Optimum barrel time: great theory or bunk?

[Bbracken667]

I think much of the confusion people experience resulting in the complete lack of load development is the absolute lack of reliability regarding statistical analysis when one is only looking at 3 shot or 5 shot groups when 35 should be an absolute minimum to produce reliable data.
I like the concept of OBT and will answer the question for me, but I believe it will be months before I am satisfied one way or another. I am going with the long game here and will only draw conclusions when there is sufficient data to make a decision.
Anything else is voodoo science or religion (I believe)

 

[CK1.0]

more/less fuel = more/less speed, always.

Rorschach test - Wikipedia

en.wikipedia.org

 

[Macht]

I'll try and hit multiple questions with one post:

What does that leave to explain bullets that perform materially better at multiple discrete seating depths, but poorly in between?


Any links to this available?

I'd haven't seen anything but anecdotes suggesting that the behavior you describe exists, certainly nothing with statistically significant samples sizes or repeated testing. Even if it is a provable, repeatable phenomenon, the internal ballistic process is extremely complex. It could be related to degree of primer-induced debulleting, minimizing tilt in engraving, changing initial engraving force, etc. keeping in mind that each of those things are also dependent on each other. These it no reason to leap to the conclusion that the only thing affected by seating depth is barrel time. The Long paper and the updates to his theory you mention remind me of a Sherlock Holmes/Arthur Conan Doyle quote that Litz posted a while back: "It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories instead of theories to suit facts."

I don't have a direct link, but it was one of the more recent Hornady podcasts he was on, likely the barrel one. Might be on his website too, Bulletology.com

Long has evolved his theory (but has not updated his paper)... as I understand it, he still focuses on the Poisson effect, but has moved away from frictional load & now focuses on combustion gasses at the time the bullet exits the barrel (10:21-15:30 from the Podcast). Specifically, bore diameter changes/inconsistencies near the muzzle around the time of the bullet's exit allows the combustion gasses to destabilize the projectile.

If Long's theory is correct (& my understanding thereof), the goal is to find a load that appropriately times the bore diameter for consistency, thereby allowing for the bullet to exit when any impulses that induce/cause bore diameter variances have traveled back towards the chamber. Correct me if I've misunderstood something...

@Macht did you complete/publish your paper(s)?

As I mentioned in my first post, for a theory that hinges on predicting exactly when a stress wave arrives at the muzzle you would think you would want to model the behavior accurately. Hint: it's not by using the textbook number for speed of sound in steel. It would also be unlikely that one load would work well in so many different lengths of barrel, or that people with good reloading components, tools, and techniques can pick nearly any load and length that produces a safe pressure and get good results.

I did, along with my dissertation. I'll PM you links. You'll not likely find anything that directly deals with this question here, but you might find them interesting. If I could go back, I likely would have approached the problem differently.

It also seems like the OBT concept has been thoroughly validated: i.e. There is an optimum time for the bullet to exit the barrel. Bullet group dispersion on targets that change with velocity demonstrate this clearly. Why this happens is the question.

Your last statement contradicts the first; it can't be validated if we don't know the why. There is absolutely an optimum time for the bullet to exit the barrel: exactly the same amount of time as every other bullet you plan to shoot. Your statement above is a non-sequitur. Changes in group dispersion (if real, see comment above about statistically significant sample sizes) with change in velocity only tells you that adding or subtracting powder is affecting dispersion, it gives you nothing about the why. It could be/is affecting ignition, burn, in-bore tilt, de-bulleting behavior, muzzle blast, recoil, etc. Aero jump and lateral throwoff both increase with velocity. With so many factors at play, it seems foolish to somehow jump to the conclusion that the timing of projectile exit is the key.

Also, group dispersion that changes with coal.

See my responses above, apparent changes in dispersion with seating depth are often related to small sample size testing. In cases where it is not, there are any number of small factors that it affects that could be equally responsible for changes seen on target.

 

[Maxduty]

TLDR
Meh Frank Green says you'll ruin it cleaning it improperly. I wouldn't worry about it.

 

[4O6shootist]

Obt has been close with some my rifles, 30-50 fps off with others. I just shoot ladders at 500y. Find the velocity band with tight vertical dispersion. This is the theory of positive compensation, and it works.

 

[R_A_W]

The only real thing the Satterlee method is good for is for finding approximate velocities per charge weight, and where pressure occurs. But then that's not the Satterlee method, it's just a simple charge ladder.

Edit: I was wrong, ignore my Satterlee comments

Yes! You’re approximately arguing my point.

Regardless of what the Satterlee method purports to discover, it provides a simple structure for amateur reloaders to develop safe loads by testing charge weights first, then seating depths second.

It’s just a specific name for a definite basic process that people can recommend and the uninitiated can google. In that regard, it is great (IMO).

I wouldn’t overthink it, just consider it analogous to bowling bumpers

 

[kthomas]

Yes! You’re approximately arguing my point.

Regardless of what the Satterlee method purports to discover, it provides a simple structure for amateur reloaders to develop safe loads by testing charge weights first, then seating depths second.

It’s just a specific name for a definite basic process that people can recommend and the uninitiated can google. In that regard, it is great (IMO).

I wouldn’t overthink it, just consider it analogous to bowling bumpers

My argument is that the premise to the Satterlee method is garbage.

However, to your point, I made really good ammo for years using the Satterlee method. Not because of the method, but despite of it. Turns out I could make ammo from any given charge weight from the ladder, "velocity node" or not, and come out making good ammo.

People aren't making good ammo because of the Satterlee method, their making good ammo despite the Satterlee method.

You can definitely make good ammo using the Satterlee method. Just don't be fooled into thinking the "velocity nodes" are real nodes.

 

[kthomas]

But to the central premise of your point, all I do these days is a basic ladder to get an idea of velocity per charge weight, and to find pressure.

After that I load up ammo to what velocity I want to achieve. Easy peasy. 1/4-1/3 MOA ammo with SD's of 5 fps or less.

 

[R_A_W]

Edit: I was wrong, ignore my Satterlee comments

A helping hand:

Regardless of what the Satterlee method purports to discover, it provides a simple structure for amateur reloaders to develop safe loads by testing charge weights first, then seating depths second.

 

[secondofangle2]

It would be easy enough to have people post their loads that shoot really well and go and compare them to the predicted results from the OBT calculators in retrospect, rather than as load development

My guess is the shit would be all over the board without any statistically significant predictive value to OBT for empirical results

 

[R_A_W]

@kthomas I may have to eat crow, I thought the Satterlee method specified a 2 part test, first charge weight testing in 0.2gr increments & then seating depth testing in 0.005” increments

I’ll check back in tomorrow

Edit - yeah, I was way off. I don’t know where I got the idea above. Everyone should ignore my Satterlee method comments.

 

[kthomas]

@kthomas I may have to eat crow, I thought the Satterlee method specified a 2 part test, first charge weight testing in 0.2gr increments & then seating depth testing in 0.005” increments

I’ll check back in tomorrow

The Satterlee method was loading up ~10 rounds of incrementally increasing charge weights, shooting that ladder over the chrono and looking for a flat spot/velocity "node". That so-called "node" was then your target charge weight (well, picking a CW between the two that produced the seemingly flat spot).

I don't think the Satterlee method had anything specifically to do with testing seating depths. To my memory it was just a quick (and faulty) method for determining a velocity "node".

 

[Bbracken667]

The Satterlee method was loading up ~10 rounds of incrementally increasing charge weights, shooting that ladder over the chrono and looking for a flat spot/velocity "node". That so-called "node" was then your target charge weight (well, picking a CW between the two that produced the seemingly flat spot).

I don't think the Satterlee method had anything specifically to do with testing seating depths. To my memory it was just a quick (and faulty) method for determining a velocity "node".

Statistically this is almost completely random, result-wise. Loading 10 different charges is completely meaningless if you look at statistical requirements to get meaningful results.
This pretends that each round is exactly duplicate-able, that if you loaded another 10 that you would get the exact same results. Does that sound logical to you? Essentially the 2nd 10 would be hole in hole over the first 10, and the MV’s would also be the same. Not likely.
Frankly I find more of a repeatable process using the OBT method and I have zero clue what the math involved is. I do know it is consistent (the math)

 

[Dstoenner]

Statistically this is almost completely random, result-wise. Loading 10 different charges is completely meaningless if you look at statistical requirements to get meaningful results.
This pretends that each round is exactly duplicate-able, that if you loaded another 10 that you would get the exact same results. Does that sound logical to you? Essentially the 2nd 10 would be hole in hole over the first 10, and the MV’s would also be the same. Not likely.
Frankly I find more of a repeatable process using the OBT method and I have zero clue what the math involved is. I do know it is consistent (the math)

Eric Cortina had a huge thread on here about his method. You would load 10 steps .2 gns apart but 4 at each step. You would first shot 1 of each step looking for a possible high pressure point. Then you go back and fire the 3 of each step recording average, ES and SD. With that you look for a node or nodes where SD flatens out and is a good value. You can then as a second test adjust seating depth to fine tune the load with 3 at each seating depth.

By doing at least 3 you have a little better confidence that you don’t have statistical flukes. When i did this method and then plugged in all the data i had gathered into GRT out popped an OBT that was within .1 gn of my chosen load.


Edit: Eric Cortine’s thread is on accurate shooter forum not here. Forgot where i was

 

[iceng]

Lots of info here, and i agree with lots of it. Some not so much. (Not saying you are wrong, just that i havnt tested every option).

My personal experience with nodes and OBT are.. it depends on barrel profile also. My current opinion is the barrel "stretches" slightly (varmint Al simulations support this) and that is whats "causing" or amplifying your nodes.

Ive also found that different bullets have different windows of nodes. Has anyone had a bullet which seems to have a window of 0.5 to 0.7gr, and it still works, where another bullet only has 0.2 or 0.4gr at most before its crap again ?
My theory on this is bullet bearing surface. Some bullets have longer bearing surfaces than others, and the longer ones have less tolerance, and a very short "powder window".

Not saying its fact, im saying ive found this over multiple barrels with powder we use in AU. No idea if it holds true anywhere else. I need a MUCH bigger sample set (cartridge, barrels, power and proj).

 

[CK1.0]

The issue with many/most of these dogmatic reloading methods/theories is that they suspend reality and physics. Some are nothing more than something that may or may not have worked, for one guy, one time.

So, your new tuner may have shrunk your group… but it just as likely could’ve had more to do with what you had for breakfast, or maybe the stars aligned just right and you just shot a better one than usual.

Placebo effect (disambiguation) - Wikipedia

en.m.wikipedia.org

 

[kthomas]

Statistically this is almost completely random, result-wise. Loading 10 different charges is completely meaningless if you look at statistical requirements to get meaningful results.
This pretends that each round is exactly duplicate-able, that if you loaded another 10 that you would get the exact same results. Does that sound logical to you? Essentially the 2nd 10 would be hole in hole over the first 10, and the MV’s would also be the same. Not likely.
Frankly I find more of a repeatable process using the OBT method and I have zero clue what the math involved is. I do know it is consistent (the math)

Agree on the Satterlee method. I'm obviously a huge critic of it.

I'm also very skeptical of OBT and tuners.

 

[918v]

Those of you arguing statistics are wrong.

 

[918v]

See my responses above, apparent changes in dispersion with seating depth are often related to small sample size testing. In cases where it is not, there are any number of small factors that it affects that could be equally responsible for changes seen on target.

In my case I have around 1100 rounds on a particular barrel and thats enough to say that if I go outside the optimum coal range the group size increases, triples even.

 

[Bbracken667]

Eric Cortina had a huge thread on here about his method. You would load 10 steps .2 gns apart but 4 at each step. You would first shot 1 of each step looking for a possible high pressure point. Then you go back and fire the 3 of each step recording average, ES and SD. With that you look for a node or nodes where SD flatens out and is a good value. You can then as a second test adjust seating depth to fine tune the load with 3 at each seating depth.

By doing at least 3 you have a little better confidence that you don’t have statistical flukes. When i did this method and then plugged in all the data i had gathered into GRT out popped an OBT that was within .1 gn of my chosen load.


Edit: Eric Cortine’s thread is on accurate shooter forum not here. Forgot where i was

Nice! I like Erik’s approach to most things. Hard to argue with success, although I feel he is likely not telling us everything. He has admitted a couple of times that, effectively, much of his load development is “seat of the pants” gut feel stuff. He is beyond me.
He does make a barrel tuner. Add that to what is the best, and first approach to precise shooting? A heavier thicker barrel, no? Do you get smaller groups with a suppressor or without? There is a ton of evidence that something is going on there, and I completely reject the notion that charge and seating depth make no difference whatsoever, just pick a charge and make it work. There are more complexities than that.
Another effect: to me it has always been a heavier larger caliber round is much more forgiving than a lighter smaller bullet. That, logically, fits in somewhere in the “recipe”.
I have begun loading rounds for a test. I probably won’t shoot them for a few weeks since we are still experiencing near 100° weather here in N Texas. I never shoot when sweat will be flowing off me in streams lol

 

[Bbracken667]

In my case I have around 1100 rounds on a particular barrel and thats enough to say that if I go outside the optimum coal range the group size increases, triples even.

And yet, Erik Cortina is adamant about not following the lands. Claims it is just plain stupid to do so. I shot a 30-06 for many many years before the internet and “following the lands” was Greek to me. Never heard of it, and my opportunities for learning were few other than a few books of which Hodgdon load manuals were the major part. I set my col to book and went from there, never deviating. In the 90’s(?) when they were sending cd’s to your house for AOL etc they became my target of choice and with the same rifle I shot in the 70’s I could still hit one at 300 yds. Those days were very different than today. I never heard of barrel tuning, barrel harmonics or any of that until the 21st century. There is so much more data and information available these days it is mind blowing to an old fart like myself. I think there is something to GRT and the whole OBT thing, but I will have to do a lot of testing to convince myself. If nothing else it is a great simulation program I can use in place of QL

 

[918v]

I’m not saying I chase lands.

 

[secondofangle2]

Only thing I chase is tail.

Oftentimes my own, esp when reloading

 

[Thump_rrr]

I think much of the confusion people experience resulting in the complete lack of load development is the absolute lack of reliability regarding statistical analysis when one is only looking at 3 shot or 5 shot groups when 35 should be an absolute minimum to produce reliable data.
I like the concept of OBT and will answer the question for me, but I believe it will be months before I am satisfied one way or another. I am going with the long game here and will only draw conclusions when there is sufficient data to make a decision.
Anything else is voodoo science or religion (I believe)

You may not find what is definitively precise with a 3 or 5 shot group but even 2 shots will tell you what is not precise.

 

[Bbracken667]

You may not find what is definitively precise with a 3 or 5 shot group but even 2 shots will tell you what is not precise.

Statistically that is bunk. If you flip a coin 4 times how often will you get 2 tails and 2 heads? If you flip a coin 10 times, how often will you get 5/5? The more times you flip, the more the results will be statistically significant.

 

[Thump_rrr]

Statistically that is bunk. If you flip a coin 4 times how often will you get 2 tails and 2 heads? If you flip a coin 10 times, how often will you get 5/5? The more times you flip, the more the results will be statistically significant.

Here are the targets of my initial load deveopment for my Savage 110 BA in 338LM.



I purchased 110 rounds of factory Lapua 250gr ammo for the price of the brass alone.
Someone I met had nearly 2,000 rounds of the stuff and it didn't shoot well in his rifles either.
He was trying to recoup some of the cost.

I shot 40 rounds of the factory ammo before giving up and pulling the components.
At 300M it looked like a shotgun with 4"-8" "groups"
I will bet my bottom dollar that there is no way to improve that first group whether you shoot another 10 or 100 rounds.
Can any of those other groups open up to equal or surpass that first group with an additional 32 shots, Yes but you sure as hell cannot shrink that first group.

If you tell me that you would continue to fire another 32 rounds after those initial 3 then there is nothing more worth discussing because to me no matter where that group goes from there is unacceptable.

 

[secondofangle2]

no doubt some combinations work better than others in one barrel vs another.

The question is whether nodes, ladders, OBTs, ScatterLee, etc can reliably and consistently predict what's going to shoot in what

 

[Bbracken667]

Here are the targets of my initial load deveopment for my Savage 110 BA in 338LM.



I purchased 110 rounds of factory Lapua 250gr ammo for the price of the brass alone.
Someone I met had nearly 2,000 rounds of the stuff and it didn't shoot well in his rifles either.
He was trying to recoup some of the cost.

I shot 40 rounds of the factory ammo before giving up and pulling the components.
At 300M it looked like a shotgun with 4"-8" "groups"
I will bet my bottom dollar that there is no way to improve that first group whether you shoot another 10 or 100 rounds.
Can any of those other groups open up to equal or surpass that first group with an additional 32 shots, Yes but you sure as hell cannot shrink that first group.

If you tell me that you would continue to fire another 32 rounds after those initial 3 then there is nothing more worth discussing because to me no matter where that group goes from there is unacceptable.

This is an extreme example. I was referring to a normal load development where one is using expected candidates. I have fired one round that was hot, blew out the primer and was very hard to open the bolt. That only took one round but I am not talking about extreme situations.
Sorry for your experience with the ammo, it has happened to me before and no, I would not shoot another 32 rounds. Nor would I drive a car with 4 bald tires, nor a plane that had not been checked out in a year.
How often has that happened to you? 20 times? 50? Probably just once or twice. I have been shooting since the 70’s and have not had that experience but once.

 

[Bbracken667]

The issue with many/most of these dogmatic reloading methods/theories is that they suspend reality and physics. Some are nothing more than something that may or may not have worked, for one guy, one time.

So, your new tuner may have shrunk your group… but it just as likely could’ve had more to do with what you had for breakfast, or maybe the stars aligned just right and you just shot a better one than usual.

Placebo effect (disambiguation) - Wikipedia

en.m.wikipedia.org

The question would be if the results would be repeatable. That is what I require to establish veracity. If xyz combination of materials and measurements results in .334 moa then before I declare that to be my chosen result I will verify twice more on different trips to the range.
In the case of a tuner and a known load it should be easy to verify, or not as the case may be.
A lot of people only accept results (or won’t accept) providing they support their preconceived belief system. The placebo effect can work both ways, in a sense.

 

[CK1.0]

Here are the targets of my initial load deveopment for my Savage 110 BA in 338LM.



I purchased 110 rounds of factory Lapua 250gr ammo for the price of the brass alone.
Someone I met had nearly 2,000 rounds of the stuff and it didn't shoot well in his rifles either.
He was trying to recoup some of the cost.

I shot 40 rounds of the factory ammo before giving up and pulling the components.
At 300M it looked like a shotgun with 4"-8" "groups"
I will bet my bottom dollar that there is no way to improve that first group whether you shoot another 10 or 100 rounds.
Can any of those other groups open up to equal or surpass that first group with an additional 32 shots, Yes but you sure as hell cannot shrink that first group.

If you tell me that you would continue to fire another 32 rounds after those initial 3 then there is nothing more worth discussing because to me no matter where that group goes from there is unacceptable.

Wait. Buying $$$ .338 Lapua for a Savage is crazy.

If you're going to insist on shooting .338LM, stop disrespecting the Hide, throw that abomination in the nearest lake, and get an AI or MRAD with a RAPTAR on it. Geez.

 

[Thump_rrr]

This is an extreme example. I was referring to a normal load development where one is using expected candidates. I have fired one round that was hot, blew out the primer and was very hard to open the bolt. That only took one round but I am not talking about extreme situations.
Sorry for your experience with the ammo, it has happened to me before and no, I would not shoot another 32 rounds. Nor would I drive a car with 4 bald tires, nor a plane that had not been checked out in a year.
How often has that happened to you? 20 times? 50? Probably just once or twice. I have been shooting since the 70’s and have not had that experience but once.

It has happened to me a few times but I don't have 50 years of reloading experience.
I recently built a 6mm BR with a 1-10" twist and have started initial load development.
If I look at the suggested nodes and half nodes of GRT they seem to line up with my smaller groups but again my groups are of a small sample size.
GRT suggested nodes.
Node 3 32.99gr
Node 3-1/2 31.98gr
Node 4 31.5gr
Node 4-1/2 30.67gr

 

[CK1.0]

The question would be if the results would be repeatable. That is what I require to establish veracity. If xyz combination of materials and measurements results in .334 moa then before I declare that to be my chosen result I will verify twice more on different trips to the range.
In the case of a tuner and a known load it should be easy to verify, or not as the case may be.
A lot of people only accept results (or won’t accept) providing they support their preconceived belief system. The placebo effect can work both ways, in a sense.

If what you're after is an "xyz combination of materials and measurements", a "magic recipe" if you will... you will find it (see "Rorschach Test" earlier in the thread).

On any given day half the benches at my club have asses in them trying to find that magic recipe.

Obviously, some components work better than others, but I don't think it's about the magic recipe at all. I think if I could make the same exact round over and over, and if the shooter is good enough, they might all go through the same hole.

 

[Bbracken667]

It has happened to me a few times but I don't have 50 years of reloading experience.
I recently built a 6mm BR with a 1-10" twist and have started initial load development.
If I look at the suggested nodes and half nodes of GRT they seem to line up with my smaller groups but again my groups are of a small sample size.
GRT suggested nodes.
Node 3 32.99gr
Node 3-1/2 31.98gr
Node 4 31.5gr
Node 4-1/2 30.67gr

So, if you take the same loads, load them up again you will get exactly the same results?
If so, awesome. Statistically it is highly unlikely. That isn’t me saying that. There are many things to take into consideration but given the seemingly randomness of results at times 3 is just not enough. Nor is 5. One may decrease sample size by running multiple samplings of 3 or 5 in order to duplicate or verify results, but 2 runs are still not enough. I have fair confidence in GRT but I will be running more than a few tests. That is just to satisfy me that GRT works/doesn’t work.
Btw: ammo manufacturers like Hornady use sample sizes of over 100

How to choose a sample size (for the statistically challenged) - tools4dev

One of the most common questions I get asked by people doing surveys in international development is “how big should my sample size be?”. While there are many sample size calculators and statistical guides available, those who never did statistics at university (or have forgotten it all) may...

tools4dev.org

 

[secondofangle2]

Wait. Buying $$$ .338 Lapua for a Savage is crazy.

If you're going to insist on shooting .338LM, stop disrespecting the Hide, throw that abomination in the nearest lake, and get an AI or MRAD with a RAPTAR on it. Geez.

snipershide everything but their money

 

[secondofangle2]

It has happened to me a few times but I don't have 50 years of reloading experience.
I recently built a 6mm BR with a 1-10" twist and have started initial load development.
If I look at the suggested nodes and half nodes of GRT they seem to line up with my smaller groups but again my groups are of a small sample size.
GRT suggested nodes.
Node 3 32.99gr
Node 3-1/2 31.98gr
Node 4 31.5gr
Node 4-1/2 30.67gr

when there are nodes everywhere, they're not nodes

 

[Thump_rrr]

when there are nodes everywhere, they're not nodes

velocity vs grains of powder isn't helpful either.
No real flat spots.

 

[Thump_rrr]

snipershide everything but their money

Do you have your heart medication close by?
I love my Savages.

 

[secondofangle2]

My heart's fine. But I have Woodford

 

[Thump_rrr]

My heart's fine. But I have Woodford

I have a Weller Special Resere I picked up at Buffalo Trace in Frankfort Ky last month.

 

[brianf]

velocity vs grains of powder isn't helpful either.
No real flat spots.

People who believe in actual repeatable large flat spots believe in Bigfoot.

Go tell a physicist, actual engineer or mathematician that adding more propellant will not increase pressure hence velocity.

Reloading and it’s 50 years of here-say is the only task that is not bound by reality.

It hurts the brain.

 

[Thump_rrr]

Wait. Buying $$$ .338 Lapua for a Savage is crazy.

If you're going to insist on shooting .338LM, stop disrespecting the Hide, throw that abomination in the nearest lake, and get an AI or MRAD with a RAPTAR on it. Geez.

I may have quoted the wrong person earlier.
What I love about Savage is that I don't need a gunsmith to replace barrels.
I have gotten some great deals on some of these rifles
I got the 338LM for $1200 Canadian or around $900 USD.
It had 10 rounds through it and the seller gave me the other half of the box of 20 285gr ELD-M.
Thats how I knew that it would shoot 285's well.

I built my first custom rifle this year on an Ultimatum Deadline Gen 2 action and it's a great shooting rifle.
It is expected to shoot well.
People ae really surprised when you outshoot them with a rifle costing a fraction of what their rifle costs.
These are some of my Savages.
PS: They are all dead nuts reliable with no failures to feed, fire, extract, or eject.

 

[Thump_rrr]

People who believe in actual repeatable large flat spots believe in Bigfoot.

Go tell a physicist, actual engineer or mathematician that adding more propellant will not increase pressure hence velocity.

Reloading and it’s 50 years of here-say is the only task that is not bound by reality.

It hurts the brain.

So what do you look for when looking for a node?
Small groups next to each other?
Little to no POI shift?
Not a flat spot in velocity obviously.
Believing in Bigfoot is just stupid. Chupacabra's on the other hand.....

 

[brianf]

So what do you look for when looking for a node?
Small groups next to each other?
Little to no POI shift?
Not a flat spot in velocity obviously.
Believing in Bigfoot is just stupid. Chupacabra's on the other hand.....

From reputable sources..I’ll keep names out if it

Pick a velocity
Adjust seating depth
Go shoot

The idea isn’t to always hot rod ammo

Get the bullet and cartridge to work in their design pentameters and magically it shoots well.

Guys who are always saying they are 2gr over the max in the book etc..your over pressure plain and simple

Want better ballistics get a better cartridge

 

[secondofangle2]

People who believe in actual repeatable large flat spots believe in Bigfoot.

Go tell a physicist, actual engineer or mathematician that adding more propellant will not increase pressure hence velocity.

Reloading and it’s 50 years of here-say is the only task that is not bound by reality.

It hurts the brain.

Yes. The only thing I look for in flat spots and nodes is pure randomness. And I see it every time I look at them.

 

[secondofangle2]

The other thing that is being overlooked here is the fact that cartridges were not designed in an isolated vacuum, completely independently of available bullets, powders and primers. As if God made the 300 Norma magnum and left it to you to figure out what powder and bullet works best with that, if anything works at all.

If some company or relatively sophisticated developer brings to market a cartridge for the public to consume in mass, he has probably tested it using mostly available powders, projectiles, and primers. (Or in the case of 375 Cheytac, has commissioned a manufacturer like Sierra to make the 350 SMK specifically for that new cartridge.) He already knows that it works for certain combinations because he has probably tested it ad nauseam with, say, a 140 grain bullet and H4350.

If you have a 308 that happens to shoot well with “your” special load of 4895, 4064, VARGET, or RL15, you are either some kind of genius that found a “node“ or you stumbled across what some team of engineers already developed the entire cartridge around using hundreds of thousands of rounds.

Call it a “node“ if you want. You might as well call it a “known“

 

[Thump_rrr]

The other thing that is being overlooked here is the fact that cartridges were not designed in an isolated vacuum, completely independently of available bullets, powders and primers. As if God made the 300 Norma magnum and left it to you to figure out what powder and bullet works best with that, if anything works at all.

If some company or relatively sophisticated developer brings to market a cartridge for the public to consume in mass, he has probably tested it using mostly available powders, projectiles, and primers. (Or in the case of 375 Cheytac, has commissioned a manufacturer like Sierra to make the 350 SMK specifically for that new cartridge.) He already knows that it works for certain combinations because he has probably tested it ad nausea him with, say, a 140 grain bullet and H4350.

If you have a 308 that happens to shoot well with “your” special load of 4895, 4064, or RL15, you are either some kind of genius that found a “node“ or you stumbled across what some team of engineers already developed the entire cartridge around using hundreds of thousands of rounds.

Call it a “node“ if you want. You might as well call it a “known“

I agree with your going with known good components.
I always use Lapua brass in all my bolt action centerfire rifles.
I actually also use Lapua/SK in my rimfire CZ rifes.
H4350 for 6.5 Creedmoor, Varget for 6mm BR and 308 in bolt actions and IMR 4064 for M1A's and M1 Garands.
As far as bullets I used to buy mainly Sierra but now it's mostly Hornady and Lapua

CCI BR-2 amd BR-4 for primers.

 

[iceng]

Do you have your heart medication close by?
I love my Savages.

Just because you are gay, doesnt mean its natural,.. or right.

 

[Dstoenner]

It was asked “what do you look for?” When i run the 10 loads at .2 gn using at least 3 rounds per step, i use the criteria of the best group that has a low ES of less than 20 fps, a SD of around 5 but a single digit and that at least on neighboring group is similar. If I don’t see this i don’t think it is a real node or it is and WAY too narrow and either try to higher if I didn’t hit high pressure or switch powder and try again.

By the way, Brian litz’s latest book on Advanced Long Range topics has a big section on statistics and load development. It is mind bending and does pull the rug out from underneath us.

 

[Bbracken667]

snipershide everything but their money

I like your nickname. Second of angle is awesome!

 

[CK1.0]

There's no such thing as a "node".

Santa isn't real either.

Get over it.