Scott Satterlee ‘OCW’ Question

[OzzyO20]

Decided to try out some Berger 140’s and had recently read the Scott Satterlee 10-round load development article from the 6.5 Guys. Ran a ladder, and got a few flat nodes, not they aren’t as ‘long’ as the ones referenced in the article. I’ll post a pic below. I’m guessing take the higher charge and load in the middle now?

Also, I’ve never really found pressure on this rifle and still have a fair amount of case capacity (Lapua 6.5 CM H4350). The last number is phenomenal speed for a 140, would you go up another few .3 increments and see if there’s another flat spot around there?

 

[Triggerf16]

I’d go for that node at 2805. That is a common accuracy speed for the Creedmoor.

 

[OzzyO20]

Tried 42.8 and wow is all I can say. Next step is seating depth and it should be gtg.

 

[OzzyO20]

Hasty groups, but even then not terrible. I think with a seating depth test this will be phenomenal.

 

[chavezz556]

41.5 and a 140 seems to be the ticket for me.. I'm about 30fps faster though w/eldm's

I stopped at max charge weight 42 (per Hornady

 

[CanSniper]

Keep us informed please. I am curious if ES/SD holds up after you change seating depth. I have been playing with this method as well. Very curious as to your results as to compare notes.

 

[OzzyO20]

Ok, seating depth test today. Two pretty solid groups. The .015” jump group included the cold bore and came in at .442 MOA, and the .035” came in at .3925 MOA.

I didn’t run these over a chrono because I wanted to see what they did with zero influence from the Magnetospeed.

If everything works out, I’m going to load 10 of each tomorrow and run them over the MS. I’ll let you know if the ES/SD hold up @CanSniper

I have a feeling the .035” jumped load will send the numbers up a bit, but if it doubled it, I’m at 4.4 SD lol.

 

[OzzyO20]

Pics I took upside down like an idiot.

 

[OzzyO20]

@CanSniper it held up and I’m running with it.

 

[CanSniper]

@CanSniper it held up and I’m running with it.

Good to hear! Not much to improve on that!

 

[Milo 2.5]

@CanSniper it held up and I’m running with it.

Let us know how that load does at 1K.

 

[OzzyO20]

Let us know how that load does at 1K.

Hopefully I can get over to the far range soon.

 

[CanSniper]

I really want this method to work for me because it makes alot of sense. How ever I have not had as good of results. Probably some thing I am doing wrong. Good it worked for you though. I have not given up, and the test gives me some valuable info on velocity ranges and max pressure with minimal component usage. Definitely interested in your results so far. With the groups you are shooting, and ES number like that, I am sure it will hold up at distance. Keep us informed please.

 

[jb1023]

I loaded up some rds this weekend for a Thursday range trip, weather pending, to compare the 2 methods. I loaded 11 rds for a Satterlee test and 24 for a regular OCW test. I will run the Satterlee first with 60 seconds between shots. Let the barrel cool completely, 30+ min, then run the OCW in 3 shot groups with 120 seconds between groups. I'm curious to see if both methods lead me to the same end result. I will post up the results, if this actually happens, and I'm not having a bad day.

 

[Deleted member 113831]

I really want this method to work for me because it makes alot of sense. How ever I have not had as good of results. Probably some thing I am doing wrong. Good it worked for you though. I have not given up, and the test gives me some valuable info on velocity ranges and max pressure with minimal component usage. Definitely interested in your results so far. With the groups you are shooting, and ES number like that, I am sure it will hold up at distance. Keep us informed please.

The reason it works for some people, is they are using relatively tight chambers, with short throats, and heavy barrels with relatively small calibers. So basically, the only element they are changing much is the powder charge. All other aspects are already locked into a very narrow window.

The chances of this working with any random factory chamber are slim. I'm not saying it CAN'T work....just saying that any favorable outcome is just as likely to be coincidental.

 

[CanSniper]

I wasn't using what i would consider to be loose or random factory chambers.

 

[OzzyO20]

For what it's worth, I'm using a factory AI AT in 6.5 CM. I honestly don't know if my chamber is tight or not as this if the first rifle I've ever reloaded for and I'm still learning a lot.

 

[Deleted member 113831]

I wasn't using what i would consider to be loose or random factory chambers.

I can't think of any principle which would cause combustion of gasses to basically stutter step in certain places.

There is a point at the top of the pressure curve where the burn rate of the charge, balanced against the total weight of the ejecta and the force of the bullet engraving, reach the point of diminishing returns. Maybe at this point there would be a flat spot.

However, the individual characteristics of the powder / cartridge / bullet / chamber combination would dictate the size of this spot as well as how spikey it became when passing it.

Until a powder reaches it's optimal pressure range, which will most likely be somewhere within 3% of maximum for that rifle / load combination, any flat spots are going to be an artifact of rounds simply falling close together in speed do to random chance within the overlapping extreme spreads of that charge range.

 

[trob_205]

So I use this method but with a minor twist, or extra step, or however you want to look at it. Still never actually shooting groups. I load up a total of three test. Run them all over the chrono lowest charge to highest, then highest to lowest, then lowest to highest again. I give time to let the gun cool between each test and somewhere around a min or two between rounds within the test (always shooting as fast as I can after closing the bolt to minimize cooking time). I record all the numbers and go back and look and not just flat spots but the small sample of ES I just got per charge weight. Yes I know it’s not enough to claim ES per charge weights, but it’s definitely enough to get a idea of what’s happening. It might be overkill, but my OCD brain likes the data verified. All while just shooting into a berm taking me out of the equation.

 

[pitdog85]

I recently shot a ladder test at 350m whilst chrono at the same time, the velocity flat spots in my test corresponded with the highest vertical distance between shots, the loads that held tight vertical on target (was going up in 0.3g increments) had large velocity changes!!!! I went with what the target showed compared to what the velocity flat spots were.

 

[trob_205]

I recently shot a ladder test at 350m whilst chrono at the same time, the velocity flat spots in my test corresponded with the highest vertical distance between shots, the loads that held tight vertical on target (was going up in 0.3g increments) had large velocity changes!!!! I went with what the target showed compared to what the velocity flat spots were.

I would just verify at different ranges unless you always are going to shoot 350m. Positive compensation is a possibility.

 

[OzzyO20]

Update: So I didn't get to go to the 1,000 yard range this weekend (it was my birthday and my fiancé had other plans). Also, I ran out of the lot of H4350 I used to work up the load. Thought I had 2 1# jugs, but the other jug was a different lot. So I switched to an 8# jug and hoped for the best. This lot is a tad slower than the numbers I was getting. However, I still was able to keep the SD at 3.2 over 5 rounds and sub 1/2 MOA. I'm not sure what the weather is going to do, and I may send my S&B off to get my one free disassembly and cleaning since it's December and the trash weather is coming. If I get lucky one weekend, I'll try and check it out.

I'm going to be getting a new 6XC barrel soon, so come spring time I'll revisit this with a new caliber and see if the results are similar.

 

[Forward543]

I think the satterlee method works if you are narrowing down a known load. Look up OCW from Dan Newberry. I use both.

 

[OzzyO20]

I think the satterlee method works if you are narrowing down a known load. Look up OCW from Dan Newberry. I use both.

I tried this as an expedited alternative to OCW, so far it has done well. Need a tweak following the powder lot difference to see if I can get back in that 2,810 FPS range with the 140's.

 

[Deleted member 113831]

I think the satterlee method works if you are narrowing down a known load. Look up OCW from Dan Newberry. I use both.

I tried this as an expedited alternative to OCW, so far it has done well. Need a tweak following the powder lot difference to see if I can get back in that 2,810 FPS range with the 140's.

I would be interested to know where you both landed in relation to your max charge. What percentage are you from max?

 

[OzzyO20]

I would be interested to know where you both landed in relation to your max charge. What percentage are you from max?

I know this is far from what you want to hear, but I never went high enough to find any pressure signs to begin with.

 

[arm017]

The satterlee method has gained popularity because it is concise. It takes a field of variables and simplifies them to be manageable to the everyday man. The issue is that it ignores statistics. We like to feel as if we have control over something. We feel warm and fuzzy following a scientific process eliminating variables one by one. Trying to understand what makes a difference and what does not. So what is the best method of load development @Skookum

 

[Deleted member 113831]

The satterlee method has gained popularity because it is concise. It takes a field of variables and simplifies them to be manageable to the everyday man. The issue is that it ignores statistics. We like to feel as if we have control over something. We feel warm and fuzzy following a scientific process eliminating variables one by one. Trying to understand what makes a difference and what does not. So what is the best method of load development @Skookum

I wouldn't feel confident in saying that there IS a best method. I have a way that makes sense to me and seems to work. But I doubt a 1000 yard benchrester would use it.

I really am only making 2 assertions:
1) The flat spots that are supposed to exist will most likely show up within the top 3% of charge weight before pressuring out. That is my hypothesis.

2) Flat spots that seem to present themselves at lower pressures are most likely artifacts of overlapping variances in ES, and if more rounds were shot, a normal progression of average velocity would be evident.

This my working theory that I am still gathering data on. I want to know that it is statistcslly solid, and then I want to know exactly why it works before I hang my hat on it.

 

[Milo 2.5]

The satterlee method has gained popularity because it is concise. It takes a field of variables and simplifies them to be manageable to the everyday man. The issue is that it ignores statistics. We like to feel as if we have control over something. We feel warm and fuzzy following a scientific process eliminating variables one by one. Trying to understand what makes a difference and what does not. So what is the best method of load development @Skookum

I had just hit unwatch for this thread, I'm back in,lol

 

[Deleted member 113831]

I know this is far from what you want to hear, but I never went high enough to find any pressure signs to begin with.

Just trying to fill in some puzzle pieces brother.

Good shooting

 

[Lowlight]

Scott is here, you can ask him if he is around to answer

@sstacllc

 

[arm017]

Scott is here, you can ask him if he is around to answer

@sstacllc

I figured he would be tired from wreckin shop at the PRS finale this weekend.

But in subsequent @sstacllc conversations, he has mentioned how it is a tool and not applicable in all situations. And I have seen that play out in my world as well. I partly employ his method with expanded 10 shot groups with a LR whilst doing a modified ish OCW test and then out to distance. I have found that when there is confusion and bickering even amongst top level guys, there is usually no perfect solution.

@Skookum - I agree- I have gravitated toward testing near full powder charge as well.

 

[sstacllc]

I would just verify at different ranges unless you always are going to shoot 350m. Positive compensation is a possibility.

Yes positive compensation exist and is most like the cause of tight groups at distance with numbers that would say different all though it takes a huge VE spread to cause noticeable vertical at 350 m

 

[sstacllc]

I wouldn't feel confident in saying that there IS a best method. I have a way that makes sense to me and seems to work. But I doubt a 1000 yard benchrester would use it.

I really am only making 2 assertions:
1) The flat spots that are supposed to exist will most likely show up within the top 3% of charge weight before pressuring out. That is my hypothesis.

2) Flat spots that seem to present themselves at lower pressures are most likely artifacts of overlapping variances in ES, and if more rounds were shot, a normal progression of average velocity would be evident.

This my working theory that I am still gathering data on. I want to know that it is statistcslly solid, and then I want to know exactly why it works before I hang my hat on it.

I totally agree that there isn't a best method I think just about every method out there will yield some level of results. I also think the type of sport or application has some nuance as well. A bench rest or F class guy will probably not use the VE flat spot method because they are looking for positive compensation. They are looking for the highest point of deflection with the slowest bullet and a 20-30 FPS ES is good for them. Inn my sport where the cone of fire has t be small from 35 yards to 1700 I'm looking for tight ES and will sacrifice some precision to achieve it. I ralrely have a rifle that shoots over 1/4 with my loading technique and most shoot much tighter. I have used The VE technique on factory hunting guns with great success as well.

 

[sstacllc]

I figured he would be tired from wreckin shop at the PRS finale this weekend.

But in subsequent @sstacllc conversations, he has mentioned how it is a tool and not applicable in all situations. And I have seen that play out in my world as well. I partly employ his method with expanded 10 shot groups with a LR whilst doing a modified ish OCW test and then out to distance. I have found that when there is confusion and bickering even amongst top level guys, there is usually no perfect solution.

@Skookum - I agree- I have gravitated toward testing near full powder charge as well.

Most of my really good nodes are above what the book would call max charge. I really like to use slow for caliber powder.

 

[Deleted member 113831]

Most of my really good nodes are above what the book would call max charge. I really like to use slow for caliber powder.

So with something like a 6.5CM you are using something in the 4831 burn rate with 147's and stacking it hot?

I had wondered where the flat spots were showing up for you. I have watched the 6.5 guys video a couple of times but I don't remember you being specific on that point. That supports my theory that they (the flat spots) are showing up at the top of the pressure curve where the charge has reached the point of diminishing returns.

I would interested to know your chamber dimensions, especially your neck diameter, throat diameter, freebore and lead angle, and how far off the lands you are running the bullets.

 

[sstacllc]

So with something like a 6.5CM you are using something in the 4831 burn rate with 147's and stacking it hot?

I had wondered where the flat spots were showing up for you. I have watched the 6.5 guys video a couple of times but I don't remember you being specific on that point. That supports my theory that they (the flat spots) are showing up at the top of the pressure curve where the charge has reached the point of diminishing returns.

I would interested to know your chamber dimensions, especially your neck diameter, throat diameter, freebore and lead angle, and how far off the lands you are running the bullets.

My reamer dimensions are loose. SAAMI spec plus a little extra feebore and neck clearance. My RDFs seem to like that. I think we can get carried away attempting to maximize throat life by reducing freebore and that can lead to finicky stuff happening, just a theory and I have no proof. I look at pressure as the same as velocity. I can't measure pressure don't have the equipment, so I look at how fast the bullet is going and try to find a sweet spot. Sometimes that node is very small and sometime there are ghost nodes (looked good the first time through but wasn't). I have used powders that were too slow and no matter how much I put in the bullet wouldn't go any faster because there wasn't enough time to burn it all. We can take the 6.5 as an example. I typically look for nodes around 2800 with 140s. It doesn't seem to matter which 140 or powder primer brass combo 2800 usually yields great numbers and precision. I know some guys find nodes in the high 2800 low 2900 but that is a stretch for my reamer dimensions. I've also noticed that small rifle primers and efficient cartridges with low turbulence do not behave the same as a more overbore cartridge. A rule of thumb for me is less than 35 gr cartridge I use .1 increments 35-55 get .2 55-75 get .3 over that is a guess cause I don't own one. Right now in my 6 creed I use RE 23 with 115s for 2950 and RE 16 with 105s for 3060. In my 7 SAUM I run RE 23 with 185 for 2900. 308 gets 8208 with 175 class for 2745 and RE 16 with 200+ pills for 2650 (XM action COAL 3.2)
The VE technique is the same basic concept as OCW but with a chrono
There is some merit to optimal barrel timing theory but there is more going on than a wave up and down the barrel
There is a pressure bulge behind the bullet
There is torque and rotational movement
There is also some vertical movement when the action flexes at the recoil lug.
A lot of these can be mitigated but I'm not sure to what extent. I know my smith clocks the barrel at 12, but the latest batch of Proofs I got have less than .002 run out so its very hard to find 12 and a wast of time. I won't glue my action into the chassis because I need to be able to disassemble after a dusty muddy match. I think muzzle brakes actually aid in accuracy by dispersing the gas laterally and not influencing the bullet after it has left the crown.

 

[OzzyO20]

@sstacllc When I originally did this, I thought I had a 2nd and 3rd pound of H4350 from the same lot, and I in fact did not. The lot I'm running now is a little slower than the previous at the same charge weight. SD was still single digits, but nothing like I was getting in the first few posts I made. When you switch powder lots, do you just re shoot the 10 round test or add in .1 increments to get back to the speed you were at (getting to the accuracy nodes being speed based idea)?

 

[arm017]

My reamer dimensions are loose. SAAMI spec plus a little extra feebore and neck clearance. My RDFs seem to like that. I think we can get carried away attempting to maximize throat life by reducing freebore and that can lead to finicky stuff happening, just a theory and I have no proof. I look at pressure as the same as velocity. I can't measure pressure don't have the equipment, so I look at how fast the bullet is going and try to find a sweet spot. Sometimes that node is very small and sometime there are ghost nodes (looked good the first time through but wasn't). I have used powders that were too slow and no matter how much I put in the bullet wouldn't go any faster because there wasn't enough time to burn it all. We can take the 6.5 as an example. I typically look for nodes around 2800 with 140s. It doesn't seem to matter which 140 or powder primer brass combo 2800 usually yields great numbers and precision. I know some guys find nodes in the high 2800 low 2900 but that is a stretch for my reamer dimensions. I've also noticed that small rifle primers and efficient cartridges with low turbulence do not behave the same as a more overbore cartridge. A rule of thumb for me is less than 35 gr cartridge I use .1 increments 35-55 get .2 55-75 get .3 over that is a guess cause I don't own one. Right now in my 6 creed I use RE 23 with 115s for 2950 and RE 16 with 105s for 3060. In my 7 SAUM I run RE 23 with 185 for 2900. 308 gets 8208 with 175 class for 2745 and RE 16 with 200+ pills for 2650 (XM action COAL 3.2)
The VE technique is the same basic concept as OCW but with a chrono
There is some merit to optimal barrel timing theory but there is more going on than a wave up and down the barrel
There is a pressure bulge behind the bullet
There is torque and rotational movement
There is also some vertical movement when the action flexes at the recoil lug.
A lot of these can be mitigated but I'm not sure to what extent. I know my smith clocks the barrel at 12, but the latest batch of Proofs I got have less than .002 run out so its very hard to find 12 and a wast of time. I won't glue my action into the chassis because I need to be able to disassemble after a dusty muddy match. I think muzzle brakes actually aid in accuracy by dispersing the gas laterally and not influencing the bullet after it has left the crown.

Dude - That's awesome.

Have you found correlation between twist rate and size of node- or rather appropriately matched bullet/twist rate?

 

[Deleted member 113831]

My reamer dimensions are loose. SAAMI spec plus a little extra feebore and neck clearance. My RDFs seem to like that. I think we can get carried away attempting to maximize throat life by reducing freebore and that can lead to finicky stuff happening, just a theory and I have no proof. I look at pressure as the same as velocity. I can't measure pressure don't have the equipment, so I look at how fast the bullet is going and try to find a sweet spot. Sometimes that node is very small and sometime there are ghost nodes (looked good the first time through but wasn't). I have used powders that were too slow and no matter how much I put in the bullet wouldn't go any faster because there wasn't enough time to burn it all. We can take the 6.5 as an example. I typically look for nodes around 2800 with 140s. It doesn't seem to matter which 140 or powder primer brass combo 2800 usually yields great numbers and precision. I know some guys find nodes in the high 2800 low 2900 but that is a stretch for my reamer dimensions. I've also noticed that small rifle primers and efficient cartridges with low turbulence do not behave the same as a more overbore cartridge. A rule of thumb for me is less than 35 gr cartridge I use .1 increments 35-55 get .2 55-75 get .3 over that is a guess cause I don't own one. Right now in my 6 creed I use RE 23 with 115s for 2950 and RE 16 with 105s for 3060. In my 7 SAUM I run RE 23 with 185 for 2900. 308 gets 8208 with 175 class for 2745 and RE 16 with 200+ pills for 2650 (XM action COAL 3.2)
The VE technique is the same basic concept as OCW but with a chrono
There is some merit to optimal barrel timing theory but there is more going on than a wave up and down the barrel
There is a pressure bulge behind the bullet
There is torque and rotational movement
There is also some vertical movement when the action flexes at the recoil lug.
A lot of these can be mitigated but I'm not sure to what extent. I know my smith clocks the barrel at 12, but the latest batch of Proofs I got have less than .002 run out so its very hard to find 12 and a wast of time. I won't glue my action into the chassis because I need to be able to disassemble after a dusty muddy match. I think muzzle brakes actually aid in accuracy by dispersing the gas laterally and not influencing the bullet after it has left the crown.

I'm not sure I buy into the OBT theory wholesale. It is interesting though. Do you think positive compensation might be happening in your case? Positive compensation combined with low ES and low SD due to the 100% load density you are running could be the key. Isn't that what the 1000 yard benchrest guys are doing with the Audette style ladder tests at distance?

 

[sstacllc]

@sstacllc When I originally did this, I thought I had a 2nd and 3rd pound of H4350 from the same lot, and I in fact did not. The lot I'm running now is a little slower than the previous at the same charge weight. SD was still single digits, but nothing like I was getting in the first few posts I made. When you switch powder lots, do you just re shoot the 10 round test or add in .1 increments to get back to the speed you were at (getting to the accuracy nodes being speed based idea)?

I start over for sure and just do what the bullet and chrono tells me

 

[sstacllc]

Dude - That's awesome.

Have you found correlation between twist rate and size of node- or rather appropriately matched bullet/twist rate?

Man I don't know honestly I haven't done this long enough or burned up enough barrels to really form a theory on it

 

[sstacllc]

I'm not sure I buy into the OBT theory wholesale. It is interesting though. Do you think positive compensation might be happening in your case? Positive compensation combined with low ES and low SD due to the 100% load density you are running could be the key. Isn't that what the 1000 yard benchrest guys are doing with the Audette style ladder tests at distance?

I'm sure that is what the BR guys are doing. It's probably the only way to shoot groups as small as they do. I'm not sure about PC I'm not looking for it in my load. I typically find a good VE node and run it out. Typically the tight ES really show up at distance. I know before I used the system I would get some crazy tight groups at 500 which is all I had at the time in Western WA and when I ran them out at distance they vertical would unravel like a ball of yarn played with by a kitten. I'm positive that I was seeing the negative effects of PC. I was tuning a load for 500 thinking I would be good past that

 

[arm017]

Man I don't know honestly I haven't done this long enough or burned up enough barrels to really form a theory on it

But you're our PRS Jesus?? But seriously Scott, Thank you for being a positive voice in the community. Your videos got me started down the dark side and have been instrumental in a lot of shooters kit. Thanks for your contributions.