PRS Talk How does being in a “node” actually matter?

[Dthomas3523]

So, here’s two examples:

Shooter A: does whatever load development he likes (ocw, chrono...whatever). And let’s say he’s found an actual true to life node. He’s got it all figured out. He goes to range and trues his dope.

Shooter B: loads whatever charge weight got him the velocity he wants. He has also gone to range and trued his dope.

Both shooters are loading on fx120 scales. Both guns are shooting .5moa or better at 100. Both using Berger bullets, lapua brass, good components etc.

Now here’s my question. If both shooters have a good BC for their bullet in their software, and have gathered dope correctly.

Basically everything the same except shooter A found a node and Shooter B loaded random charge weight (albeit it consistently on a good scale).

Can anyone give me any scenario where shooter B will be at a disadvantage at a match where shooter B chrono’d the day of or day before in the general area he will be shooting?

Can anyone give me an example in which shooter A’s time spent finding a node will give him any advantage over shooter B??

(None or this “you have to find a node” answers. Back up that statement with examples or data to show why)

 

[Mormegil87]

In the above scenarios wouldn't group size be the deciding factor? Or are we going off the assumption that groups sizes in each scenario are equal?

 

[Dthomas3523]

In the above scenarios wouldn't group size be the deciding factor? Or are we going off the assumption that groups sizes in each scenario are equal?

Let’s say group size is more or less the same.

Shooter B took the time to adjust seating depth(or didn’t and it happened to shoot well)

 

[samb300]

I'll answer your question with another question (because I don't have an answer).

WHY does a velocity flat spot, or "node", exist in the first place? Why would a charge range of 0.3 to 0.6 gr of powder yield the same velocity when logically adding powder linearly should increase velocity linearly? Isn't that where it would make sense to WANT to be?

Why are there sometimes powder charges where adding only 0.1gr nets you a significantly higher step up in velocity?

These are serious questions; internal ballistics experts please chime in LOL

If both shooters can throw to +/- 1 kernel (so roughly +/- 0.03gr) then I can't disagree that theoretically shooter A and B should have the same results for a single match. That's assuming no electronic scale drift over the course of loading ammo for the match. Will both shooters be able to shoot the same load over the course of the season, or will shooter B's need to be retuned before each match?

Another question; is a powder charge "node" dependent on the actual volume of powder, or the resultant velocity? Is the node still a node when you're shooting a temp sensitive powder and you go from 100F to 40F? Is the node still a node when the barrel wears and you lose velocity due to throat erosion?

I will also add, the "node" method used may matter as well. The 10-shot Satterlee method is flawed IMO, even with a 1-kernel scale, due to being only 1 shot per charge weight. And the OCW method relies more on barrel tuning and POI shifts; generally velocity isn't even considered.

 

[Mormegil87]

@Dthomas3523 then I have no reasonable scenario or data to show, in which Shooter B is at a disadvantage. I've done it both ways with good results.

 

[D_TROS]

Barrels when shot act like a sinusoidal wave as the energy goes down the barrel. Barrel whip if you will. Similar to if you grab the end of a jump rope and wave your hand up and down.

This is important for a few reasons. First of all, we cant just guess when/where/how its going to effect accuracy. We have to shoot to find it. YES we can get lucky and have the wave match up for optimal accuracy.

This is where it matters. As the barrel whips up and down (pending amount of powder, seating depth, bullet weight, powder type, barrel thickness, barrel length, annealing, primers, etc etc) the barrel is going fastest between the peak and trough of the wave (middle of wave) and going the slowest AT the peak and trough (top & bottom) as the wave switches directions.

This is the vital nodes we want. The peak and trough. We want the barrel moving the slowest to not affect the bullet as it exits AS MUCH if anything above in red is not perfect the same. Think extreme small amount of time, if you are off by a millisecond the barrel will throw the bullet less when it is switching directions, essentially not moving much as opposed to when the barrel is flying in the middle. When the barrel is moving fast the same delta time will affect group size more...


Now we affect the harmonics for the node when it switches directions by adjusting all the things we adjust mentioned above in red. IE load workup.
What this essentially does is decrease user error while still be able to maintain accuracy.

In your example if the powder is dropped to the exact kernal would it matter? Absolutely potentially...lol. You still have to depend on consistencies in the rest of your stuff. In these day and ages with fantastic compute tech in production lines the quality control is SOOOO high most components are no longer the weakest link so load workup is mattering less and less. BUT while it may work I would not hold my breath to it.

So yes you could get away with throwing in powder and have a great shooting weapon. End of day, what are your expectations and how precise are you being. As a competitor I will absolutely do load work up as I want to have as much room for error as possible.


Regards
DT

 

[Dthomas3523]

Barrels when shot act like a sinusoidal wave as the energy goes down the barrel. Barrel whip if you will. Similar to if you grab the end of a jump rope and wave your hand up and down.

This is important for a few reasons. First of all, we cant just guess when/where/how its going to effect accuracy. We have to shoot to find it. YES we can get lucky and have the wave match up for optimal accuracy.

This is where it matters. As the barrel whips up and down (pending amount of powder, seating depth, bullet weight, powder type, barrel thickness, barrel length, annealing, primers, etc etc) the barrel is going fastest between the peak and trough of the wave (middle of wave) and going the slowest AT the peak and trough (top & bottom) as the wave switches directions.

This is the vital nodes we want. The peak and trough. We want the barrel moving the slowest to not affect the bullet as it exits AS MUCH if anything above in red is not perfect the same. Think extreme small amount of time, if you are off by a millisecond the barrel will throw the bullet less when it is switching directions, essentially not moving much as opposed to when the barrel is flying in the middle. When the barrel is moving fast the same delta time will affect group size more...


Now we affect the harmonics for the node when it switches directions by adjusting all the things we adjust mentioned above in red. IE load workup.
What this essentially does is decrease user error while still be able to maintain accuracy.

In your example if the powder is dropped to the exact kernal would it matter? Absolutely potentially...lol. You still have to depend on consistencies in the rest of your stuff. In these day and ages with fantastic compute tech in production lines the quality control is SOOOO high most components are no longer the weakest link so load workup is mattering less and less. BUT while it may work I would not hold my breath to it.

So yes you could get away with throwing in powder and have a great shooting weapon. End of day, what are your expectations and how precise are you being. As a competitor I will absolutely do load work up as I want to have as much room for error as possible.


Regards
DT

So, give me an example of what can go wrong for shooter B?

He has consistent chrono numbers and group size. He has a good BC for his bullet. But he didn’t do any load testing beforehand. I.E. didn’t load bunch of charges in .2 or .3 increments.

Explain what/how can go wrong for shooter B. It’s very hard nowadays to load on a good scale with good components and have a very high ES (enough to matter on prs size targets).

 

[Dthomas3523]

Or, here’s another challenge.

Do load work up and find your “nodes.”

Now, take a charge weight that isn’t in one of the nodes. Load it, and if it doesn’t shoot the group size you want, tune the seating depth.

Now go true the dope and put it in your calculator.

Go practice with that load or shoot a match with it and find the reasons it doesn’t work as good as the load developed nodes.

 

[Olen_4504]

I think it would only benefit someone that doesn’t get consistent charge weights/velocities. Whatever the reason may be (cheap scale, etc)

Then finding a node would be most beneficial, right? It would absorb the fluctuations in speed due to inconsistent charge weights

Other than that there isn’t really a NEED to be in a node. Unless you just want piece of mind that your load can absorb any fluctuations whatever they might be.

I bring up nodes when people are comparing their CM numbers to the v3 numbers and that it really doesn’t matter. Especially if you are in a node. But if you aren’t, but if the unit is throwing halfway consistent, then it doesn’t matter really.

 

[Olen_4504]

I didn’t mean to write charge weights/velocities. Just charge weights. The pint of the node would be consistent velocities regardless of not so consistent charge weights

 

[Nomad_chew]

I think it’s more about efficiency. Like OCW is really about getting the best performance out of a round, right? The way I understand is those nodes are just were everything is the most efficient and everything is working together.

 

[CoryT]

The only real issue is consistent vertical over a possible variation in ammo/conditions. Depending on how well the load handles temperature shifts, bullet weight/bearing surface differences, charge weight errors, it may not matter at all. The only point of the process is to give you more margin for error. If you load like it's for benchrest, it's probably not relevant. If you just stick bullets in cases after scooping up a case full of powder, it's probably helpful.

 

[samb300]

A Chargemaster is listed as +/- 0.1gr, and depending on your unit and modifications and willingness to use overthrows it may or may not be that good.

An A&D FX-120i has a resolution of 0.02gr, but a linearity of +/- 0.04 gr (the specs actually call out 0.001g and +/- 0.002g). So while the FX-120i with AutoTrickler is considered the gold standard, it really is +/- 0.04gr, while displaying on screen to 0.02gr.

A Prometheus is +1 kernel / -0 kernel.

Could using a Chargemaster affect disbursement shot-to-shot? Yes. In most PRS-scenarios does it matter? No. One could argue that being in the middle of even a +/- 0.1gr powder node would yield more consistent ES numbers when using a typical thrower like the Chargemaster. If you have an FX-120i or Sartorius-64 or Prometheus, then like you said, it likely won't matter.

 

[Rant Durden]

The one thing I've noticed within the nodes is my SD is usually lower. Not always, but in general I get better SD within the node than outside.

 

[Dthomas3523]

The one thing I've noticed within the nodes is my SD is usually lower. Not always, but in general I get better SD within the node than outside.

That doesn’t matter in the context of this question.

When you’re not in the node, is your SD high enough to matter on practical size targets?

 

[Huskydriver]

I see it playing a factor when you don't know if your barrels about to start speeding up in the throat mid session on you. If your in a wide node all else being equal vs a guy who isn't, your less likely to see vehicle stringing causing misses....or wait for it.... Your a guy like me who didn't doesn't clean his barrels very often .

Also I could see the same scenario in a wide temp swing mid match which is very common in the rockies. If your in the middle of the velocity node your less likely to see as severe of a vehicle shift

 

[SSSamurai]

I load on the low end of a node so that pressure increases driven by high temperatures or moisture on the cases will (hopefully) move me up the node while keeping inside it. That's the theory anyway...

 

[Meety Peety]

I dont have an answer but my question would be what happens if shooter B picks a random charge that happens to be right at the upper edge of a node (so it shoots fine and numbers appear to be good) and then he goes out and shoots a match where its 100+ degrees with no shade and his barrel never gets a chance to really cool down between stages (let's say he doesn't have a towel either). Does his load run hot all day and does that push him out of the "node" he happened to be in causing groups to open up and numbers to start climbing? If shooter A was at the same match but his load was in the center of the node, does his load hold up while shooter B's load falls apart? Suppose the opposite scenario could exist with an extreme low temp as well.

I don't know the answer to these questions, but I'm not sure I see much value (For me) in finding out the hard way. I just do enough to feel confident that my ammo is going to shoot the same or close to it under a number of different conditions and go with that. Its pretty minimal and it doesn't seem to me like skipping that step would be worth saving a few rounds on the barrel. I guess if you are one of those guys who eats up half the barrel life chasing a .25" load then it might be different.

 

[samb300]

Can anyone give me an example in which shooter A’s time spent finding a node will give him any advantage over shooter B??

The one thing I've noticed within the nodes is my SD is usually lower. Not always, but in general I get better SD within the node than outside.

To be fair...define "advantage". Is a lower SD an advantage? Yes it can be, but not really at a <600yd PRS club match. What if this is for the Nightforce ELR match which has an average target of 1100 yds or something like that?

So then it is up to the shooter understand what it actually important for their discipline, and choosing whether or not to pursue the incremental improvements that might not actually matter.

If your argument is that none of this matters for PRS, then I would say just shoot factory 6 creed and be done with it. Why even bother reloading in the first place? Other than some increased recoil, 6 creed gives up nothing to a meticulously loaded 6 Dasher. (I'm being Devil's advocate here)

 

[TxWelder35]

I believe this is what Bryan/Amil we’re talking about in one of the no bs BC podcasts with Frank, he was saying he never bothers looking for a node, he finds the velocity and es/sd numbers he wants and then goes from there. Said it was more important for every charge to be thrown perfect to the kernel than to be in a node.

 

[Rant Durden]

That doesn’t matter in the context of this question.

When you’re not in the node, is your SD high enough to matter on practical size targets?

I'm still learning about what makes a difference and what doesn't. I don't have regular access to long range targets, but will be going to the Guardian in Az end of the month so I guess we'll see if I chose correctly.
From what I understand group size and SD count more the farther you have to shoot. My limited access to ranges beyond 100 yards and the fact that my reloading teacher isn't all that interested in finding nodes limits how much research I can do within said nodes.
That said, the proof is on the target(s). If the group is acceptable and the SD is good for your desired distance, I'm not sure nodes matter at all.
So in the context of this question, it doesn't seem to matter at all.

 

[Mormegil87]

Factory ammo could be a good indicator of what @Dthomas3523 is asking. If it groups well and has relatively consistent velocities. Does being in a "node" even matter?

 

[Huskydriver]

Factory ammo could be a good indicator of what @Dthomas3523 is asking. If it groups well and has relatively consistent velocities. Does being in a "node" even matter?

I understood Fgmm and m118lr are loaded to where they are loaded because they are in the best node possible given the coal/bullet weight for the lot of powder being used def no proof that though

 

[2aBaC̶a̶]

Its hypothetical luck that shooter B just picked a good load. He obviously did some workup on speed. Verified with groups and velocities.

The way I see it being in the node reduces the overall likelihood of all other factors combined having a noticeable effect on performance. Think stacking tolerances.

What is your SD and ES of tolerances on things like Headspace, neck tension, powder throws, seating, neck and bullet runout, case volume, weights, annealing, etc?

It adds up.

My guess is the more control you have over those tolerances the less critical it is to be in the center of a node.

On top of that add environment factors like temp, humidity, and altitude.

 

[TheOfficeT-Rex]

Basically everything the same except shooter A found a node and Shooter B loaded random charge weight (albeit it consistently on a good scale).

Can anyone give me any scenario where shooter B will be at a disadvantage at a match where shooter B chrono’d the day of or day before in the general area he will be shooting?

No, because the results downrange are "acceptable" in both instances.

Can anyone give me an example in which shooter A’s time spent finding a node will give him any advantage over shooter B??

Extreme temperature variation or equipment inconsistency. How much of either would push results to unacceptable levels? That's so subjective and equipment/component/load/accuracy requirement dependent that we'll never agree on an answer.

 

[Dthomas3523]

Its hypothetical luck that shooter B just picked a good load. He obviously did some workup on speed. Verified with groups and velocities.

The way I see it being in the node reduces the overall likelihood of all other factors combined having a noticeable effect on performance. Think stacking tolerances.

What is your SD and ES of tolerances on things like Headspace, neck tension, powder throws, seating, neck and bullet runout, case volume, weights, annealing, etc?

It adds up.

My guess is the more control you have over those tolerances the less critical it is to be in the center of a node.

On top of that add environment factors like temp, humidity, and altitude.

Not at all luck.

I can take my dasher, 6br, 6x47 (and 6gt when I had it).

I can pick any random charge weight and throw it with fx120. I can load a berger bullet .020 off lands. It will be under 40 ES and will easily shoot under 1moa and most of the time .5 moa or so.

Are you suggesting that this won’t be consistent enough to take to anywhere in the country, chrono before a match, and it wouldn’t perform?

 

[kindabitey]

No advantage to either shooter.
Just my opinion, but the quality of reloading products and weighing/ powder measuring equipment we have today just doesn't jive with the methods of yesterday.

 

[Precision Underground]

When you’re shootings truck axel barrels, harmonics are not really much of a factor. Loading for thin barrels is a lot different. Most of the time a load test on a thick barrel doesn’t have a lot of POI variations. On the thin barrel I can watch it go left, right, up, down through different charge weights. So in that scenario you’re looking for the point in the wave where the barrel is changing directions as that will give you the widest window to find the same POI. Then if powder charge, temp, or any other factor that affects velocity changes, your POI won’t change. The only real world evidence I have is looking at load test targets and watching the POI shift. I always pick the best node so I dont have any data on what happens if you choose the edge of a node

 

[stello1001]

You find a node so that small variables or changes in environmentals or loading techniques do not affect you downrange.

Shooter B is gonna have serious consequences when he goes shoot somewhere and there is a change in temp, altitude, etc. Shooter A will be next to shooter B but because he is in a large wide node, his load will still be shooting very good...

 

[2aBaC̶a̶]

Not at all luck.

I can take my dasher, 6br, 6x47 (and 6gt when I had it).

I can pick any random charge weight and throw it with fx120. I can load a berger bullet .020 off lands. It will be under 40 ES and will easily shoot under 1moa and most of the time .5 moa or so.

Are you suggesting that this won’t be consistent enough to take to anywhere in the country, chrono before a match, and it wouldn’t perform?

If you can do that then I guess the question becomes is finding a node really neccesary and if so under what circumstances?

 

[Nomad_chew]

Not at all luck.

I can take my dasher, 6br, 6x47 (and 6gt when I had it).

I can pick any random charge weight and throw it with fx120. I can load a berger bullet .020 off lands. It will be under 40 ES and will easily shoot under 1moa and most of the time .5 moa or so.

Are you suggesting that this won’t be consistent enough to take to anywhere in the country, chrono before a match, and it wouldn’t perform?

Inherently those are accurate rounds. I would argue, yes, they would be consistent enough to compete.

 

[Dthomas3523]

Inherently those are accurate rounds. I would argue, yes, they would be consistent enough to compete.

We are in the PRS section here.

So, we are talking 6.5cm 6cm, 6.5x47 6x47 6gt 6br (and variants).

If we start talking other things, that may or may not be a different conversation.

 

[Dthomas3523]

If you can do that then I guess the question becomes is finding a node really neccesary and if so under what circumstances?

This is basically my question.

For the most part, it’s very hard to load shitty ammo if you use quality equipment or components.

So, for practical/prs purposes, at what point are you getting something out of your load development and at what point are you virtually wasting time?

For example, the current NRL points champion says he hasn’t measured a chamber or done load development in 7 barrels.

 

[Nomad_chew]

You just said it. I shot 6.5 CM for a couple years in PRS and like you said it was always good enough, so I stopped chasing the nodes. Spent way to much time and coin chasing the “SD/ES” or “velocity”.

 

[Dthomas3523]

You find a node so that small variables or changes in environmentals or loading techniques do not affect you downrange.

Shooter B is gonna have serious consequences when he goes shoot somewhere and there is a change in temp, altitude, etc. Shooter A will be next to shooter B but because he is in a large wide node, his load will still be shooting very good...

Explain how shooter B will have an issue if he travels to location X.....and runs his chrono at location X.

So, he already had his BC figured out. He now has his new velocity for location X.

His load isn’t going to all of a sudden from 40 ES to a 100 ES going to location X. His group size also isn’t gonna go from .5 to 1.5”. These types of changes just don’t happen with modern components. They change, but the change is much smaller than it was in circa 1990 when nodes were a thing.

If his velocity at Location A was 2900 and he goes to location X and chronos at 2950.....he has already solved the puzzle for temp, elevation, etc etc.

 

[Dthomas3523]

The main point of this post is to have people actually look at the why behind what they are doing.

Almost every post is basically you “should” do it, without anyone actually being able to explain how they have tested these “shoulds.”

I’ve dug into the weeds for thousands of rounds. I have everything from IDOD neck turners, hydro presses, neo mini front rests and rear bags......etc etc.

I’ve run thousands of rounds with full load development and thousands without. As well as some in between.

I’ve see what makes big differences and what makes small or no differences. And I’ve adjusted my loading accordingly for the discipline I’m shooting.

I’d suggest everyone test what they think they “should” do. Some of this stuff is circa 1990 and some isn’t. Some will make a big difference and some won’t.

 

[Supersubes]

I’m traveling now so I can’t post any targets for the next week or so. I like the OCW method, but I’ve always though doing it at 100 yds is just stupid. Not enough resolution. When done at distance, point of impact does NOT track in a linear fashion with the velocity increase. So on the edges of the node and into scatter, very small increases(or decreases) in velocity create much more vertical than the velocity would suggest.

@Dthomas3523 it would be easy for you to test on an existing rifle of yours. .2 gr increments(6-7 different charge weights), three rounds each charge ending at what you’d consider a hot but safe load, fired round robin from a cold barrel at 500-600 yards. See what it looks like and compare it to what you’re shooting now. I use poster board and color the ogives of each charge with a sharpie. Paste an aim point that you like at the bottom. Fire a few sighters to make sure you’re on and run it. My guess is that you’ll see what I see, but it will be up to you whether or not that vertical jumps are worth avoiding or not. Sometimes you can see the group forming but don’t pay attention to it. Treat is like live fire prone fundamental practice.

 

[Mordamer]

"Flat spots" in a velocity vs. powder charge graph are statistically irrelevant. Do the same test 3 times and you'll find a different "node" each time. Unless you are taking a sample of about 20 shots at each powder charge your velocity numbers are totally bogus. If you are taking a sample of 20 shots at each charge your barrel probably changed speeds during the test. Haha

 

[Mormegil87]

@Dthomas3523 exactly. Just for shits and giggles, I went out with my BRA and did a Satterlee test to see what velocities looked like. Wouldn't you know it, for every increase in charge weight, there was a corresponding increase in velocity. So I picked one in the speed im looking to run and thats what im going to use at our regional finale this weekend.

Mark Gordon's research and subsequent interview have really made me take a long hard look at how I do load development. As well as a long look into my loading procedure.

 

[Mordamer]

Also, the same goes for "ladder tests" and OCD tests where only 3 shots are fired per charge weight. These tests are only useful to psychologically reinforce to the test performer that they are using the right load.

 

[Dthomas3523]

I’m traveling now so I can’t post any targets for the next week or so. I like the OCW method, but I’ve always though doing it at 100 yds is just stupid. Not enough resolution. When done at distance, point of impact does NOT track in a linear fashion with the velocity increase. So on the edges of the node and into scatter, very small increases(or decreases) in velocity create much more vertical than the velocity would suggest.

@Dthomas3523 it would be easy for you to test on an existing rifle of yours. .2 gr increments(6-7 different charge weights), three rounds each charge ending at what you’d consider a hot but safe load, fired round robin from a cold barrel at 500-600 yards. See what it looks like and compare it to what you’re shooting now. I use poster board and color the ogives of each charge with a sharpie. Paste an aim point that you like at the bottom. Fire a few sighters to make sure you’re on and run it. My guess is that you’ll see what I see, but it will be up to you whether or not that vertical jumps are worth avoiding or not. Sometimes you can see the group forming but don’t pay attention to it. Treat is like live fire prone fundamental practice.

I’ve tested this to death.

I’ve personally never had anything that shot acceptable at 100, not work out to 1100.

If it doesn’t hold out to that distance, it’s your bullet to bullet BC variance. Not your charge weight or anything else.

 

[Dthomas3523]

I’m traveling now so I can’t post any targets for the next week or so. I like the OCW method, but I’ve always though doing it at 100 yds is just stupid. Not enough resolution. When done at distance, point of impact does NOT track in a linear fashion with the velocity increase. So on the edges of the node and into scatter, very small increases(or decreases) in velocity create much more vertical than the velocity would suggest.

@Dthomas3523 it would be easy for you to test on an existing rifle of yours. .2 gr increments(6-7 different charge weights), three rounds each charge ending at what you’d consider a hot but safe load, fired round robin from a cold barrel at 500-600 yards. See what it looks like and compare it to what you’re shooting now. I use poster board and color the ogives of each charge with a sharpie. Paste an aim point that you like at the bottom. Fire a few sighters to make sure you’re on and run it. My guess is that you’ll see what I see, but it will be up to you whether or not that vertical jumps are worth avoiding or not. Sometimes you can see the group forming but don’t pay attention to it. Treat is like live fire prone fundamental practice.

I also don’t use groups or poi or anything on paper *at all* to choose a charge weight.

If I’m doing load development, I use a chrono for charge weights. Once I’ve picked the charge weight, I don’t change it based on the bullet or paper. I change seating depth and such and work it out that way.

 

[stello1001]

Explain how shooter B will have an issue if he travels to location X.....and runs his chrono at location X.

So, he already had his BC figured out. He now has his new velocity for location X.

His load isn’t going to all of a sudden from 40 ES to a 100 ES going to location X. His group size also isn’t gonna go from .5 to 1.5”. These types of changes just don’t happen with modern components. They change, but the change is much smaller than it was in circa 1990 when nodes were a thing.

If his velocity at Location A was 2900 and he goes to location X and chronos at 2950.....he has already solved the puzzle for temp, elevation, etc etc.

Shooter B could have his new velocity into the software which is going to give him his new drops. However, if he was never in a node to begin with, it's possible his POI or drops are not going to be very consistent.

I'm no expert so I could very well be wrong. But I'm just posting what I believe. I also came in to this thread because it seems interesting and I could probably learn some. I wanna see what you have to say at the end.

 

[Dthomas3523]

Shooter B could have his new velocity into the software which is going to give him his new drops. However, if he was never in a node to begin with, it's possible his POI or drops are not going to be very consistent.

I'm no expert so I could very well be wrong. But I'm just posting what I believe. I also came in to this thread because it seems interesting and I could probably learn some. I wanna see what you have to say at the end.

Here are my findings and opinions. Take special note that this is for the practical/prs shooting crowd. F class and BR stuff is a different conversation.

Modern scales, chronos, and components have made nodes much less necessary than they used to be. We used to have shitty light chronos, cheap beam scales, and lesser components than we do now.

So, being in a node helped make up for the stacking of all of this.

We didn’t have a magneto or labradar we could put in our pack and take wherever we want to get the current velocity. The two main things in external ballistics (for our purposes) is velocity and BC.

So, here is what I have (and many others before me and smarter than me) have concluded for our purposes:

Most (not all) of your ES and such is going to be your powder drop. Followed by your neck tension. If you are using a good scale and consistently getting your neck tension where you want it.....you will find it very hard to make ammo shitty enough to miss the targets we shoot at. (I’ll post a pic of the load development for charge weight I did for a barrel. Even if I doubled those numbers, it wouldn’t matter)

MV is broken into two parts for us. 1: consistency and 2: value. We just solved our consistency part with a good scale and good neck tension/brass prep practices.

To solve for the value, we have magnetospeed and labradars.

There is our velocity requirement for external ballistics.

Now, BC. We figure this by taking real world data and truing our software. This is common knowledge. I won’t bore anyone with this.

So, let’s say we loaded a random charge weight in our dasher and it has a 40 ES with 2950 MV and we trued the BC to .292. We have solved the equation for extrenal ballistics.

(I also challenge anyone to seat a berger bullet .20-70, maybe more. In any powder charge that isn’t over pressure and shoot a group that’s over an moa. It’ll likely be closer to .5 than it is to 1)

Now, let’s say we take the exact same random load to bumfuk wherever. Circa 1990, we had no idea how fast it was going. So we needed to be in some sort of general node where our velocity didn’t fuck us over. Now, we pull our magneto and see that because of temperature, or whatever, our speed is now 2900. That’s not going to be enough to mess with our BC, so that is still solved. Our calculators solve for our current elevation from sea level. Our Berger bullets will still be shooting .5-1 somewhere. Perhaps you need to adjust zero slightly, but probably not.

The solution is again solved. We have our MV and BC and our rifle is zero’d and accurate enough to easily hit the size targets we are after.

So, my opinion, if you have time and want to do some charge weight development, go for it. If you have shitty equipment, shitty components, no chrono.......or for some weird reason you may have to pick up your rifle and go from location A to location B, without being able to chrono it.....look for a node.

But, if you have good equipment and components, along with a good chrono, you can save yourself a ton of time just picking a speed you’d like to be at, adjust seating depth if need be, get your data trued and done to where the only input you need from location to location is your MV. You won’t be at any disadvantage in this game.

I person load what charge I want (running 30.0 in dasher), load .020 off lands, and use my EC tuner to replace seating depth to dial groups in.

I have seen absolutely zero reason to go back and pour over data to find a “node” in my prs rifles unless I have time and decide to do it.

Here is some data. If anyone can tell me why you couldn’t pick any powder charge from this chart and tune seating depth, feel free:

 

[1moaoff]

Environmental swings the day of shooting

 

[phlegethon]

@Dthomas3523 I couldn't agree more, although I will point out that 36 grains of Varget in Dasher comes out to be around 80k PSI in my software...

 

[Supersubes]

I also don’t use groups or poi or anything on paper *at all* to choose a charge weight.

If I’m doing load development, I use a chrono for charge weights. Once I’ve picked the charge weight, I don’t change it based on the bullet or paper. I change seating depth and such and work it out that way.

I’m familiar with your method, but you're asking about this method, and you could answer the question for yourself in 20-25 rounds. Not a difficult process. In one string of fire you found max charge, found accuracy, and found a forgiving charge range. Consider you’re starting with a new barrel. All that left is seating depth. For me I pretty much know where I want to be anyway, and don’t have to change much at all.

edit: Regarding your charge test, as I said earlier, those won’t print in a linear fashion up the target, but ranges of them will cluster together. You said in essence in that same post that you may need to rezero and you need a chrono. This is what we'd like to avoid.

 

[Precision Underground]

Here are my findings and opinions. Take special note that this is for the practical/prs shooting crowd. F class and BR stuff is a different conversation.

Modern scales, chronos, and components have made nodes much less necessary than they used to be. We used to have shitty light chronos, cheap beam scales, and lesser components than we do now.

So, being in a node helped make up for the stacking of all of this.

We didn’t have a magneto or labradar we could put in our pack and take wherever we want to get the current velocity. The two main things in external ballistics (for our purposes) is velocity and BC.

So, here is what I have (and many others before me and smarter than me) have concluded for our purposes:

Most (not all) of your ES and such is going to be your powder drop. Followed by your neck tension. If you are using a good scale and consistently getting your neck tension where you want it.....you will find it very hard to make ammo shitty enough to miss the targets we shoot at. (I’ll post a pic of the load development for charge weight I did for a barrel. Even if I doubled those numbers, it wouldn’t matter)

MV is broken into two parts for us. 1: consistency and 2: value. We just solved our consistency part with a good scale and good neck tension/brass prep practices.

To solve for the value, we have magnetospeed and labradars.

There is our velocity requirement for external ballistics.

Now, BC. We figure this by taking real world data and truing our software. This is common knowledge. I won’t bore anyone with this.

So, let’s say we loaded a random charge weight in our dasher and it has a 40 ES with 2950 MV and we trued the BC to .292. We have solved the equation for extrenal ballistics.

(I also challenge anyone to seat a berger bullet .20-70, maybe more. In any powder charge that isn’t over pressure and shoot a group that’s over an moa. It’ll likely be closer to .5 than it is to 1)

Now, let’s say we take the exact same random load to bumfuk wherever. Circa 1990, we had no idea how fast it was going. So we needed to be in some sort of general node where our velocity didn’t fuck us over. Now, we pull our magneto and see that because of temperature, or whatever, our speed is now 2900. That’s not going to be enough to mess with our BC, so that is still solved. Our calculators solve for our current elevation from sea level. Our Berger bullets will still be shooting .5-1 somewhere. Perhaps you need to adjust zero slightly, but probably not.

The solution is again solved. We have our MV and BC and our rifle is zero’d and accurate enough to easily hit the size targets we are after.

So, my opinion, if you have time and want to do some charge weight development, go for it. If you have shitty equipment, shitty components, no chrono.......or for some weird reason you may have to pick up your rifle and go from location A to location B, without being able to chrono it.....look for a node.

But, if you have good equipment and components, along with a good chrono, you can save yourself a ton of time just picking a speed you’d like to be at, adjust seating depth if need be, get your data trued and done to where the only input you need from location to location is your MV. You won’t be at any disadvantage in this game.

I person load what charge I want (running 30.0 in dasher), load .020 off lands, and use my EC tuner to replace seating depth to dial groups in.

I have seen absolutely zero reason to go back and pour over data to find a “node” in my prs rifles unless I have time and decide to do it.

Here is some data. If anyone can tell me why you couldn’t pick any powder charge from this chart and tune seating depth, feel free:

View attachment 7450216

I don’t look for a node for SD/ES. POI is what I’m looking for. Again, if you have a fat barrel that harmonics won’t affect much it may not matter. But I’ve shot enough load tests on gas guns with .750 barrels to know the POI moves around significantly with different charge weights. If you pick a random load you may end up .1 away from a POI shift and that’s not where I want to be. I usually know about how fast I want to run a bullet so I load charges around that target velocity and skip the ones I know I’m not going to use. It literally takes 25-35 rounds at the most to confirm a consistent POI so to me that makes way more sense than just picking a charge. If they all print the same POI then I haven’t lost anything. A barrel needs 100 rounds to break in anyway. That being said I do agree that loading 5 rounds of an entire acceptable range in .2 grain increments is a waste of time and components. I know I’m not going to use 140s at 2620 FPS so I don’t care how it shoots.

 

[Precision Underground]

eyou may need to rezero and you need a chrono. This is what we'd like to avoid.

This x100. I set a zero on a rifle/load and it doesn’t change. If I need to change my zero I’m looking for what went wrong.

 

[Campguy308]

For example, the current NRL points champion says he hasn’t measured a chamber or done load development in 7 barrels.

What is his method? Load to the speed he wants?