Help needed with load development

Mc Fraser

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Jul 23, 2018
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Hello,

I need advice on the following test results.
Background: all rounds where loaded with the same amount of powder; the difference is in distance to lands; the brass used to shoot on the white targets was FL seized with a neck tension of ~3 thou while the shots from the black targets where neck sized only with ~1 thou neck tension. The bullets for 1 & 5, 2 & 6, 3 & 7 and 4 & 8 are loaded with the same die setting, however, there is a slight difference in measured CBTO, neck sized ones tend to let the bullet seat deeper. There was an 11 mph wind from SW if N is facing the target.
What would you do next, assuming the velocity test was done and a nice node was found?
The rifle is a factory Tikka in 270 Win. Assuming I’m happy with the results which group/groups would you chose for hunting? Would you tinker with it? How?
TIA.
 

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nksmfamjp

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1&5 look like the same group that you were just off a bit in windage for #1. Also, it looks like you shoot the black bullseye better, unless the wind changed at the same time as the color change.
 

Jud96

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In my opinion, I would drop the neck sizing completely. Stick with full length sizing and bump your shoulders .001-.003 for easy chambering and bolt closing. Next, find where this particular bullet touches the lands. You need a reference point. When you find that, load 3 rounds each at .020 off the lands and keep seating the further off in .005 increments. I would have them setup from .020 off to .080 off and go test them. It’s a lot of shooting, but it will payoff by showing you exactly where your rifle and bullet combo shoot best.
 

Mc Fraser

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In my opinion, I would drop the neck sizing completely. Stick with full length sizing and bump your shoulders .001-.003 for easy chambering and bolt closing. Next, find where this particular bullet touches the lands. You need a reference point. When you find that, load 3 rounds each at .020 off the lands and keep seating the further off in .005 increments. I would have them setup from .020 off to .080 off and go test them. It’s a lot of shooting, but it will payoff by showing you exactly where your rifle and bullet combo shoot best.
That's what I did here, an attempt to find a distance to lands node.

1&5 look like the same group that you were just off a bit in windage for #1. Also, it looks like you shoot the black bullseye better, unless the wind changed at the same time as the color change.
Thanks. What do you think about #5. To me looks like a great group, 2976 average fps, single-digit ES and SD. Same as #3?
 

Jud96

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I understand you made an attempt to find your seating depth. What I’m saying is to use a more refined way of doing it. It’s hard to interpret data when multiple variables are changing (neck sizing vs full length sizing and neck tension). Also you didn’t list what your actual bullet jumps or CBTO measurements are, so it’s impossible to know how much you’re adjusting each set of test loads. I’m just trying to get a better understanding of what you have done so far and I’m trying to help you find more conclusive data.

All of your groups except Group #4 show some sort of horizontal stringing. This indicates you’re not on a good seating depth node. You need to adjust in finer increments and you’ll start to see the groups come closer and closer together as you get in a seating depth node.
 
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Mc Fraser

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I understand you made an attempt to find your seating depth. What I’m saying is to use a more refined way of doing it. It’s hard to interpret data when multiple variables are changing (neck sizing vs full length sizing and neck tension). Also you didn’t list what your actual bullet jumps or CBTO measurements are, so it’s impossible to know how much you’re adjusting each set of test loads. I’m just trying to get a better understanding of what you have done so far and I’m trying to help you find more conclusive data.

All of your groups except Group #4 show some sort of horizontal stringing. This indicates you’re not on a good seating depth node. You need to adjust in finer increments and you’ll start to see the groups come closer and closer together as you get in a seating depth node.
Thank you. I'll take a picture of my written notes as well, which will add more information to the story.
You made an interesting comment that I start to understand but I was hoping that you can elaborate it a bit more
All of your groups except Group #4 show some sort of horizontal stringing. This indicates you’re not on a good seating depth node. You need to adjust in finer increments and you’ll start to see the groups come closer and closer together as you get in a seating depth node.
I would like to know more about vertical horizontal and vertical stringing .... perhaps you could recommend a good read? I will google it myself too.
Thanks again.
 

Jud96

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Thank you. I'll take a picture of my written notes as well, which will add more information to the story.
You made an interesting comment that I start to understand but I was hoping that you can elaborate it a bit more
All of your groups except Group #4 show some sort of horizontal stringing. This indicates you’re not on a good seating depth node. You need to adjust in finer increments and you’ll start to see the groups come closer and closer together as you get in a seating depth node.
I would like to know more about vertical horizontal and vertical stringing .... perhaps you could recommend a good read? I will google it myself too.
Thanks again.
From my personal experience that’s what I have discovered. I have heard others say the same but I don’t have any links to share. I will share this target with you though that shows the type of patterns I’m talking about. You can see how the groups go from vertical then horizontal then to little groups. This was with my Remington 700 ADL Varmint chambered in .243 Win using 87gr VMAXs. Everything about the loads were identical other than the seating depth changing.
ACE3926D-38CC-40E2-8C20-01BD99542754.jpeg
 

C-Crist276

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Jun 18, 2020
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San Jose
Hello,

I need advice on the following test results.
Background: all rounds where loaded with the same amount of powder; the difference is in distance to lands; the brass used to shoot on the white targets was FL seized with a neck tension of ~3 thou while the shots from the black targets where neck sized only with ~1 thou neck tension. The bullets for 1 & 5, 2 & 6, 3 & 7 and 4 & 8 are loaded with the same die setting, however, there is a slight difference in measured CBTO, neck sized ones tend to let the bullet seat deeper. There was an 11 mph wind from SW if N is facing the target.
What would you do next, assuming the velocity test was done and a nice node was found?
The rifle is a factory Tikka in 270 Win. Assuming I’m happy with the results which group/groups would you chose for hunting? Would you tinker with it? How?
TIA.
4 or 5
 

rsnell

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Oct 24, 2014
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69
You can find the OAL to lands using the Hornady or Sinclair OAL measuring gauge.
 

misterc01

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Feb 15, 2019
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Florida Panhandle
Three of the bullets I use I am finally getting around to more precise seating depth tests. I have a good idea of where to start with them and have five rounds loaded for each for testing, at three different depths for a total of 45 rounds. I decided I want to try some Bergers as well, adding another more rounds, but from what I have been reading, Bergers perfom best either seated on the lands or a ways (.080) out. Not wanting to find a good depth and wear out the barrel doign it, any advice on a seating depth test strategy to zero in (pun not intended) on the best depth with a minimum number of rounds?
 

Jud96

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Three of the bullets I use I am finally getting around to more precise seating depth tests. I have a good idea of where to start with them and have five rounds loaded for each for testing, at three different depths for a total of 45 rounds. I decided I want to try some Bergers as well, adding another more rounds, but from what I have been reading, Bergers perfom best either seated on the lands or a ways (.080) out. Not wanting to find a good depth and wear out the barrel doign it, any advice on a seating depth test strategy to zero in (pun not intended) on the best depth with a minimum number of rounds?
I start .020 off and work back in either .005 or .010 increments and load 3 rounds at each depth and shoot groups. If you want to get a rough idea then shoot .010 increments. If you want to really narrow in, then shoot .005 increments. I wouldn’t get carried away loading up a ton of ammo. I would go from say .020 off to .060 off and go shoot groups. If you find a good group somewhere in that jump range then repeat it and load up 3 rounds that’s .003-.005 longer and 3 that are .003-.005 shorter and go see which shoots best. Pick the best one and run with it.
 

DUSTY NOGGIN

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salt lake city
what is your distance ...

make sure you understand how to adjust your scopes paralax before any load development if your scope doesnt have an AO adjustable objective or a side paralax knob .. you could just be wasting components and just creating yourself confusion


this is my plan that i use to get a usually decent base line to work from ,

first , (velocity/ max pressure) combination test (24 shots) , from max load down in 0.2 grain increments , shoot with a crono , LR , or mag- neato -speedometer

once you find an acceptable ES/SD , do a seating test with that powder charge , with 24 rounds like @Jud96 did above ( i usually only do 12 or 16) then use the rest of the 50 to fine tune the seating

you should have found something decent in this process that you can work with . but you have to keep prepping brass and seating to these specs , so when you do minor changes and tweeks , you can see the difference
 

A7-NW

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I would retest starting at mag length and then move in at .005 increments until you find the node. Here is my 2nd seating depth test this last weekend. 100 yards is all that is needed. You will need 3 rounds each of the same load keeping everything as consistent as possible and measuring your base to ojive for Accuracy. COL does not work for this test it must be the ojive measurement. This is my target rifle in 300 RUM and it likes .010 off the lands. .150 is the lands in the photo.
You can initially start at .001 and move in at .020 if you are single round feeding to identify the nodes, once found you can retest in smaller increments. I found this rifle shoots as good at .010 as it does at .138 if I want to mag feed it but is not a hunting rifle. The last on the right is the zero, top shot first round. I reset and bottom 2 are adjusted.
Good luck.
 

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misterc01

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Florida Panhandle
As soon as the Hurricane has passed and wind died down, I will load up then and head to the range. Plan is to shoot at 300 yards, with chronograph. Scope has a parallax adjustment. Based on others comments on Berger's liking close to lands, how does three rounds each: .010 off, then .20, .40, .080, finish at .120 off. Take the one(s) that show the best promise, try .05 +/- , then .10 +/_? Should a get a total round count under 40 that way. Thoughts?
 

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