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

[Dthomas3523]

Node defined as a velocity flat spot is BS, maybe you get one most likely you will not.
And if you do get one 99% of the time you shoot the test again you will get different results.
I simply look for point of impact consistency for a range of consecutive charge weights that produce the velocity I am looking for.

If I can get say a charge of 41.1g to 41.5gr to group in the same spot that is my load. I will pick 41.4 and 41.3 and play with the
seating depth.

The chart you posted, if you are just picking out of a hat then why not just pick the highest velocity with lowest SD and your done.
Will the random load you picked give you consistency?

and @Campguy308

I can take every charge weight out of that charge, toss a berger bullet on top with about .020 jump, dope the rifle and not miss a practical size target out to 1k because of vertical.

I can then take that BC or curve pretty much anywhere, check the velocity, input it into software and it will still hit every practical size target.

 

[Campguy308]

and @Campguy308

I can take every charge weight out of that charge, toss a berger bullet on top with about .020 jump, dope the rifle and not miss a practical size target out to 1k because of vertical.

I can then take that BC or curve pretty much anywhere, check the velocity, input it into software and it will still hit every practical size target.

So you'd take the chance of picking a 1 MOA load over a 3/8 MOA load?
What do you consider a practical size target? 1 MOA?

I'm not necessarily disagreeing here, as I appreciate the insight. I've had rifles that shot like hell at say 43 grains, and tightened up at 45.

 

[John Glidewell]

I’ve found as long as I keep the powder drop and neck tension consistent, it’s pretty hard to have shitty chrono numbers.

This right here. What I tell folks, 2 most important things, neck tension and powder drop.

 

[Dthomas3523]

So you'd take the chance of picking a 1 MOA load over a 3/8 MOA load?
What do you consider a practical size target? 1 MOA?

I'm not necessarily disagreeing here, as I appreciate the insight. I've had rifles that shot like hell at say 43 grains, and tightened up at 45.

You could make that 43 shoot just as good as 45 with seating depth.

It’s pretty hard for a rifle not to shoot .5-.75 nowadays.

I’m not saying I wouldn’t tweak my seating depth to get it tighter. What I’m saying is I’m not going to sit around making 2 range trips in an attempt to dial in some powder based on group shooting when I can load anything I want and either be fine or adjust the seating slightly.

For what it’s worth, I run an EC tuner now. So I just load the charge weight I want, load .020 or so off lands, shoot a few groups to adjust tuner and I’m done.

Here’s dasher last week without anything except a couple minutes of adjusting tuner (seating depth would do the same).

I didn’t shoot more than one as this bullet is known quantity for me. Been using it a year. It hit watermark from 300-1100. Haven’t needed to shoot groups with it for confirmation in a while.

 

[Precision Underground]

You could make that 43 shoot just as good as 45 with seating depth.

It’s pretty hard for a rifle not to shoot .5-.75 nowadays.

I’m not saying I wouldn’t tweak my seating depth to get it tighter. What I’m saying is I’m not going to sit around making 2 range trips in an attempt to dial in some powder based on group shooting when I can load anything I want and either be fine or adjust the seating slightly.

For what it’s worth, I run an EC tuner now. So I just load the charge weight I want, load .020 or so off lands, shoot a few groups to adjust tuner and I’m done.

Here’s dasher last week without anything except a couple minutes of adjusting tuner (seating depth would do the same).

I didn’t shoot more than one as this bullet is known quantity for me. Been using it a year. It hit watermark from 300-1100. Haven’t needed to shoot groups with it for confirmation in a while.

Using a tuner is the same thing as doing an OCW test but your changing the barrel harmonics to match the load rather than the other way around. You can’t shoot a bolt gun with truck axel 6mm barrel and a tuner while telling me that I’m wasting my time doing an OCW on a precision AR lol.

Have you loaded for a lot of different calibers and barrel profiles or mainly for PRS type rifles?

 

[Secant]

What is the weight of an EC Tuner (or similar) and what is the typical longitudinal adjustment length differential that guys are seeing between a “good” setting to a “bad” setting?

 

[Campguy308]

What is the weight of an EC Tuner (or similar) and what is the typical longitudinal adjustment length differential that guys are seeing between a “good” setting to a “bad” setting?

Erik Cortina has a video showing this adjustment vs grouping I believe.

 

[Secant]

Erik Cortina has a video showing this adjustment vs grouping I believe.

I’ve seen some of the videos. I was thinking of running some back of the envelope numbers behind the mechanics. Just looking for some decent inputs to use.

 

[Macht]

I think something that clouds this issue is that "node" is not clearly defined. For some reason there is a strong misconception that barrels vibrate in a neat sinusoid and the handloader is trying to find either a peak or a trough. The truth is that the forced response of the system is equal to or greater than the harmonic response and almost no sinusoidal behavior is seen near projectile exit, especially in heavier barrels.

 

[Precision Underground]

I think something that clouds this issue is that "node" is not clearly defined. For some reason there is a strong misconception that barrels vibrate in a neat sinusoid and the handloader is trying to find either a peak or a trough. The truth is that the forced response of the system is equal to or greater than the harmonic response and almost no sinusoidal behavior is seen near projectile exit, especially in heavier barrels.

I think it makes it easier to think about if we picture the “wave” in the barrel and timing the shot to exit at the optimal time. In (my)reality it’s a vibration like in a bell that has been rung. Vibrations are waves even if you can’t see them. If you tap a bell it rings to confirm there are vibrations whether you can see them or not. I have no data to prove exactly what is physically happening but POI shifts through charge weights are real and are repeatable and that’s the best I can make it make sense in my head.

 

[Clint E.]

I’ve found neck tension is probably the most important thing...with up to(and possibly more).6g powder variation I have a 35fps ES which is 5fps over what I normally like to see as a high but loading on the 750 is so fast and easy I’ll deal with the ES until I see a problem.

What is your process for achieving the consistent neck tension ? Mandrel ? Annealing ?

 

[Macht]

I think it makes it easier to think about if we picture the “wave” in the barrel and timing the shot to exit at the optimal time. In (my)reality it’s a vibration like in a bell that has been rung. Vibrations are waves even if you can’t see them. If you tap a bell it rings to confirm there are vibrations whether you can see them or not. I have no data to prove exactly what is physically happening but POI shifts through charge weights are real and are repeatable and that’s the best I can make it make sense in my head.

Clearly there are vibrations in the barrel. My point is that the forced response somewhat overpowers the induced harmonic response. POI does shift with charge weight, that doesn't mean the dominant movement of the barrel during firing is a clean sinusoid. "Picturing the wave" has limited basis in reality.

 

[Precision Underground]

Clearly there are vibrations in the barrel. My point is that the forced response somewhat overpowers the induced harmonic response. POI does shift with charge weight, that doesn't mean the dominant movement of the barrel during firing is a clean sinusoid. "Picturing the wave" has limited basis in reality.

What are you calling forced response? The rifle moving when fired?

 

[47guy]

What is your process for achieving the consistent neck tension ? Mandrel ? Annealing ?

i anneal every time and do not size until i load so station 1 is a full length bushing die station 2 is a mandrel.

i should add to this that i used a FL bushing die with the expander ball for years i just started using the mandrel again(which i used in the past)because im running the progressive press and am pulling the handle anyway.

 

[47guy]

This right here. What I tell folks, 2 most important things, neck tension and powder drop.

you and i have talked about this a few times...i agree powder is important but if your shooting across a so called node with a .1g difference in charge weight to tune a load then that is not a good load because environmentals will cause your load to fall apart...even .2g is to close IMO....the last match we shot i should have won but got bad calls on 2 rabbits and im 99% sure one coyote and again that ammo was loaded on the 750.

 

[Campguy308]

i anneal every time and do not size until i load so station 1 is a full length bushing die station 2 is a mandrel.

Are you lubing inside of necks for mandrel? If so how are you cleaning that out on the progressive?

 

[47guy]

Are you lubing inside of necks for mandrel? If so how are you cleaning that out on the progressive?

i anneal then when cases cool i trim(ive figured out where i need to be with a fired case to have the trim length i want when sized)i have a brush in a lyman case prep center and brush the necks right after annealing....when im ready to load i spray with one shot then stand the cases up and spray the inside necks with a light shot of 1 shot...ive been using one shot inside cases necks for a long time.

 

[Campguy308]

i anneal then when cases cool i trim(ive figured out where i need to be with a fired case to have the trim length i want when sized)i have a brush in a lyman case prep center and brush the necks right after annealing....when im ready to load i spray with one shot then stand the cases up and spray the inside necks with a light shot of 1 shot...ive been using one shot inside cases necks for a long time.

And just leave it in there?

 

[47guy]

And just leave it in there?

yes...it does not hurt bother or change anything...keep in mind its not dripping wet its a light spray and free of moisture(dries)quickly.

 

[morganlamprecht]

Lol at the guys here that listened to the recent interviews and are now 100% against load work up and acting like they don’t understand what us simpletons are looking for when doing it.

My definition of a node is a similar (mainly vertical) POI for a range of charges. Being in a node avoids landing on the edge of a POI shift. It has nothing to do with speed or numbers. Here’s another example.
View attachment 7450858
I’d feel good about 45 on this target. Both sides of it show consistent vertical spread. But what if I randomly chose 45.5with no test? I would land on the edge of that POI shift down. Would it matter? I don’t know I’ve never attempted to land on the edge of a node. Could you tune it with seating depth? I don’t know. But POI shifts through different charge weights are real. Maybe it matters maybe it doesn’t. But considering how easy it is to test and avoid there’s no reason not to do it. You’re going to need to find your max load and check speed anyway. Just use that progression of rounds to check POI on the charges.
And again, when you’re shooting a straight taper Brux barrel it prob isn’t going to shift much if at all. So if that’s what you’re loading for you very likely can just throw a random load in and go with it. When I work up a heavy, premium barrel everything lands pretty much in the same spot. Work up a .750 AR barrel and you may not have the same result.

some of us got here before any of the recent pod casts came out and have done multiple variations of all of these tests on multiple guns over months and 1000s of rounds...we've also had other people try to prove and repeat them...and we have more than just heavy barrel match guns

everyone finds something they like then moves forward...i dont know anyone who ever went back and tested the "bad" loads again, until i told them they should...they didnt see what they expected to see

just because something occurs one way in a string of 3 or 5 round shots, hell ive even seen 10 round strings retested and not repeat for a shooter...doesnt mean its gospel and going to happen the exact same every other time youd do it

 

[louu]

This thread made my brain hurt.

One simple question I want to ask...

Once you picked your charge weight, then you start playing with seating depth, wouldn't that change everything?

 

[47guy]

This thread made my brain hurt.

One simple question I want to ask...

Once you picked your charge weight, then you start playing with seating depth, wouldn't that change everything?

seating depth is to tune a load

 

[Conrad]

You could make that 43 shoot just as good as 45 with seating depth.

It’s pretty hard for a rifle not to shoot .5-.75 nowadays.

I’m not saying I wouldn’t tweak my seating depth to get it tighter. What I’m saying is I’m not going to sit around making 2 range trips in an attempt to dial in some powder based on group shooting when I can load anything I want and either be fine or adjust the seating slightly.

For what it’s worth, I run an EC tuner now. So I just load the charge weight I want, load .020 or so off lands, shoot a few groups to adjust tuner and I’m done.

Here’s dasher last week without anything except a couple minutes of adjusting tuner (seating depth would do the same).

I didn’t shoot more than one as this bullet is known quantity for me. Been using it a year. It hit watermark from 300-1100. Haven’t needed to shoot groups with it for confirmation in a while.

I completely understand what you mean by using excellent reloading equipment and components and easily getting a load.

You've mentioned a couple times you find your powder charge with a chrono, but I get the impression you’re not doing the Saterlee method? Can you explain how you’re choosing charge? Do you shoot enough rounds of multiple charges and pick the charge with the best SD? Or do you just find pressure, back off a bit to be say heat or rain safe, remeasure/shoot for average velocitY and then move on with your tuner?

Ive heard others say they just find the velocity they “want” to shoot and I’m trying to understand how do you determine that velocity?

Thanks.

 

[NamibHunter]

Well, the OP has defined a very narrow set of circumstances and then posed his question:

Assume 1 MOA steel targets. So there are no points for small groups or hitting the X mark. Shooting a 1/4 MOA rifle vs a half MOA rifle has little to no advantage here. [A WEZ analysis will bear that out.]

Targets are out to a max of maybe 1100 yards, usually less.

So PRS/NRL competitions shot from difficult positions where the shooter is most often the weak link in the accuracy chain, not the 20 lbs chassis rifle with premium barrel. Very heavy barrels usually.

He is asking “under these very specific conditions, can you be competitive in PRS/NRL with very limited load development and simply ignore nodes?” [An argument also made by Bryan Litz.]. Note he is skipping optimal charge weight but he is still optimizing seating depth and/or using his barrel tuner to get similar POI as speed varies.

Unfortunately, there is no univerally acceptable definition of a rifle “node”. Let’s assume it is the flat spot on the speed vs charge weight graph where speed is fairly flat and SD is often also smaller than elsewhere. [Not universally true that SD is small at the flat spot, and the flat spot could move around if the powder is temperature sensitive, or the barrel gets very hot.]

‘Positive compensation’ is often a follow-up step where seating depth and / or tuner settings are varied to get same/similar POI even if speed varies quite a bit. [Results are somewhat distant dependent, so what works perfectly at 200 is not exactly perfect at 1,200.].

Let’s assume that conventional load development is the combo of finding the flat spot/low SD powder weight AND tuning in positive compensation for the distances you care about.

I have to agree with the OP:

Personal experience is that my 20 lbs MPA comp rifle in 6.5 CM almost always shoots factory match ammo below 0.6 MOA at 100, even if SD is 10-13 fps and ES is as high as 35 fps. Yes vertical stringing is a bit problematic until i use the barrel tuner to achieve positive compensation. That’s why i got one: To shoot factory ammo well.

That MPA rifle shoots Hornady 140 ELD match and Berger 140 gn factory ammo below 0.4” at 100. Better than needed for the scenario defined by the OP.

The rifle has a tuner installed, so positive compensation can easily be dialed in at the bench. It has the same effect as tuning seating depth. So for me that is a replacement for full load development.

Hand loads (for a batch of 100) have SD of 5-9 fps and ES of 20-30 fps, and performs only slightly better than Berger factory ammo. Now i can hit the 3” target at 600 half the time or better, but only if i manage to read the wind changes correctly, which is not easy.

But: I also have a pencil barrel 7 lbs 30 cal hunting rifle,and if i shoot random factory ammo through it, the groups can be anywhere from 0.5” to 4” or worse at 100. For some strange reason it shoots 180 Barnes TTSX factory ammo into 0.25” groups. Same day, same rifle, same wind, same shooter. So of course I do a full load workup (FX120 scale, full brass prep, AMP annealed, optimize charge weight and optimize seating depth) for this rifle whenever i try a different hunting bullet. No choice here, because there is no barrel tuner installed, as i am trying to keep the rifle compact and light.

Those who shoot BR or F-class will probably always optimize their ammo to the n’th degree because there is a major competitive advantage to doing so. If you want to shoot groups in the ones, do a full load workup.

 

[John Glidewell]

you and i have talked about this a few times...i agree powder is important but if your shooting across a so called node with a .1g difference in charge weight to tune a load then that is not a good load because environmentals will cause your load to fall apart...even .2g is to close IMO....the last match we shot i should have won but got bad calls on 2 rabbits and im 99% sure one coyote and again that ammo was loaded on the 750.

Totally agree. I have learned so much over the last couple years. I went back and looked at all the data I have saved on various rifles and compared the data. (Data junkie with masters in statistical analysis) I have found that looking 2-3 grains back from pressure and shooting across the obt load lands a good result. It matches ocw and Saterlee results, very close. On this note, I have found, working with newer people, poor load processes lead to poor results and why they get frustrated and say it does not work. It is not the method, it is their process/equipment. Also, there are many ways to find a load, none are wrong, it is more about what works for each individual. My method is fast and works for me. Less time messing with load and more time shooting. On the match, I told you that is in part why I went to bigger caliber. Center punching a coyote at 850 that is already dirty, with a little 6mm, yeah those impacts get missed a Lot.

 

[kthomas]

I completely understand what you mean by using excellent reloading equipment and components and easily getting a load.

You've mentioned a couple times you find your powder charge with a chrono, but I get the impression you’re not doing the Saterlee method? Can you explain how you’re choosing charge? Do you shoot enough rounds of multiple charges and pick the charge with the best SD? Or do you just find pressure, back off a bit to be say heat or rain safe, remeasure/shoot for average velocitY and then move on with your tuner?

Ive heard others say they just find the velocity they “want” to shoot and I’m trying to understand how do you determine that velocity?

Thanks.

I won't speak for Dthomas, but I'll put my own 2¢ in.

First off, the "Satterlee method" is garbage, and is only useful for finding approximate velocity per charge weight and where pressure starts. But at that point, it's just a velocity ladder and not the "Satterlee method".

The velocity is pretty much contrived. You don't want to be too close to pressure, but beyond that it's a completely personal thing. There's no one best velocity. For a 6BRA or Dasher for example, you can have pretty much any velocity between 2800-2950 fps and still come up with a good shooting and low SD/ES round, as long as you are using quality components and reloading equipment.

When I do my load tests, I generally test ES/SD with 5 round groups, but I'm starting to find that that isn't necessarily enough data points to pick the "best" velocity, but I don't think there is one. All my reloads have an SD of ~3-5 over 10+ shots, it doesn't really matter what charge weight I pick. It's more a matter of consistency of powder drop.

Again, I can't speak for Dthomas and his method for choosing a velocity, but I think to his point is that it doesn't really matter. Some people may want a slower velocity to better see trace and reduce recoil, others may want to be closer to 2950 fps just because. There's no one right answer.

 

[Dthomas3523]

I completely understand what you mean by using excellent reloading equipment and components and easily getting a load.

You've mentioned a couple times you find your powder charge with a chrono, but I get the impression you’re not doing the Saterlee method? Can you explain how you’re choosing charge? Do you shoot enough rounds of multiple charges and pick the charge with the best SD? Or do you just find pressure, back off a bit to be say heat or rain safe, remeasure/shoot for average velocitY and then move on with your tuner?

Ive heard others say they just find the velocity they “want” to shoot and I’m trying to understand how do you determine that velocity?

Thanks.

Look into Erik Cortina videos. I use a variation of this method.

However as others have pointed out, it’s not of much consequence for the game most of us here play.

Take a look at the chart I’ve posted several times. If all of the charge weights are of acceptable sd/es for our intended purposes, and we either have acceptable accuracy or dial in our seating depth for acceptable accuracy, does it really matter which charge weight you used?

It’s become hard to load shitty ammo. You almost have to try.

 

[VVhoisJohnGalt]

First off...great thread! Thanks dthomas.

I will add my anecdotal data as well. For years I’ve just loaded for velocity and then adjust my seating depth to tighten up.Mostly hunting rifles with thin barrels and some Palma barrel profiles.
Started shooting PRS style matches last year and found the node “rabbit hole” after doing some actual research on reloading.
Running 6creed MTU I would use the first 100rnds to node test etc. through speed up. Then chase lands for next 1000rnds and start over on a new barrel. Did three barrels like this last year...too much work.
First MTU 6dasher barrel this year I just loaded for 2940 and waaay off lands around .120”. It shot fine around .5” ten shot strings. So I just ran it. Put 2450rnds on it and always around .5-.6”. Good enough for what we do.
Second barrel is doing the same.
I think I would agree that the reloading equipment now...if you go all in...just makes really good ammo.
And these Br based cartridges just seem too easy to load and shoot. I think node testing might make a difference on thinner barreled finicky hunting rifles if done right but on these heavy barreled Br based cartridges...it may be a waste of time.

 

[Doom]

Dthomas,

Let me say that you put some real thought into this thread and shared some interesting information (as have others). From a testing and physics standpoint I can't say that any of your assumptions or conclusions are unreasonable. If your table is correct, and I cannot find any reason that it shouldn't be doable, I believe your method will work.

I normally work up my loads based on Dan Newberry's OCW method and have loads that are less than a quarter of an inch at 100yds. I am about to work up another bullet for that rifle (52 Berger vs 53 SMK). The bullets are significantly different and I was questioning what COAL to use. I am going to put your theory to the test. Granted that this is not a PRS type caliber but if the theory is correct is shouldn't matter.

Most probably I will not chronograph the loads since I only have an optical chronograph and its a PITA to set up on our range.

 

[Conrad]

Look into Erik Cortina videos. I use a variation of this method.

However as others have pointed out, it’s not of much consequence for the game most of us here play.

Take a look at the chart I’ve posted several times. If all of the charge weights are of acceptable sd/es for our intended purposes, and we either have acceptable accuracy or dial in our seating depth for acceptable accuracy, does it really matter which charge weight you used?

It’s become hard to load shitty ammo. You almost have to try.

Last I checked Cortina is looking at similar POIs and picking the forgiving group in the middle of similar POIs Or vertical displacement.

I understand your message, just was curious how you land on a certain charge if you’re only looking at chrono data, but maybe you’re doing more than that. I didn’t gather that you were picking a charge off of group shooting.

Recoil, brass life, known velocity for a particular bullet according to other shooters, etc. is what I was anticipating as an answer.

 

[Secant]

Disclaimer: I’m bouncing between work & this post and I'm working a bit off of memory, so hopefully somebody will double check me here:

Looks like the ATS tuner is 6oz total. Is it fair to say the moving weight is +/-3oz? The CST tuner has a total linear adjustment range of 0.4”, with 0.001" gradation. These are some rough baselines that I am using for a basic comparison.

------------------------------------------------------------------

Some extremely rough back of the envelope calcs for a few barrel contours are as follows:

A 26", 0.264 caliber straight taper #8(ish) barrel will have an area moment of inertia very roughly in the +/- 0.00371 in^4 realm (not integrating, just a relative average). The slenderness ratio will be very roughly +/- 190.

A 26", 0.264 caliber medium palma barrel will have an area moment of inertia very roughly in the +/- 0.00171 in^4 realm (approximately one half of the #8 barrel listed above). The slenderness ratio will be very roughly +/- 230 (approximately 20% more than the #8)

A 26", 0.264 caliber #5 taper(ish) will have an area moment of inertia very roughly in the +/- 0.00124 in^4 realm (approximately one-third of the #8 barrel listed above, and approximately three quarters of the medium palma barrel). The slenderness ratio will be very roughly +/- 245 (approximately 30% more than the #8 and approximately 5% more than the medium palma)

Obviously, there are a large amount of combinations in terms of contours, lengths & calibers. Additionally, different manufactures are using different steel and manufacturers also receive different lots of steel through time. These different steels all will all have a different modulus of elasticity, but will be similar from a 10,000 ft view.

-------------------------------------------------------------------------------------------------

Going back to the tuner weight & adjustment lengths, I think it's fair to say that a suppressor cover is about the same weight as the moving weight on a tuner. Now the suppressor itself may act somewhat as a dampener; however, if a tuner works as advertised, moving a suppressor cover back by 0.5" or 1" from the end would have an analogous effect on your barrels "harmonics". Similarly, a lighter contour barrel (say the #5 listed above) may notice similar effects between a bare muzzle with a thread protector on vs. off as a #8 contour may experience with a tuner adjustment. How many people can say they've noticed an effect in precision and/or accuracy by moving their suppressor cover/wrap (not related to mirage) or by simply removing a muzzle thread protector?

Looking at the Hornady Load Data pdf for 147 ELDM (just a random example), the difference in about 1-grain correlates to about 50-fps and recoil impulse difference of about 0.05 lb-sec (or about 2% difference). If rifle weight is a constant, the difference in the 1-grain charge weight (and associated velocity difference) will result in a recoil velocity difference of +/-2% and a difference in recoil energy of +/-4%. So the relative difference in recoil impulse & velocity with 0.2 grain charge weight increase/decrease would obviously be far less than 2% (likely in the sub 0.5% range), and the recoil energy would likely be less than 1% for the 0.2 grain charge weight increase/decrease..

When we’re evaluating dynamics, we’re looking at geometry, material properties, and ‘loading’ (to over simplify). So why don’t we see much larger variations in charge weights to get the proper “node” when we have similar material properties and fairly large swings in geometry between contours/lengths?

It seems like whether a dude has a 24” M24 or a 26” medium Palma or [fill in the blank], the load for a 6 dasher or 6.5 CM or 308 or [fill in the blank] is within a grain or less (or sometimes exactly equal), and that 20 thou off the lands works for a large number of match bullets. What is the explanation for the lack of variability in charge weight and seating depths when we have substantial variations in barrel geometry (contours & lengths) and material properties remain the same/similar?

 

[morganlamprecht]

Last I checked Cortina is looking at similar POIs and picking the forgiving group in the middle of similar POIs Or vertical displacement.

I understand your message, just was curious how you land on a certain charge if you’re only looking at chrono data, but maybe you’re doing more than that. I didn’t gather that you were picking a charge off of group shooting.

Recoil, brass life, known velocity for a particular bullet according to other shooters, etc. is what I was anticipating as an answer.

for matches i just run 6mm 105-110s 2950-3050 in 24-26" barrels

6.5 130s 2850-2900 and 140s 2750-2800 also in 24-26" barrels

in the standard case sizes i run those function easily always and get the ballistics where id expect them to run...i dont run any smaller BR variant cases

ive gotten there with rl16, varget, h4350, h4831, and h1000...makes no difference to me

in my current 2 hunting rifles, both ~9lbs w/ can...22" #3b 6.5prc and 26" #3 280prc (300 necked down), i wanted a 140ish going 3000-3100 and a 175-180 going 3100-3200...currently running a 135 classic hunter @ 3055 and a 175 elite hunter @ 3150...both will wear out a 6" paint dot @ 800 yds

 

[47guy]

Totally agree. I have learned so much over the last couple years. I went back and looked at all the data I have saved on various rifles and compared the data. (Data junkie with masters in statistical analysis) I have found that looking 2-3 grains back from pressure and shooting across the obt load lands a good result. It matches ocw and Saterlee results, very close. On this note, I have found, working with newer people, poor load processes lead to poor results and why they get frustrated and say it does not work. It is not the method, it is their process/equipment. Also, there are many ways to find a load, none are wrong, it is more about what works for each individual. My method is fast and works for me. Less time messing with load and more time shooting. On the match, I told you that is in part why I went to bigger caliber. Center punching a coyote at 850 that is already dirty, with a little 6mm, yeah those impacts get missed a Lot.

there is no doubt when a 109 hits a rabbit it was bad calls or communication from spotter to score guy...not a big deal i still got my 50c ribbon lol

 

[BLKWLFK9]

Yall just need to listen to my 1st episode I recorded with Erik Cortina and call it a day.

 

[BLKWLFK9]

Episode 25: Team USA F-Class Shooter ERIK CORTINA

I told yall I was going to deliver, and what I delivered was 3 hours of knowledge coming straight to your ear holes. Erik was an absolute pleasure to have on. I learned so much and left me wanting to learn more. 3 hours just wasn't enough. Erik will be making at LEAST one more appearance on...

www.podbean.com

 

[Dthomas3523]

Last I checked Cortina is looking at similar POIs and picking the forgiving group in the middle of similar POIs Or vertical displacement.

I understand your message, just was curious how you land on a certain charge if you’re only looking at chrono data, but maybe you’re doing more than that. I didn’t gather that you were picking a charge off of group shooting.

Recoil, brass life, known velocity for a particular bullet according to other shooters, etc. is what I was anticipating as an answer.

Cortina fires rounds into a berm with chrono to find powder charge weight. His post on accurate shooter is old and not the current process.

 

[Dthomas3523]

Last I checked Cortina is looking at similar POIs and picking the forgiving group in the middle of similar POIs Or vertical displacement.

I understand your message, just was curious how you land on a certain charge if you’re only looking at chrono data, but maybe you’re doing more than that. I didn’t gather that you were picking a charge off of group shooting.

Recoil, brass life, known velocity for a particular bullet according to other shooters, etc. is what I was anticipating as an answer.

There is a second part to his method where once he has found the charge and seating depth, he will shoot charges in .1 increments on each side and look at the group dispersion.

But this is a final step and only in a very small window.

For PRS, this is likely dialing in a bit more than we need. But it won’t hurt.

 

[Precision Underground]

some of us got here before any of the recent pod casts came out and have done multiple variations of all of these tests on multiple guns over months and 1000s of rounds...we've also had other people try to prove and repeat them...and we have more than just heavy barrel match guns

everyone finds something they like then moves forward...i dont know anyone who ever went back and tested the "bad" loads again, until i told them they should...they didnt see what they expected to see

just because something occurs one way in a string of 3 or 5 round shots, hell ive even seen 10 round strings retested and not repeat for a shooter...doesnt mean its gospel and going to happen the exact same every other time youd do it

My point is that guys who are suddenly experts on how people are wasting time doing OCW tests were on here talking about their own OCW tests and helping guys read their OCW tests a short time ago. Now some new info is out there and suddenly they have no idea what anyone would be looking for in an OCW or why they would want to do something so futile. I get that there’s a new school of thought and maybe it works great but that doesn’t make OCW invalid. You notice the prerequisite for the new line of thinking is you have to have absolutely exact powder charges and preferably buy enough of a lot of powder to last the whole barrel. That sounds like a good way to avoid a POI shift should you pick a random charge that’s on the edge of a POI shift. I’m fine with those “from a time before” loads that can go .1 and usually .2 or more up or down and still shoot the same.

I’ll agree that a lot of guys can’t shoot good enough and spend 4 range trips running OCWs and their targets are a mess that show nothing. This is apparent in a lot of the OCW targets that get posted here. But an OCW shot correctly has pretty much always shown me where I should be via POI in about 35 rounds. I’ve loaded for everything from a light weight hunting rifle to large and small frames to heavy barreled magnums. I always end up with good loads that hold up.

Let’s say maybe it’s not the POI data that matters. What have I lost? I got a good load and I would have shot the 35 rounds that were used in the OCW to find max charge and get velocity data anyway. Why not do it? Does it really make more sense to just pick a random charge? What are you gaining by doing that? My consequence for being wrong about OCW being useful is that there are no consequences. I shot 35 rounds that I would have shot anyway. The consequence for using a random charge(if you happen to land on the very edge of a shift and something changes) could be an unexplained POI shift that will make your tail irresistible to chase for an unknown amount of time. I don’t see the reason not to do an OCW if you can shoot good enough to read/believe the target. I just don’t see the huge benefit that’s being implied or how it’s so much better.

Obviously you can just pick a charge if you’re using a barrel tuner because you can change your harmonics via the tuner rather than the charge weight. But using a barrel tuner while also saying OCW is pointless makes no sense to me. That’s basically taking the position that a different charge weight won’t change the frequency/velocity of the harmonic waves in the the barrel. I’m no physicist but I’d imagine a different size explosion would create different harmonic waves in the barrel. If thats the case that means OCW tests are valid. And again- heavy, inherently accurate barrels are not good test subject to gather data on this because they will be affected much less by small changes in charge weight; especially in small calibers.

for the last 3-4 yrs ive ran all my load work up off 100 yd ocw, then i chrono...ive never had a problem getting single digit SDs and 20-30 ES for 10 round strings using only sized/trimmed hornady brass...no other prep and throwing powders with 2 different chargemasters

 

[Dthomas3523]

My point is that guys who are suddenly experts on how people are wasting time doing OCW tests were on here talking about their own OCW tests and helping guys read their OCW tests a short time ago. Now some new info is out there and suddenly they have no idea what anyone would be looking for in an OCW or why they would want to do something so futile. I get that there’s a new school of thought and maybe it works great but that doesn’t make OCW invalid. You notice the prerequisite for the new line of thinking is you have to have absolutely exact powder charges and preferably buy enough of a lot of powder to last the whole barrel. That sounds like a good way to avoid a POI shift should you pick a random charge that’s on the edge of a POI shift. I’m fine with those “from a time before” loads that can go .1 and usually .2 or more up or down and still shoot the same.

I’ll agree that a lot of guys can’t shoot good enough and spend 4 range trips running OCWs and their targets are a mess that show nothing. This is apparent in a lot of the OCW targets that get posted here. But an OCW shot correctly has pretty much always shown me where I should be via POI in about 35 rounds. I’ve loaded for everything from a light weight hunting rifle to large and small frames to heavy barreled magnums. I always end up with good loads that hold up.

Let’s say maybe it’s not the POI data that matters. What have I lost? I got a good load and I would have shot the 35 rounds that were used in the OCW to find max charge and get velocity data anyway. Why not do it? Does it really make more sense to just pick a random charge? What are you gaining by doing that? My consequence for being wrong about OCW being useful is that there are no consequences. I shot 35 rounds that I would have shot anyway. The consequence for using a random charge(if you happen to land on the very edge of a shift and something changes) could be an unexplained POI shift that will make your tail irresistible to chase for an unknown amount of time. I don’t see the reason not to do an OCW if you can shoot good enough to read/believe the target. I just don’t see the huge benefit that’s being implied or how it’s so much better.

Obviously you can just pick a charge if you’re using a barrel tuner because you can change your harmonics via the tuner rather than the charge weight. But using a barrel tuner while also saying OCW is pointless makes no sense to me. That’s basically taking the position that a different charge weight won’t change the frequency/velocity of the harmonic waves in the the barrel. I’m no physicist but I’d imagine a different size explosion would create different harmonic waves in the barrel. If thats the case that means OCW tests are valid. And again- heavy, inherently accurate barrels are not good test subject to gather data on this because they will be affected much less by small changes in charge weight; especially in small calibers.

You’re reading into things way too much.

I’ll help people with interpreting their results. That doesn’t mean I think they are doing things the most efficient way.

It’s an older method and can be done faster and more efficient. It takes the entire picture into consideration. This was at a time where we didn’t have the best tools to break things down into smaller chunks.

 

[Dthomas3523]

Also, you can go back through this site for years and see how people’s opinions have changed.

Quoting shit from the post only solidified how we are progressing and understanding things differently.

All our equipment and methods have changed radically since the 90’s. It makes sense that with that will come changes in load development.

 

[Precision Underground]

Also, you can go back through this site for years and see how people’s opinions have changed.

Quoting shit from the post only solidified how we are progressing and understanding things differently.

All our equipment and methods have changed radically since the 90’s. It makes sense that with that will come changes in load development.

The examples I’m thinking about aren’t from the 90s.... they were like a month or two ago.

What are you understanding differently? That you can tune harmonics with a tuner rather than with charge weight? Either way you are synchronizing your bullet and your harmonics. You’re just doing it from the opposite end. I don’t see anything new to understand. To me it actually goes to reinforce that an OCW makes sense if you don’t want to use a tuner. You’ve yet to say why using 35 rounds that I would be shooting anyway to do an OCW is inferior. When I’m done I can let the CM throw charges without OCDing over .01 grains or spending a grand on a scale. I can almost always use a new lot of powder and just recheck speed unless one of the lots was extra wet or dry. How is what you’re doing better? Serous question. I haven’t watched Erik’s videos so maybe I’m missing something.

 

[Dthomas3523]

The examples I’m thinking about aren’t from the 90s.... they were like a month or two ago.

What are you understanding differently? That you can tune harmonics with a tuner rather than with charge weight? Either way you are synchronizing your bullet and your harmonics. You’re just doing it from the opposite end. I don’t see anything new to understand. To me it actually goes to reinforce that an OCW makes sense if you don’t want to use a tuner. You’ve yet to say why using 35 rounds that I would be shooting anyway to do an OCW is inferior. When I’m done I can let the CM throw charges without OCDing over .01 grains or spending a grand on a scale. I can almost always use a new lot of powder and just recheck speed unless one of the lots was extra wet or dry. How is what you’re doing better? Serous question. I haven’t watched Erik’s videos so maybe I’m missing something.

I didn’t say you were quoting posts from the 90’s.

I’m saying OCW is an old method and can be done faster.

I’m also not going to retype the same things that have been typed or talked about at length because you haven’t explored other options. Not to mention he makes a bit of profit off his classes and his Patreon page. So, if it can’t be gleaned from his free videos or podcasts, I’m not going to put his work out there and undercut him.

Listen to that podcast. Look up Erik’s stuff and make up your own mind. No one is saying you have to do it one way or another.

But to come in here the way you have and then saying you don’t even know the other ways out there, I’m not going to go back and forth because you haven’t done any homework.

 

[Dthomas3523]

What I will absolutely say, you can do an OCW, or any other load development method then go to a PRS match.....

And you will not have any advantage over a shooter of equal skill level who has loaded his ammo with quality components and solid loading methods, who didn’t do anything except chrono and dope his load.

 

[Precision Underground]

I didn’t say you were quoting posts from the 90’s.

I’m saying OCW is an old method and can be done faster.

I’m also not going to retype the same things that have been typed or talked about at length because you haven’t explored other options. Not to mention he makes a bit of profit off his classes and his Patreon page. So, if it can’t be gleaned from his free videos or podcasts, I’m not going to put his work out there and undercut him.

Listen to that podcast. Look up Erik’s stuff and make up your own mind. No one is saying you have to do it one way or another.

But to come in here the way you have and then saying you don’t even know the other ways out there, I’m not going to go back and forth because you haven’t done any homework.

“Come in here the way you have” lol. Ok.

I’m telling you from what you’ve typed I don’t see the revolutionary part of it. And you have dismissed my question of how using 35 rounds I would have shot anyway is somehow “hard” and needs to be changed. I guess I just don’t get it

 

[Macht]

Obviously you can just pick a charge if you’re using a barrel tuner because you can change your harmonics via the tuner rather than the charge weight. But using a barrel tuner while also saying OCW is pointless makes no sense to me. That’s basically taking the position that a different charge weight won’t change the frequency/velocity of the harmonic waves in the the barrel. I’m no physicist but I’d imagine a different size explosion would create different harmonic waves in the barrel. If thats the case that means OCW tests are valid. And again- heavy, inherently accurate barrels are not good test subject to gather data on this because they will be affected much less by small changes in charge weight; especially in small calibers.

Can you draw me a picture of what you think a "harmonic wave" in the barrel looks like, and then draw it again after a 0.2 grain change in charge mass?

 

[NamibHunter]

I think the OP said OCW and related methods are not needed in PRS to figure out optimal charge weight, and there is no need to find a node, because heavy barrels whip a lot less, and the targets exceed 1 MOA, but seating depth optimization is still needed (to exploit positive compensation).

[Or use a barrel tuner in place of seating depth adjustment.]

He excluded BR and F-class rifles. IMHO, in those games finding a good node is valuable. Same applies to many/most hunting rifles. Horses for courses argument.

For those that want to continue to use OCW to tune all their rifles, there is no real disadvantage other than one additional range trip, which is a one hour effort, 30-50 bullets, and a small amount of barrel life.

I get some personal satisfaction from shooting the occasional group in the ones, and get a kick out of shooting a target with all the groups below 0.35”, so i will probably continue to use OCW load workups.

And every time I go hunt, and i have to shoot without a rear support, i realize yet again that my aiming accuracy is 1.5” at best, and that head shots are too risky. Neck shots still work, but only at fairly short distances. It is often not possible to shoot prone during a hunt, too much grass in the way. My 1/4” hunting rifle is better than i can exploit, and probably over specced, but it surely helps my self confidence!

 

[Precision Underground]

Can you draw me a picture of what you think a "harmonic wave" in the barrel looks like, and then draw it again after a 0.2 grain change in charge mass?

Again, It makes it easier to think about as a wave. It’s obviously not something you can see or even something that has been measured as far as I know. Is it muzzle movement or is it vibrations disturbing the exiting bullet as they bounce back and forth from receiver to muzzle? My guess is vibrations. I don’t know. But I don’t think anyone contests that harmonics exist or that charge weight, seating depth, tuners, etc... can all affect the relationship between the bullet and the harmonics of the barrel. I’m not a physicist so I can’t tell you the exact mechanism not can I draw it.

 

[stello1001]

So 41.2 grains of H4340 in a Peterson case with a 140 hybrid should shoot pretty damn well in just about any match 6.5 chamber?

 

[John Glidewell]

Again, It makes it easier to think about as a wave. It’s obviously not something you can see or even something that has been measured as far as I know. Is it muzzle movement or is it vibrations disturbing the exiting bullet as they bounce back and forth from receiver to muzzle? My guess is vibrations. I don’t know. But I don’t think anyone contests that harmonics exist or that charge weight, seating depth, tuners, etc... can all affect the relationship between the bullet and the harmonics of the barrel. I’m not a physicist so I can’t tell you the exact mechanism not can I draw it.

Why I like thinking about it in terms of optimal barrel time. I run .5 and 1.0 in calculator. Look at barrel time closest to 2-3 grains below established safe max and shoot across it. Has worked many times, different rifles and cartridges and many times shooting less than 20 rounds.

 

[AManWearingAHat]

Im curious if anyone else has had this experience. I use what you are all describing as the OCW method. Load a batch of 50 or 100, shoot a bunch of groups, and take the load that produces the best group. I know its more wasteful compared to other methods, but I genuinely enjoy finding loads this way and makes for a good range day.

Now typically I chronograph after I pick my charge when I've loaded a batch to get velocities for dope charts and my ballistics app. Ive found that my best performing loads also chronograph very well. Is this a symptom of success or have I just been lucky?