door. When it gets cloudy or overcast I step out into the back yard and do my testing.

If I could only test on Saturdays when I go to the range, this reliance on cloud cover would not be acceptable.

Just get a Magnetospeed and don't worry about light condition again. No, I'm not saying the speed they record is perfect but the round to round consistency is fantastic. The Magnetospeed is good enough to give you velocities at different temperatures as well in real life data.

With a bit of doping and a general idea of temperature influence on your components/rifle, some very accurate shots can be made at longer ranges.

My Magnetospeed has shown me how much velocity varies at different temps with the powder/primer combinations I find appropriate for hunting and target shooting under most weather conditions.

Last year I found out that a load which I presumed to be accurate even at -25C as well as +20C with a supposedly non temperature sensitive powder used over magnum primers was an average of 100fps slower.

This same load wasn't bothered by hotter conditions. Go figure.

Not a lot at closer ranges but enough to miss a Coyote at 200 yards without knowing why.

The Chrony might give me indicative readings if the light conditions were close to the original day I developed the final load.

It's very important to test loads under as many conditions as possible.

TURF THE LIBERALS IN 2019

Liberals really like POOR people, they're making more of them every day

If you can't vote CPC, stay at home in protest

 

[350 Mag]

If possible, test your scale to a quality milligram digi scale like a AND FX120I or Santorious or similar lab quality scale. Although the scale may read XYZ, you need to prove the mass that is actually in the pan. Do a sample size of 20 to 50 charges to confirm a trend.

If the scale proves to be reliable to the 0.1gr, AWESOME and treasure it.... if not, look for a remedy.

Of course, precise charge weights is just one part in a list of steps needed to make match grade ammo... but it is, to me, the most important step.

Jerry

The FX120 is $950....!!!

Any opinion on A&D EJ-200 its more affordable @ $340.

I recently purchased a runout gauge...and I have had good results so far with sizing brass with Lee Collet and Redding Body die....use a Redding competition seating dies(with VLD stem).

 

[Mystic Precision]

The FX120 is $950....!!!

Any opinion on A&D EJ-200 its more affordable @ $340.

I recently purchased a runout gauge...and I have had good results so far with sizing brass with Lee Collet and Redding Body die....use a Redding competition seating dies(with VLD stem).

Looks like the Fx120i pricing has taken a huge jump... crappy dollar. I have used this for several years and not tested anything else from their product line.

the die combo you are using will provide very good results... I also use Forster seaters.

I am sure there are other options for milligram scales but you will need to do your own testing and research.

Jerry

 

[Ganderite]

Just get a Magnetospeed and don't worry about light condition again. No, I'm not saying the speed they record is perfect but the round to round consistency is fantastic. The Magnetospeed is good enough to give you velocities at different temperatures as well in real life data.

With a bit of doping and a general idea of temperature influence on your components/rifle, some very accurate shots can be made at longer ranges.

My Magnetospeed has shown me how much velocity varies at different temps with the powder/primer combinations I find appropriate for hunting and target shooting under most weather conditions.

Last year I found out that a load which I presumed to be accurate even at -25C as well as +20C with a supposedly non temperature sensitive powder used over magnum primers was an average of 100fps slower.

This same load wasn't bothered by hotter conditions. Go figure.

Not a lot at closer ranges but enough to miss a Coyote at 200 yards without knowing why.

The Chrony might give me indicative readings if the light conditions were close to the original day I developed the final load.

It's very important to test loads under as many conditions as possible.

TURF THE LIBERALS IN 2019

Liberals really like POOR people, they're making more of them every day

If you can't vote CPC, stay at home in protest

Cold weather would be hunting with ammo developed in the summer. It might be quite mild and shoot low at longer ranges. Personally, all but one of my kills has been at less than 100 yards, so not a big concern to me.

What I have seen a lot of, and it is a more serious problem is guys developing their target loads in the spring, and then discovering that they are too hot in the summer - in an important match.

I take my spring ammo to the range in a picnic cooler. In the cooler are 2 two-liter bottles of hot tap water. This keeps the ammo quite hot. And I store the 5 or ten rounds to be shot in my shirt pocket - around 98 F.

If you ever find your self with ammo that is to hot (high pressure) to shoot, but have to shoot (in a match) a field fix is to smear a film of your bolt lug grease on the bullet ogive. This drops pressure about 5,000 psi.