^^Quote:
Originally Posted by McNotty
This would be great to see.
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^^Quote:
Originally Posted by McNotty
This would be great to see.
Which seating depth would you pick as the worst? Clearly got some votes for 1.861" CBTO as the best.
10 rd each of 2 best/2 worst
or 20rd each of best, worst ?
I'm leaning towards the latter as 10rd groups should be expected to vary in size by + or - 40% from the average, and the MR will be less accurate than a 20rd measurement
'Load development' is a hobby in itself.
Got told by someone that 'cloverleaf was not good enough, one hole for 3-5 shots or nothing'
I asked them how many BR comps they were entering and winning as those results would definately place.
Silence...:psychotic: :ORLY:
Let’s get some close to solid data then. 20 each of the worst and best. Use the longest length load as the worst.Quote:
Originally Posted by gimp
I’ve been wanting to do this for ages but I just can’t find the time with two little terrors ruling my existence.
Shortest OAL you mean as the worst? 1.852 CBTO. 0.895MOA group
Just chose it because it’s the longest length of the lot. I don’t think it’s going to matter anyway.
Go with what you’ve suggested 1.852 as it’ll hopefully prove a point to some.
My worst fears, Gimp is going to shoot out what is possibly a "once in a lifetime" barrel just testing shit . . .
The sacrifices I make, for the benefit of the community...Quote:
Originally Posted by Tentman
you should all chip in 10 bucks for my next barrel
I am interested in doing the best I can to test the truth of the matter.Quote:
Originally Posted by McNotty
at present the average 3-shot group with 24.5gr 2206H (across different seating depths) is 0.6MOA
the smallest is 60% smaller than the average
the largest is 45% larger than the average
my current understanding is that with any particular load, you would expect + or - 60-70% variation in 3-shot group sizes. So what I'm seeing with the "tuning" of different seating depths is within the normal variation expected of any load. But I am very interested to do my best to test the process as so many people believe in it.
The current 21-shot group has a mean radius of 0.088 MRAD (0.88cm) and a predicted O95 of 0.37MRAD. The current observed (overlaid) 21-shot group size is 1.09 MOA (0.32MRAD).
If tuning works - a 20 shot group of the "best" load will have a smaller mean radius and a smaller observed group size over 20rd (overlaid) than the "worst" load.
If tuning doesn't work - both loads will be similar (within say + or - 20%) of each other for mean radius (more powerful) first and observed group size second (more variable), and also similar to the current overlaid 21rd group (although they should both be better than a group with 0.021" variation in seating depths - that's not consistency...)
All current shots fall within the same general "scatter"
does it get tighter with the selection of a specific seating depth that produced a better group in testing? We will find out.
Attachment 271820
This figure comes from hornady -Quote:
Originally Posted by gimp
Attachment 271822
And it is consistent with my observed results - for example https://www.nzhuntingandshooting.co....3/#post1656779
With the factory ammo that shoots around 3.5MOA out of my rifle, 10x 3-shot group sizes showed a variation of + or - 60-70% from the average group size.
Speaking from experience, I would have thought the correct answer to be - use up the remaining components, while making minor yet arbitrary changes to different variables.Quote:
Originally Posted by gimp
Then take a photo of the best three shot group, and post with a title to the effect of "load development nailed, off hunting!".
Cool to see some results, although I would have picked the charge with the lower es and ok on both sides, 25.1g�� As for the seating depth nice to see the changes in such small variations��
To be clear the "changes" visible in 3 shot groups are within the variation that happens within 3 shot groups of a single load. At present there is no evidence at all of any difference between the seating depths. SD is meaningless for a sample of less than 10 at minimum, more like 20-30. I've loaded 20 of each and I'll shoot tomorrow or Saturday and post results.
Okay so I went and shot these this morning. Conditions were good - essentially nil wind, my usual setup shooting at 100m with Atlas bipod & rear bag prone.
First, I did the process @McNotty suggested - 2x 3rd groups, and a 4rd group. Here are the results -
Attachment 272041
1.861 ("best" load identified) - produced groups of
3rd 1: 0.57 MOA
3rd 2: 0.79 MOA
4rd: 0.55 MOA
Mean radius from these 10 shots overlaid was 0.101MRAD and a 10rd aggregate group size of 0.79MOA. Looked pretty good.
1.852 ("worst" load identified - produced groups of
3rd 1: 0.85 MOA
3rd 2: 0.54 MOA
4rd: 0.89MOA
Mean radius from these 10 shots overlaid was 0.099MRAD and a 10rd aggregate group size of 1.21MOA. Looked ... actually basically identical to the 1.861 load if you look at MR rather than group size. The individual groups weren't obviously different either.
So then a 10rd group of each. Looked like this. This looks like a really bad group with the "better" load - the 1.861 CBTO. However bear with me through the results.
Attachment 272042
Best load 10rd group size - 1.37 MOA
worst load 10rd group size - 0.92 MOA
So what do the 20rd from each load look like when aggregated to one big 20rd group ?
1.861:
Attachment 272043
Mean radius: 0.116MRAD group size 1.37MOA (4cm). The predicted O95 from the 20rd mean radius is 4.8CM so the group size measured falls within expectations. This is a worse group than I "expected" but it is within the calculated expectations of all the data. Did I fuck it up and pull a couple of shots - change cheek pressure - did the wind gust a little bit L-R ? Who knows but it is what it is.
1.852:
Attachment 272044
Mean radius: 0.09MRAD, group size 1.21 MOA.
It does actually appear if you look at the MR, that either -
1. There is no functional difference between the loads and there is just a bit of natural variation due to measurement error etc showing up in the results
OR
2: I cannot shoot well enough to resolve any difference between these different loads, and the difference in the MR values is the "noise" from my shooter error
OR
3. The load identified as the "worst" through 3-shot group testing is actually slightly more consistent over large samples than the load identified as the "Best"
I do feel that I may have introduced a little error on the 10rd group of the 1.861 load and, had I not, it would have likely produced a more or less identical result to the 1.852. The variance in the mean radius is higher than you would expect from natural variation but there is likely a bit of measurement error here - the group analysis in the app isn't perfect. Regardless the results are functionally identical and fall within the cone of fire of the system even if a couple right at the edge were maybe contributed by a little extra shooter error.
Here's all 61 shots with this powder charge, and all seating depths - a 1.37MOA group with a mean radius of 0.096MRAD
Attachment 272045
So conclusion - with this rifle, bullet, brass, powder and shooter combination it is not possible to identify any difference in precision between loads with different seating depths by testing with 3 shot groups, at .003 inch increments of seating depth (as recommended by Erik Cortina, if he isn't the person to listen to for this then who is ?). Or 20rd groups of same.
All results fall within the cone of fire predicted by the 10rd mean radius for any of the 10 rd groups for any load.
Writeup is a bit messy and rushed because I'm off hunting for a week
Some further reflections -
1. I would not load this bullet in this rifle with this brass/powder. I now know this load does not meet my hit-probability requirements for precision (0.07MRAD mean radius or better, so that precision is not the limiting factor on 0.3MRAD targets).
2. I did not know that this load did not meet my requirements after 36 rounds of the conventional process. Often it is stated that "3 shot groups can't tell you how good something is, but they can tell you how bad it is and then you can rule it out". None of the 3-shot groups come close to representing the true size of the cone of fire and I could not rule the load out after 12x 3 shot groups. Clearly it was at least 0.895 MOA, as that was the largest 3-shot group - but that would meet requirements.
3. Nor did I know the true velocity consistency as measured by SD. 3-shot SDs/ES are useless to represent the true velocity consistency of a load.
I did not know enough to make a decision. A single 15-shot group of a single arbitrary load selected to be most likely to be functional would have given me much more useful information.
I am so glad fishing isn't this mind boggling. My brain would melt if I had to collect and interpret this kind of data for my lure making. Not that I am making any at the moment. Which reminds me, @gimp your lure is about an hours worth of work from being finished, been like that for about 12 months :D
Fortunely I've done it for you! No need. Life is simple, pick a good powder from ADI, a quality bullet, put it in good brass with a near max load seated to just short of mag length or something like 30 thou off the lands, whichever makes sense, shoot 10-15 of them, if it shoots good enough for you it's good, adjust speed and pressure as required, get a different bullet if it isn't good. Oh and start with a cut rifled match barrel bedded in a good stock if you want a good chance of actual sub-MOA precision
Keen as to get out on some kingis.... springtime is top water time...
Here's a 10 shot group from my 7mm08 at 100m off a bench rest.
1 cm grid.
Looks like the barrel's shot out ?
Attachment 272899
Returning to Gimp's first post in this thread:
I suggest a simpler and more efficient approach -
1. Define your requirements - what level of precision and velocity do you require? This requires sensible calibration of expectations - chasing smaller groups than most rifles can produce, and more speed than your chosen cartridge can generally produce, is perhaps not well-aligned to reality. Book max speed minus 15-50fps per inch for your actual barrel length is perhaps a good indicator of a realistic expectation for speed.
2. Select the most appopriate powder and bullet based on reasonably wide research, using good quality components
3. Load 10rd at a powder charge (within book data) that you predict will give the velocity target you'd like. It will be easier to be more precise in this estimate with more modern cartridges with lower variability in data. I suggest using more modern cartridges.
4. Load your COAL to be seated off the lands somewhere, and fit in your magazine. Forget about it.
4. Shoot to test
5. If velocity is in your target range, and precision meets your requirements, you are done.
So 35mm spread of centers (sorry, I haven't got the sd radius which would as @gimp says be a more reliable measure) predicts 70mm at 200m and 100mm at 300m which should leave enough margin for my own quite considerable aiming and wind estimating errors. I'd like a more flattering group but in fact it does meet my hunting requirements. I've previously debated whether the ft.lb number at 300m is good enough but suppose it is, then this load does actually meet velocity requirements too. Interestingly, 35mm for 10 shots was said to be equivalent to maybe 30% less (26mm) for 5 shots (post #171 on p 11 here) which is the manufacturer's accuracy guarantee when new. In practice, i haven't had a 5 shot moa group for a while.
I do a charge weight ladder mainly to demonstrate that 0.5 gr above my routine load is safe. I'm liking the idea of checking just a single load with 10 shots and I fully agree with Gimp that its very unlikely you can distinguish differences in precision with 5 shot groups. 10 shots loaded and fired on one day is way cheaper than returning two or three times to the range to refine my load.
I do use 5 shots is for defining group centre and adjusting zero, and don't go chasing the last 0.1 mRad. It's another story to prove it mathematically, but my rule of thumb is that if the point of aim is inside the circle of a 5 shot group, that's as good as you can get. The apparent centre wanders 0.1 or 0.2 mRad from one group to the next.
Just done a quick load development in a howa mini and was quite happy with the results, had to break up the groups as the mirage was a bit of an issue.
Checked length to refiling and dropped back 2mm to suit ease of mag feeding.
Started .5 grain above minimum and .5 grain increase until 25.5gr. 26gr was max in the adi for 69gr sierra hpbt and I am using 69gr targex. Loaded 12 rounds at 25.5 worked up looking for pressure, one over the chronograph and the last 10 into a group (would have liked to put them all over the chronograph but it was in use) mirage became an issue at about 4 rounds so had to space the shots out. I also used this range session to mount a scope (used some sako factory ammo for sight in)
I don't have the app used above but looks about 19mm outer edge to outer edge at 50mm high at 100m.
Going to load up 30 or so to put in the safe ready to go hunting then have a play with the other new brass and see if I cam get the 80gr eldm to work. In the same rifle (although i think it will be too compressed to work in the mag)
Attachment 273557
That's a good shooting Howa. Is it in a factory stock? @c-dogQuote:
Originally Posted by c-dog
It's a Ken Henderson stock. I think it may have been @Dreamer old rifle which I purchased off @25/08 IMPQuote:
Originally Posted by gimp
Only taken out hunting for wallaby with factory ammo (sako stuff seems to shoot pretty good) but thinking I'll take it out looking for a deer now.
How long are your 80gr eldm seated out, I can go to about 62.5mm so will see what sort of velocity and accuracy I can get with the magazine limitation.
Attachment 273722
I'm at about 61mm OAL for the 80ELDM, my throat is shorter than I really thought. Next barrel I will get it throated a little longer
Ok, I thought it was going to be too far in the case, I've settled at 62mm so I'll see how it goes, from the research I've done it looks like the howa minis seem to stabilize them ok. I'll report back this evening.Quote:
Originally Posted by gimp
Testing done for the arvo about 56mm outside diamater 10 shot group with the 24gr charge. Looks like I will stick with the targex at this point, half tempted to get a box of 77smk. I've got 20x 80gr targex here that I can also do a test with. Apart from the different projectiles and powder all was the same rest brass etc (new brass checked to fit chamber and measure for trim length, give a visual then load) I had high hopes for the 80gr eldm as I have had good results in other calibers but doesn't look like it's ment to be in this rifle, (I may try again with 2206h) I've never done loads in this sequence before but it's fairly quick and to the point (3 shot groups could have had me fooled into thinking it was 1/2 moa load) ill try get better data with my next lot of testing (the lane with the chronograph setup is usually a bit busy)
Attachment 273753
The 80s the big group under the handloaders logo? My mini seems to hate the eld range with all 3 barrels.Quote:
Originally Posted by c-dog
Yea mate correct, I should have said. What are you running in yours? I've got a few 69gr targex if you want to try some of those. That's the group to the right, pretty happy with them.Quote:
Originally Posted by Stocky
Also did 3 shots without the suppressor and the were same height but 70mm to the left, more for my reference than anything. Are your three all 223? I like the look of the 6mm arc barreled action but then I'd have to muck around and fine another stock dies etc
2 howa barrels and and an aftermarket nz barrel I wont name yet all in 223.Quote:
Originally Posted by c-dog
The 69 targex always shot well and I think that was the magic load.Quote:
Originally Posted by c-dog
I can't remember if I tried 80grn Targex or not but they should shoot ok.
I never had any luck with the 80 ELDM in either of my rifles with 1-8 twist barrels.
Sent from my CPH2531 using Tapatalk
First off I’d like to say this is super interesting and “ good on ya “ for going to the effort to both conduct these tests and to document them so thoroughly :thumbsup:Quote:
Originally Posted by gimp
I’m doing some load development at the moment for my 6.5CM with Sierra 130gr TMK projectiles.
So my initial test is always for Powder charge weight ( using 2209 powder ) with the projectile approximately 45 thou off the lands . I use the word approximately because I have yet to use / find a method that is spot on accurate when measuring throat length .
Starting at 1.0 gr below Sierra’s listed max charge I loaded up 6 rounds of each powder charge going up in 0.5gr increments ending up 0.5gr over their recommended max .
I shot those rounds and experienced zero pressure signs , all shot acceptable groups ( below 25mm at 100 yrds ) with an apparent improvement as the charge weight increased . All of this means “ Diddly Squat “ in the grand scheme of things but I wanted to find my upper limit of safe powder charge .
Now I have just loaded up another batch of loads using my chosen powder charge but with a selection of different seating depths. I make 10 thou increases in CBTO length.
So now in theory I am going to test 45 thou / 35 thou / 25 thou / 15 thou jump to see if things tighten or loosen as the seating depth changes.
I can’t understand why anyone would F*#k around with 3 thou changes , maybe in the world of Benchrest / F Class , but not in the world of Hunting / Factory barrels.
This seating depth test is just to see if there is an obvious trend developing either good or bad and then and only then will I load a decent amount of the chosen brew and shoot multiple 10 shot groups .
Quote:
Originally Posted by Ground Control
Note I've tested larger jump increments as well, with a secant ogive bullet (following Berger method) - 0.040" steps. With that bullet, I have largely only fired 3 shot groups however none of the shots fall outside of what can be expected from the single 10 shot group I shot - happy to re-test any of them with a larger sample size but there's no indication that any of them are any different.
https://www.nzhuntingandshooting.co....ectile-113861/
I'd be really interested to see your results, if you were able to test the depth that you conclude is the worst- as well as the best - and see if there's any real difference that can be resolved
Well I shot those seating depth test rounds and the conclusion is ………
I need to get better at my shooting form and trigger skills :D
All shot very well ( 17mm / 15mm /18mm ) at 100 yrds with no outstanding best or worst when you take into account my shooting ability and low number of rounds ( 2 x 3 shot groups for each load , those measurements are an average of the two groups )
I’ve come to the conclusion lately that if your Rifle likes the bullet / powder combo it doesn’t matter much about the other stuff .
I’m just going to load up 50 rounds ( of the 15mm load , not because I strongly feel it’s better , but hey why not ) and zero the Rifle with 3 x 10 shot groups and go kill stuff with the other 20 .
I don’t shoot at distances greater than 300 yrds with this Rifle and trying to achieve a genuine 0.5 moa gun is a waste of time when with minimal development I’m confident that 10 round groups will be hovering around the 1 moa + or - a fraction with any of the combo’s tried already
Thanks for reporting back. Can you post the targets?Quote:
Originally Posted by Ground Control
I don't think it's terribly surprising - even if one is a believer in seating depth changing precision, the TMK is a tangent ogive bullet and not believed to be sensitive.
I've posted before that the order of effect size when changing variables, in my view, is something like this (gaps indicative of relative importance) :
Barrel quality (get a good barrel, properly chambered)
Bullet quality
Powder choice and how it interacts with specific bullet and barrel
Brass quality
--------unproven to be an effect-------------------
Any tuning of powder charge or seating depth
I'm not sure I believe there is such a thing as a genuine 0.5MOA rifle - using the definition of precision that refers to the full dispersion of the true cone of fire. I have yet to see any evidence that such a thing exists. Certainly in practical terms, the effect size of shooter error swamps rifle precision in the noise and no-one could actually take advantage of it in a hunting scenario
So given all that. Are we not back too looking for a rifle that constantly groups 3 or 5 shots together close too our desired POI?
A ammunition manufacturers dream.All this shooting science to waste ammunition on.Enjoy it guys,lols.
I didn’t keep the targets, but what I will do is take a few photos of the 10 shot groups that hopefully will be happening in the next week .Quote:
Originally Posted by gimp
How do I get one of those apps that everyone seems to be using to measure their groups and get the mean radius info etc ?
Hornady 4DOF app, pay $4 for group analysisQuote:
Originally Posted by Ground Control
Quote:
Originally Posted by whanahuia
If it actually does this, and you have actually checked meaningfully that it does this - you have collected a large sample size of data with reference to a fixed point.
This is what I recommend.
I just recommend doing it more efficiently so that you get the information immediately, and analysing it with a view to understanding whether it meets clearly set requirements or not.
I think the key as you say, is getting the best barrel/rifle combo you can afford. It's for most a moot point after that, as Id dare say most people can't go selling and buying if its not quite what they hoped for.
Taking extreme notice due too this thread, I have noticed a very slight bias towards the left of centre in my groups, and have moved 1 click right due to that. But reality is if as you say, human error is accounted for, it's in reality only a 4cm error at my self imposed max shooting distance. Hardly the factor that would be responsible for a bad hit.
Actually you would be better off with your zero 1 click (1/4moa or 0.1mil) left of center as the spin drift will be to the right and the bullet will be almost exactly center by 400m.Quote:
Originally Posted by whanahuia
So personally if it is 1 click left at 100m it is a perfect zero for my rifle setups.
