If your monster magnum shoots that good with 0.25 jump, why worry about 0.0005?
Seating depth variation
- Thread starter nksmfamjp
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This will be a hard pill to swallow for many, as our personal opinions on reloading are as deeply held as many religious beliefs. I was in the same camp as everyone on this thread, fussing over seating depth. Having an engineering and medical background I approach reloading from a science based perspective. I have never been able to understand or reconcile the fact that there are so many various reloading techniques that all produce sub quarter MOA results. Everyone claims their particular technique is the best way to make small groups. But from a scientific perspective, if 4 or 5 different reloading processes produce identical results, then the process itself can't be as critical to the end result as we think. So which steps in the loading process truly affect group size?
I recently read the following article and then listened to Hornady Podcasts #50 and #52 and the answer to the question became crystal clear. I no longer worry about seating depth. What you see in 3 to 5 shot group sizes is statistically invalid, nothing but noise and not a reliable judge of what your rifle is truly doing.
Rifle Nodes: How You’ve Been Wasting Your Time and Money on Load Development
Everything you know about rifle nodes and load development might be wrong. Click here to see the results for yourself.www.outdoorlife.com
Hornady can say anything they please. And they Do.
I'll be listening to the consistent results I get on paper, steel and live targets time after time and year after year, and I won't forget the real results.
Guess I'm just " lucky"?
I'll be listening to the consistent results I get on paper, steel and live targets time after time and year after year, and I won't forget the real results.
Guess I'm just " lucky"?
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With the Wbees I don't. Just load to mag length.
rogerstv
Well-Known Member
I do this too. I measure every bullet. Only those at the proper CBTO go in the ammo box. All others are adjusted until they match. A quality seating die produces repeatable results. Always an outlier or two which is why I measure every one. It's one of the variables I can control.
The only thing Weatherby got right was high velocity with acceptable pressure. And that was the goal.
Precision was not, is not, and never will be associated with the long free-bore design, hugely over-bore cases and screaming velocity. Freaks do exist, a tiny percentage of the total.
VenatusDominus
Well-Known Member
I don't think you are lucky, I think you have found, through testing, a powder/bullet combo that shoots well in your rifle. What the statistics show, from large sample sizes, is "that changes in seating depth, like charge weight, didn't result in any meaningful changes in accuracy" across large group sizes, and the accuracy changes you are seeing across small sample sizes are not representative of what the rifle is really doing.
Tyler Freel from OutdoorLife has no affiliation with Hornady and confirmed their science with his own independent study. That is how we do things in the world of science. We study a problem and publish our findings so that others can independently prove or disprove the accuracy (pun intended) of our results.
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Here's the good news. If the amount of jump, for the most part, doesn't matter, then everyone is right. We'll all think we have the magic formula. And in a way we'll be right. But we may have wasted resources that could have been better spent elsewhere.
If monster bees shoot beyond great at whatever jump, then most everything will work, 0.25 or 0.025. It's extremely difficult to shoot 0.5 moa at 1,000 yards with a heavy target rifle and mild chamberings much less a monster hunting rifle.
If monster bees shoot beyond great at whatever jump, then most everything will work, 0.25 or 0.025. It's extremely difficult to shoot 0.5 moa at 1,000 yards with a heavy target rifle and mild chamberings much less a monster hunting rifle.
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If depth doesn't matter, how do I predictably change the shape of groups with seating depth adjustments?
That goes for all my rifles.
Not the last one I tinkered with
I've never strived for adjustments lessthan .003 at a time.
That might change with better equipment though.
That goes for all my rifles.
Not the last one I tinkered with
I've never strived for adjustments lessthan .003 at a time.
That might change with better equipment though.
VenatusDominus
Well-Known Member
If you shoot larger samples sizes, 20-30, you will see that the group shape is not changing. Small sample size group (3-5 shot) shape changes are just random bullet dispersions within the cone of fire. It is all laid out in the studies I posted and makes perfect sense when you think about it.If depth doesn't matter, how do I predictably change the shape of groups with seating depth adjustments?
That goes for all my rifles.
Not the last one I tinkered with
I've never strived for adjustments lessthan .003 at a time.
That might change with better equipment though.
I am not saying that your method of reloading doesn't produce results. It obviously works for you, without dispute. What I am saying is that it may not work for the reasons you believe, and that there may be an easier way to get the same accuracy results with a lot less work. I assume your time and resources are valuable to you, I know that mine are. If I can get the same results with fewer steps and less work, then I am all for that. For me, the way to do that is to science the @#$% out of it. I am simply trying to share some real world, science based information that, while it goes against some long held dogma in reloading, has been proven through the scientific method and may save you some time and resources.
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birddog 68
Well-Known Member
It's interesting that Berger recommends doing a seating depth test when from what I have read here it really doesn't matter.
I have been using the Berger method with most bullets nowadays and I have seen the results and I believe results.
As far as science goes, I have a hard time believing MOST so called scientists. Most seem to be pushing a agenda instead of actual science. JMO
I have been using the Berger method with most bullets nowadays and I have seen the results and I believe results.
As far as science goes, I have a hard time believing MOST so called scientists. Most seem to be pushing a agenda instead of actual science. JMO
I trust SMEs/ballisticians like Litz/Berger. I am no expert or claim to be one, but I have nearly five decades of experience in which seating depths mattered in my load developments.
VenatusDominus
Well-Known Member
In the two podcasts I referenced, the Hornady engineers/ballisticians are not pushing any specific products or components. They collected the data using their projectiles and those of their competitors. From what I observed there was no underlying agenda other than to educate the shooting community. They freely admit that by using the methods discussed you will shoot less of their components in load development, not more.
The Hornady engineers do state that for some bullets with very long ogives (which could include Berger Bullets) and/or some custom throats, seating depth may have more of an effect on accuracy. However in the 1000s of data points they have recorded, seating depth has not shown to have any statistically meaningful difference in accuracy. Obviously seating at the lands will affect pressure and therefore velocity, so that is not what they are talking about. But seating at .02" vs .04" "off the lands" demonstrated no statistical difference in accuracy over large sample sizes and that the changes noted in small sample sizes were just the result of random bullet dispersion within the cone of fire of the particular rifle. The only way to be sure is to shoot a large enough group size.
The recommendation is to shoot group sizes for your particular application, so for a hunting rifle with a thin barrel, shot 10 groups of three, letting the barrel completely cool between groups. Then measure their x and y distance from the point of aim and combine all 30 shots on one plot. There are apps that let you take a picture of several groups and it will do the combining for you. If you are shooting a PRS or F-class rifle then maybe you shoot three groups of 10 and then combine them.
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Science ? How about 6 years of actual shooting in a controlled 350 yd warehouse precisely measuring the effects of reloading methods over tens of thousands of rounds? The cliff notes: " if you change the bullet seating depth or the grip on the bullet, you're going to see bad things happen fast."
precisionrifleblog.com
Secrets of the Houston Warehouse – Lessons In Extreme Rifle Accuracy
Back in 1993, Precision Shooting Magazine printed a landmark article about the findings of a group o...
