Satterlee 10 Round Load Development

[centerfire]

Centrefire,

Well, at least we agree that Satterlee does not work in all situations.

And if you want to compound the validation by suggesting it is not working because the OAL is not being tested and lots of different powders are not being tested then again, how will you ever know that the lowest SD/velocity spread produces the best results at 1K unless you test all of these other permutations across all other loads to produce the tightest groups at 1K?

Are you saying that because my SD's were not low enough across all loads that it somehow confounds Satterlee, and that Satterlee only works with single digit SD's? Surely, as long as all variables across all loads are equal that shouldn't matter. Yes, I could now tinker with powder and primers and technique to tighten the groups further (and in doing so tighten the SD's) but how much of doing this is enough to qualify for Satterlee?

Tightest groups is not a sidebar, this is what you are trying to predict at 1K. Finding the tightest velocity nodes with the lowest round count at the muzzle is not the aim of the exercise, it is the mediating variable to finding the tightest groups at long range. And in this situation it did not work.

What I'm saying is that your spreadsheet suggests your single digit SD's surrounded by high SD's are telling you that your load is going to have vertical stringing problems as soon as you introduce environmental variables. The purpose of testing for velocity nodes is to find a load that is insensitive to pressure changes, beit heat or imprecise powder charges. Once you find a acceptable node, regardless of group size, you then shoot seating depth groups looking for the best accuracy. I would absolutely reshoot that low SD group and charges surrounding it to validate that your chrono results are actually accurate with larger samples. Ignore the group size until you start to work on it with seating depth adjustments.

I'd be willing to bet those low single digit SD's on the spreadsheet are actually much higher when you either shoot more groups or larger round count groups. Further, if you only shoot those 223 loads at 300 yards then most of this is just academic because you likely won't see a difference inside of 600 yards. The "Satterlee Method" attempts to locate the flat velocity nodes in a small number of rounds, not find the tightest group. As you pointed out, it is statistically irrelevant and often when you do a lot chrono testing (as you did), you identified nodes aren't really nodes after all. Try shooting the 23.5gr group again with 10 or 15 rounds and see what the SD's are.

Personally I would not use that load without more validation. 8208 does change velocity with heat and it wouldn't take much to change your velocity enough to swing the ES and SD's. I shoot a lot with some fairly competitive F-Class shooters and they would not use what you posted no matter what the group size is at 100 yards.

Also, thank you for taking the time to test this out and posting it for everyone to see. This is valuable for everyone following it.

[centerfire]

284 Winchester load development logbook showing SD's and velocity nodes. F-Open

[Klem]

Centrefire,

To clarify - I shot at 100 (not 300), using H4895 (not 8208), I have shot a 15rd group with that Tightest Group load (it is on the page: the left hand column), and I am an F-Class shooter too. I agree, I wouldn't use H4895 or 8208 either; I prefer Varget, we all did.

At least we also agree that 10rds is not enough to discount any load from being possibly the best. We agree that shooting is a game of statistical averages. The more you shoot, the more valid and therefore generalisable the results.

I agree with you that the low SD's surrounded by higher SD's are potentially a statistical anomally, as is that great, but anomalous group. I acknowledged this by replacing it with the next best group for the long range simulation. I agree, more rounds need to be shot. But then again, Satterlee is saying look for the low SD's and once you find this focus on them, only. But how do you explain the best group coinciding with the second best SD, is this a validation of Satterlee or not?

I maintain that due to barrel harmonics and whip that bullets in a group can come out with the same MV but still be pointing in different directions. Satterlee with a focus on velocities only does not take this into account. I am convinced it is not correct in all situations and that means it is useless to me because without being able to discount results on a target I can never be sure the lowest SD is the most precise group.

[centerfire]

Centrefire,

To clarify - I shot at 100 (not 300), using H4895 (not 8208), I have shot a 15rd group with that Tightest Group load (it is on the page: the left hand column), and I am an F-Class shooter too. I agree, I wouldn't use H4895 or 8208 either; I prefer Varget, we all did.

At least we also agree that 10rds is not enough to discount any load from being possibly the best. We agree that shooting is a game of statistical averages. The more you shoot, the more valid and therefore generalisable the results.

I agree with you that the low SD's surrounded by higher SD's are potentially a statistical anomally, as is that great, but anomalous group. I acknowledged this by replacing it with the next best group for the long range simulation. I agree, more rounds need to be shot. But then again, Satterlee is saying look for the low SD's and once you find this focus on them, only. But how do you explain the best group coinciding with the second best SD, is this a validation of Satterlee or not?

I maintain that due to barrel harmonics and whip that bullets in a group can come out with the same MV but still be pointing in different directions. Satterlee with a focus on velocities only does not take this into account. I am convinced it is not correct in all situations and that means it is useless to me because without being able to discount results on a target I can never be sure the lowest SD is the most precise group.

I think we pretty much agree on all of it. I think it just comes down to luck sometimes. In other words, sometimes the 10 shot method identifies the node and sometimes it doesn't. I used it successfully on a 308 load with 150NBT; I was in the best node in 10 shots. The next rifle it took multiple powders and bullets and the 10 shot method never identified anything other than how to spend money and time at the range.

Like I said on page one, I only use it to record velocity and look for pressure.

[Lemonaid]

Bullet drop from two tested loads, one good ES the other not so good, using the Hornady Ballistic Calculator and the high and low velocity.
Monster 20 barrel. I knew SD and ES were important but this made me reevaluate what I need for long range.

load one is Speer 140 Hot core, 27.0 grains of Win 748, cci 450, Hornady case 5 shot group at 100=.838 ES=57

---------------------------300 yards----------------600 yards--------------1000 yards
2178---------------------23-------------------------141.7-------------------534.8
2235---------------------21.6-----------------------133.7-------------------505.2
----------------------------------------------------------------------------------------
---------------------------1.4-------------------------8-------------------------29.6

Load number 2 Sierra 120MK, RL15 29.3, cci 450 Hornady case 5 round group at 100 = 1.290 ES=18
2497---------------------17.8-----------------------111.9-------------------446.3
2515---------------------17-------------------------110.1-------------------438.9
--------------------------------------------------------------------------------------
------------------------------.8-------------------------1.8-----------------------7.4

"It's not what I don't know, It's what I think I know and is not true that is the problem!"

[Arkhangel5]

Klem,

Thx for answering my question.

I am also a F-Class shooter, use the .223 in mid range competition.

I drive an 80 Eld-M at 2940fps out of a 26in barrel, but acknowledge that I know this is on the hot side, but have been using this combo for the last 8 years.

Have shot at, but not competed with at 1000yds.

SY

[Lemonaid]

Link to Bolt Action Reloading on this topic! Note Primer test. https://www.youtube.com/watch?v=paUMACbJxTs

[Klem]

Lemon,

Good luck.

[Lemonaid]

Gavin Tube did a 6 Dasher load development with good results using the Satterlee method, may be of interest. https://www.youtube.com/watch?v=gyGoAL2F92M

[Klem]

As soon as he mentioned firing ten shots [only] and Satterlee my eyes glazed over.

To recap,

1. The 5 Satterlee's I fired were not repeatable. They display different 'speed nodes' each time. If you only fire one Satterlee you can be fooled into thinking the elastic and inelastic portions of the graph indicate something useful. If there is such a thing as a 'speed node' then this is proof that 1 round for each increment is not enough. Shooting is a game of statistical averages. The trouble is, when you shoot several Satterlee's and average them out the line straightens out and the 'speed nodes' are harder to delineate on a graph. There will still be a lowest velocity SD and Spread however and we can use this as an indicator of a 'speed node'.

2. Toobe invokes Satterlee; that consistent velocities produce the best results at long range. We dispelled that tenet by demonstrating how results on a target, and over a chrono at short range translate into results at long range using a ballistics calculator. The vertical spread of the most velocity consistent load on the target at long range was not smaller than the less consistent, but tighter group at 100. This comparison is now easily done with a LabRadar where you can shoot groups (without something hanging off your barrel) while at the same time record velocities.

Satterlee might work sometimes, but near enough is not good enough. Speed nodes are a mediating variable for tightest groups at long range. So too are group sizes at short range (100yds). My thoughts are, that rather than choose one method you use both, then extrapolate the best results to long range and see which theoretically translates into the tightest group. This requires at least 40 rounds for 4rd groups; which is not a big ask when you think about what is at stake. By that I mean the risk of believing you have found the best load and sticking with that for hundreds of rounds, not realising there was an even better load.

So, you need to fire more rounds, combine both methods, and at a target.

[Lemonaid]

Klem I think you (and data) have convinced me. I don't think I would have confidence in my load unless doing testing in complete ladders as you propose. Doing both as you posted is what I'm going with.
Thanks! I'm still interested in reading other's opinions for and against and their results.

[teppou]

I just got caught up on the thread; interesting stuff. One question that I have is that when you start to work on seating depth for a load, what size increments do you like to use? How dramatic a difference does that tend to make for your loads, particularly in a gas gun?

[Lemonaid]

Two links to start. https://precisionrifleblog.com/2020/...d-development/

http://www.barnesbullets.com/load-data/

I used to start at the lands and work back in .005 increments. I'm going to try the Barnes method next, it may be better for bullets that start out with a lot of jump due to magazine OAL limits and bullet geometry.

[Klem]

teppou,

Gas gunners don't have the luxury of loading all the way to the lands like bolt gunners. Unless you are prepared to hand-feed rounds into the chamber like long range Service Rifle matches, which of course defeats the purpose of a semi-auto.

Here is a list of OAL's bullets would have to be for a 2-thou jump to lands in a Lilja chamber. In all cases the mag prevents this from happening. Jumps are always longer in a gas gun which means incremental differences in OAL are going to be less noticeable and less meaningful. I load to the max steel mags will permit, 58mm/2.283" and leave it at that.



Happy to try different bullets and powders where differences are obvious and significant but I save COAL tuning for bolt guns where you can see differences, where subtle differences are more meaningful, and any cost in velocity is insignificant. At some stage you have to accept the limitations of the gun you are loading for and honestly question whether subtle changes from OAL are going to make a meaningful difference in how the gun is used - unless you just like to tinker.

[imaguy3]

I just got caught up on the thread; interesting stuff. One question that I have is that when you start to work on seating depth for a load, what size increments do you like to use? How dramatic a difference does that tend to make for your loads, particularly in a gas gun?

I'm playing with seating depth again on my load, I'm bored... using 123gr SST

At 1.656 base to ogive I was getting .8-1.2 moa

At 1.661 and 1.666 base to ogive I was getting 1.5moa

At 1.671 base to ogive I am getting .45 and .5 moa (only shot two 5 shot groups so far)

All those loads had SD's b/t 5 and 10