Satterlee load development method

[MJR]

Intrigued by the 6.5 Guys interview with Scott Satterlee and in need of developing a load for a 6.5x47 I thought I'd give it a try. The goal is to develop a good stalking load, I already use 129SST's in a 6.5x55 so I decided to try those as I already have some. Previously fired cases were cleaned, annealed, resized and trimmed. Varget was chosen for the powder as I have some left to use up and 14 cases were charged and bullets seated to give a 0.020" jump. Charge weights were 35.7 to 36.9 and two cases were loaded at each increment. This deviates from the Satterlee method as I believe he only loads one round at each increment but I wanted to see what deviation I got at each point. The loads were than shot using a Magnetospeed chrony and the results recorded. Here are the results:

35.7          2790   2759

35.9          2785   2783

36.1          2774   2801

36.3          2812    2807

36.5          2824    2829

36.7          2832    2831

36.9          2852    2832

There is a velocity plateau between 36.5 and 36.7 so the next stage is to load five rounds at 36.6 as the middle of the node and see what SD they will give.

Has anyone else tried this method and how did it work for you?

 

 

[VarmLR]

There also appears to be a flatish plateau between 35.9 and 36.3 which is a wider plateau.  I'd be trying 5 at 36.1 or 36.2 and checking ES.

I tried this with 69TMKs in 223 using one at each then loading to the mid point of an upper plateau.  It works and saves development rounds.

[furrybean]

Mike, I’ve tried this method with my faster twist .308 and 200’s and it seems to have worked well. I haven’t confirmed anything at distance but 100 yards is looking promising. 

[Cienfuegos]

El 2/4/2018 a las 11:47 a.m., MJR dijo:

Intrigado por la entrevista de 6.5 Chicos con Scott Satterlee y con la necesidad de desarrollar una carga para una 6.5x47, pensé que lo probaría. El objetivo es desarrollar una buena carga de acecho, ya uso 129SST en un 6.5x55, así que decidí probarlos porque ya tengo algunos. Las funciones se quemaron previamente, recocieron, redimensionaron y recortaron.Varget fue elegido para el polvo que ya tenía algo para agotar y 14 cajas fueron cargadas y las balas se sentaron para dar un salto de 0.020 ". Los pesos de carga fueron de 35.7 a 36.9 y dos casos fueron cargados en cada incremento. Esto se descargó el método de Satterlee como creo que solo se carga una ronda en cada incremento, pero quería ver que la migración recibía en cada punto Las herramientas se dispararon usando una trampa Magnetospeed y se registraron los resultados.

35,7 2790 2759

35.9 2785 2783

36.1 2774 2801

36,3 2812 2807

36.5 2824 2829

36.7 2832 2831

36.9 2852 2832

Hay una meseta de velocidad entre 36.5 y 36.7, por lo que la próxima etapa es cargar cinco rondas a 36.6 como la mitad del nodo y ver qué SD darán.

¿Alguien más ha intentado este método y cómo te funcionó?

 

 

 

[MJR]

Dan, thanks, interesting to hear others results. Cienfuegos, thanks for the graph it really helps identify the plateau.

[furrybean]

44.9-45.7gr N150 200H 2.390 OAL (SS) 2674, 2669, 2676, 2690 and 2690 fps

47.2-48.6gr N150 185J 2.386 OAL 2797, 2812, 2821, 2824, 2839, 2835, 2854, 2863fps

A few notes I took which also aligned with some of my previous loads (2690 with 200's and 2820 with Jugs)

[TJC]

I’ve used his approach but loaded in 0.1 increments. The flat spots were very easy to identify. 

[Andrew]

Is this new? I have used it of and on since I got my first (Tipico Time Meter) chronograph many years ago. One of the ballistic gurus from the White Sands Missile range was a bench rest shooter and long range fanatic. He shared this with me. At the time, a chronograph was not a common piece of shooting gear. My chest thumping about having a chronograph prompted his advice.  When you think of it, it makes perfect sense.~Andrew

[VarmLR]

I don't think it's new Andrew, as you rightly say, it has been known about for years.  It's probably fairly new to many shooters in the UK though.  OCW wasn't really widely known about or practised here until a few years ago but Dan Newbury wrote about it years back, and Precision Rifle Blog mentions it I think as far back as 6 or 7 years ago.  The idea of what's being popularised as the "Satterlee System" or "10 shot Load Development" is just a take on OCW which precision shooters have been using for some while to help with rapid load development.

However (there's always one!), people reading about the Satterlee system may wish to pause for breath before rushing out and hanging their hats on this method first time out, as Scott Satterlee himself explains that to work properly or reliably, a high degree of uniformity in case prep and load precision is essential.  

When I first tried this some while back, to pick loads to take further, I enthusiastically just went about my usual (rushed) brass prep and was disenchanted to see that results over several session were....err...a little erratic and not totally reliable!

You have to take extra care over brass prep and charge weights (and even how you fill the cases imho)  if you are to get accurate results that you can rely on.  

Brass prep stages for using this method that I use include, after tumbling, annealing, FL sizing and trimming (if needed) are then to batch brass by weight and to take extra care when measuring powder to be very consistent and accurate in measurement (I use two scales to cross check each load).  I then use a funnel with a long spout of about 6 inches and load each case in the same manner, before seating to within 1 or 2 thou to Ogive, checking each load.  Finally, I've found that using the Lee Factory Crimp really helps with neck tension consistency, so that now gets used each time.  Some of the lowest ES loads I've yet identified only came after adopting these methods.

Some will go further, some won't want to bother.

If being a bit anal about brass prep and loading isn't for you, then probably the Scott Satterlee method of load development isn't for you either. 

The standard OCW method allows for a little more deviation, which is why I suspect more people use it, as you are using averaged MVs and POIs of groups of 3 to 5 shots.

I'm a convert to the Satterlee system as each time I've taken care with prep, I've identified vary accurate loads usually within 10 to 15 shots and perhaps one or two groups to verify.

[Andrew]

Agreed on case prep and load prep. If not properly attended to , this method is just another way of chasing your tail. ~Andrew

[Chanonry]

Not guaranteed to find a nice flat spot in my experience. Some loadings do, others just give a nice linear(ish) trend in what were acceptable velocity ranges (for me). 

+1 on accuracy and consistency required in the loading process. If not the result is an illogical mess

[MJR]

I thought the idea of this method was to firstly reduce the amount of ammunition and hence components used to identify a stable velocity node and secondly to identify a charge weight variation where the velocity remained constant and therefore allow for case capacity variation and charge weight accuracy ? I'd agree re good case prep for accuracy but was hoping to avoid weighing cases and such like if possible. The cases I used we prepped using my usual routine and not weighed. There is obvious variation on some charge weights but had interpreted them as the equivalent of the scatter node in a OCW test, is that incorrect?

[VarmLR]

My thinking on this is that any deviations in case capacity will equal deviations in pressure..."so what" some may say as we're dealing with different loads.  Issue is that without consistency, you simply cannot trust the results as variations in pressure mean that the expected velocity profiles simply won't materialise, or at least, not quite as reliably.  It's not such a chore weighing brass, takes seconds and is worth it.

OCW should, with chrony data, tell you the same result BUT with greater cost in ammo. To get the best from OCW, theoretically anyway, the same attention to detail means more reliance on the end results.  Essentially, the aim of all these "systems" is to improve precision and efficiency in the load development process.  That means that precision at each step correlates with improved reliance on the end result, surely a worthwhile goal?  I remember starting out on load dev, that 50 rounds or more was not untypical, and 100 not out of the ordinary when trying to judge development purely on grouping at various ranges.  This method has so many advantages, takes far less time, is (for me any way) far more reliable at distance and far more economical.  Yes, you have to be ultra consistent with loads and brass prep but the proof of the pudding are things like consistent single figure ES/SD figures and better LR precision.

[Andrew]

To make this work you must have cases that are as close to exactly the same as possible. I would used same LOT, prepped identically then sorted and weighed to get my sample test cases. To randomly toss unlike cases together will give you very inconclusive results.~Andrew

[Fox Tales]

 I used this method to develop a 243 load , using both MV over the chronograph whilst doing point of impact tests (using the same aim point)

 I found that the MV 's in the  higher end of the plateau in this particular load development were where the POI's became very close to each other . A further 12 rounds and I had a 0.2" load . I would think that a sweet spot could occur anywhere within the plateau. 

 Conditions on the day were a breeze free 14°(so no wind drift to account for down range ) and I was using new Lapua brass.

 Certainly quicker than a previous load that I developed for the previous barrel , around 50 rounds .

[Murph]

On April 4, 2018 at 10:21 PM, VarmLR said:

My thinking on this is that any deviations in case capacity will equal deviations in pressure..."so what" some may say as we're dealing with different loads. Issue is that without consistency, you simply cannot trust the results as variations in pressure mean that the expected velocity profiles simply won't materialise, or at least, not quite as reliably. It's not such a chore weighing brass, takes seconds and is worth it.

 

OCW should, with chrony data, tell you the same result BUT with greater cost in ammo. To get the best from OCW, theoretically anyway, the same attention to detail means more reliance on the end results. Essentially, the aim of all these "systems" is to improve precision and efficiency in the load development process. That means that precision at each step correlates with improved reliance on the end result, surely a worthwhile goal? I remember starting out on load dev, that 50 rounds or more was not untypical, and 100 not out of the ordinary when trying to judge development purely on grouping at various ranges. This method has so many advantages, takes far less time, is (for me any way) far more reliable at distance and far more economical. Yes, you have to be ultra consistent with loads and brass prep but the proof of the pudding are things like consistent single figure ES/SD figures and better LR precision.

 

I use pretty much the same methods as yourself but with a couple of editions. I neck turn my brass as well as used a home made bullet straightening device which straightens my loaded rounds to under a thou. I do this when i seat the bullet then check,straighten then finish with the lee factory crimp die. I also did some experimentation with the factory crimp die tension. I run mine at 6 thou. I believe i shared this information with andrew on another thread a few years back. I did this experimentation when i had all my other reloading tuning done so as to really fine tune my load. I also have single digit es and sd as a result. 

 

[MJR]

Update.

Our local club had a range day today so the ideal opportunity to see how the load performed. Thankfully the forecast torrential rain held off with only a light shower mid morning with a wind value of 0.5mil at 300yds which later died down to .2/.3 after lunch at 500yds. 10 shots at 300yds produced 10 V bulls, 10 at 500yds produced 9 V bulls and 1 bull which i'm pretty sure was a bad wind call on my part as it was slightly right of centre at 3 o'clock. Vertical elevation was very good and as adjusted elevations perfect for the velocity.

Overall I'm very pleased with the results and plan on trying the same process again for 155TMK's in 0.308 but might reduce the initial test down to single loaded rounds as a trial and use sorted cases.

[furrybean]

Light shower!!!!

Bah lol

[brown dog]

I think I'm missing something; is this method chrono-only?

I 'buy-in' to OCW as it (to my understanding) empirically picks plateaus that align with optimum barrel time and, therefore, best ability to group.  Doesn't chrono-only give a 'theoretical' appraisal of the load that may, or may not, coincide with optimal barrel time?

[MJR]

Yes, that's pretty much it. This method specifically looks for several charge weights that produce similar velocity therefore low S/D and E/S. and load to the middle of that charge weight spread. The aim being to produce a load that performs well at extended range, specifically 600yd plus. Once the load is found it can supposedly be tuned by seating depth, I haven't done that as all 14 of the chrony'd rounds had a poi of less than an inch at 100yds and the rounds with the velocity plateau grouped smaller than the overall group at a similar poi test to OCW. I jumped straight to longer ranges and it seems to be accurate. I will test it in the tunnel though and see how it is and at longer range when I get opportunity. 

 

[MJR]

Dan, I think you inbox is full, been trying to pm you and it won't.

[VarmLR]

5 hours ago, brown dog said:

I think I'm missing something; is this method chrono-only?

I 'buy-in' to OCW as it (to my understanding) empirically picks plateaus that align with optimum barrel time and, therefore, best ability to group.  Doesn't chrono-only give a 'theoretical' appraisal of the load that may, or may not, coincide with optimal barrel time?

Yes, that's the idea.  I've only tried this with two cals but the two upper plateaus in each case have shot into a bug-hole.  In this case, into the 0.2's to 0.3's but that may just be coincidence as you point out, OBT/harmonics is the arbitor of POI consistency.

Consider it another way....10 shots to give you a couple of loads which you can then test for ES/SD and grouping. One of them will be a sweet spot.

[furrybean]

2 hours ago, MJR said:

Dan, I think you inbox is full, been trying to pm you and it won't.

There is room now Mike

[foxyloxy]

Excellent scores there MJR, well done. 

May I ask which load you opted for and what testing procedure you followed after the initial OCW test?

Also at what distance.

Thanks.

[MJR]

36.6gn was the load I opted for as its sits between the closest two loads of 36.5 and 36.7 and therefore allows for a little load variation. As I had opportunity I shot it at 300 and 500yds and it performed well. I will re chrony the 36.6gn load and check it for accuracy at 100yds shortly.