High Group Variance within a Ladder Test
- Thread starter PrairieHunter
- Start date
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memtbThis what you are looking for? You can scroll to the last minute or so to see the final results.
I think I would go back and try 2.977, 2.980, 2.983, and 2.986 just for fun.
willfrye027
Well-Known Member
I do 100 yards for load development and then just hammer steel from 500-1000 for the next 100 or so rounds. Only once, I felt like things were starting to fall apart at distance about half way through that 100 round trial period. I went back to 100, groups had opened up..was seeing pressure signs and needed to drop charge weight. I don't personally believe in rifles needing a tune at long distance..but I'm also not shooting LR benchrest or F class where an inch or two at 1000 makes a difference.
Not saying my way is the best either, or that I'll never change…but it's certainly working well for me.
willfrye027
Well-Known Member
I'll have to watch more closely to see how they controlled the variables. Eyeballing the results it would need to be repeated to have statistical validity; the difference between the groups is not large enough.
Huge variable that cannot be controlled are the environmental conditions changing between those two strings.
things done with 100s of rounds, in accuracy fixtures, in wind tunnels…that is the data I can get behind.
FireFlyFishing
Well-Known Member
Below are some targets from my last couple of range sessions. Rifle is a new Tikka CTR .308. This photo is factory Hornady 150 SST ammo I had laying around that I thought I'd throw down the pipe first as I didn't have any test loads developed and I wanted to get some rounds through it first anyways. 10 shot group. Not bad for a new rifle and factory ammo.
Below is a 5, yes, 5 shot group derived from the ladder accuracy node method. I think I can do better than this so testing is ongoing. I have another 5 rounds of this exact load I will be shooting with others to verify. I'm waiting for weather to clear to resume testing. This group measured 0.540" CTC.
I'm happy with this honestly and I have something to fall back on if my next trial groups don't pan out.
I could have made groups of 20 rounds or 50 rounds or whatever. I gotta feed my kids too. My gut is telling me when I take this rifle hunting and taking shots of no more than 600ish (it is a .308 after all) I'm feeling pretty good with my chances hitting an animal….accurately.
Amen on the chronograph referrals. I don't shoot without one now, except huntin.
It can offer a lot of answers.
Sometimes there is a reason flyers fly!
And the reason I do load development at 300 is because many times, on custom or factory rifles and loads, I've seen 100 look awfully promising only to see it blow up 2-3x as much as it "should" on further down the line. I feel better having 1.5" or less groups at 300 than I do .5" or less at 100, when I call it good, in whatever the environmental conditions are on a given day.
It can offer a lot of answers.
Sometimes there is a reason flyers fly!
And the reason I do load development at 300 is because many times, on custom or factory rifles and loads, I've seen 100 look awfully promising only to see it blow up 2-3x as much as it "should" on further down the line. I feel better having 1.5" or less groups at 300 than I do .5" or less at 100, when I call it good, in whatever the environmental conditions are on a given day.
willfrye027
Well-Known Member
That looks great to me! The chance of that 5 round group looking bad on repeat is lower than a 3 round group. And the smaller the group, better odds that a large group will be acceptable.
I took a screenshot from Hornadys article on this for a helpful chart
For accurate data, sample size matters.
How many shots do you need to determine the accuracy of your rifle?
blog.hornady.com
FireFlyFishing
Well-Known Member
That looks great to me! The chance of that 5 round group looking bad on repeat is lower than a 3 round group. And the smaller the group, better odds that a large group will be acceptable.
I took a screenshot from Hornadys article on this for a helpful chart
View attachment 556202
For accurate data, sample size matters.
How many shots do you need to determine the accuracy of your rifle?
"Strike the right balance"
Indeed.
Ackley Man
Well-Known Member
Tell the guys that are in the BR Hall of Fame that node is a fairy tale.
Ackley Man
Well-Known Member
Seating distance + or - from the lands, neck tension and lastly knowing how to read group dispursion in relationship to powder charge. As a side note we have fround that as a general rule the maximum (-) node rarily exceeds .006.
Obviously VLD bullets are a different story.
Obviously VLD bullets are a different story.
Sounds like barrel was brand new or it was needing cleaned. Or both.
