Bullet depth vs powder charge, which first?

[Clancy]

never change more than 1 variable at a time in when testing or it impossible to know which variable you changed contributed to a change in the test results

Respectfully, if you know what you’re doing, it’s not wrong at all.

Check out “Tony Boyer Load Development” on the google machine..... you can tell me I’m wrong all you want, but you’re going to argue with that success?

Nope? Ok thanks.

 

[Richard Coody]

Respectfully, if you know what you’re doing, it’s not wrong at all.

Check out “Tony Boyer Load Development” on the google machine..... you can tell me I’m wrong all you want, but you’re going to argue with that success?

Nope? Ok thanks.

well i guess i left out my typical caveat. i apologize

Whatever works for you. lots of ways to skin this cat.

 

[urbanrifleman]

Typical grid target. Charge is left to right going up .3 and seating depth are the rows.

In this case you can clearly see the trend.

 

[cw308]

I benchrest shoot only , I would start with the powder starting load with the listed OAL in the book .Seat the bullet to that OAL the measure the ogive , then only measure form ogive when changing for jump or jam , but first get a promising load the groups well . 3 five shot groups then 3 ten shot groups.

At that point I would work with that charge and change my bullet measurements . Do you know the measurement from base to lands ?
What rifle are you shooting an caliber ?
How are you sizing ,Full or Neck ?
Headspace measurements ?
For hunting or target?

 

[Richard Coody]

Typical grid target. Charge is left to right going up .3 and seating depth are the rows.

In this case you can clearly see the trend.

i believe i would do a little more exploring around 0.015.and 0.020 off and 29 to 29.3 gr

i see something there in that last row i often see in load.testing. a little horizontal then hit the node for 2 charges and then it starts to go vertical

 

[urbanrifleman]

i believe i would do a little more exploring around 0.015.and 0.020 off and 29 to 29.3 gr

i see something there in that last row i often see in load.testing. a little horizontal then hit the node for 2 charges and then it starts to go vertical

This is an early target. Later targets clearly showed that the seating depths close to touching shot the best with this bullet. At all speeds, which repeats over and over. There is a definite seating depth that shoots the best and the closer you get to it the smaller it shoots, no matter the powder charge.

Then you tune to the node. But you can do them simultaneously as shown in the grid target.

 

[urbanrifleman]

He is the node you want to find. Although you cannot read the right target value, it is 3308.

So, the left target and the right target have the same value with a slight hump in the middle. A true dead spot.

 

[Richard Coody]

This is an early target. Later targets clearly showed that the seating depths close to touching shot the best with this bullet. At all speeds, which repeats over and over. There is a definite seating depth that shoots the best and the closer you get to it the smaller it shoots, no matter the powder charge.

Then you tune to the node. But you can do them simultaneously as shown in the grid target.

if you are speaking of your first group in the first row it seems to have a very narrow charge node.

now i always start out with a hard jam and work out from there.

this is my little savage .005 off a hard jam with 105 hybrids. see my way works too!

9 8

 

[urbanrifleman]

if you are speaking of your first group in the first row it seems to have a very narrow charge node.

now i always start out with a hard jam and work out from there.

this is my little savage .005 off a hard jam with 105 hybrids. see my way works too!

9 8

One group really doesn't show it will stay in tune. The grid shows the range that it will stay in tune. Especially if you add velocities.

That is the trick. Staying in tune.

No, I was talking about the bottom row, where every group is on the average better no matter the charge.

 

[Richard Coody]

One group really doesn't show it will stay in tune. The grid shows the range that it will stay in tune. Especially if you add velocities.

That is the trick. Staying in tune.

No, I was talking about the bottom row, where every group is on the average better no matter the charge.

i like your bottom row as i said earlier. a node is in there somewhere.

 

[urbanrifleman]

i like your bottom row as i said earlier. a node is in there somewhere.

There are several nodes, but you will notice finding the right seating depth has made all of the groups good, the nodes are even better.

 

[hawkeyeshoooer]

I conduct my OCW tests with the bullet seated at the depth at which the ogive touches the lands. Theoretically, this is a neutral depth --- the bullet is neither jammed nor jumped. Once I determine the OCW, I then load (at the OCW) and shoot five 5-round groups seated at 0.010" jammed (always start jammed), 0.030" jumped, 0.060" jumped, 0.090" jumped, and 0.120" jumped. Usually, one of these groups will perform significantly better than the others. From there, I can further refine my seating depth until I get the desired results. This is what works for me.

 

[Puzzaz01]

Ok..... a picture is worth a thousand words. As you can see when I got down to a desired seating depth, (2nd row from bottom) 3 different powder charges ranging from 39.4 grains to 40.7 all shot nicely. That's the seating depth I'll start to tweek. Do you think I was lucky and hit three different perfect nodes, NO the test would have worked even if I would have went up or down a few tenths. Now keep in mind you must be using wind flags and have a barrel that's broke in and by all means be on your game.

 

[JFrank]

I conduct my OCW tests with the bullet seated at the depth at which the ogive touches the lands. Theoretically, this is a neutral depth --- the bullet is neither jammed nor jumped. Once I determine the OCW, I then load (at the OCW) and shoot five 5-round groups seated at 0.010" jammed (always start jammed), 0.030" jumped, 0.060" jumped, 0.090" jumped, and 0.120" jumped. Usually, one of these groups will perform significantly better than the others. From there, I can further refine my seating depth until I get the desired results. This is what works for me.

I like the process as well I use tangent ogive Bullets so my seating test is not that course
J

 

[powderbrake]

I conduct my OCW tests with the bullet seated at the depth at which the ogive touches the lands. Theoretically, this is a neutral depth --- the bullet is neither jammed nor jumped. .

I also start my load tests just touching the lands ( 0 point). After finding the best powder charge, I then adjust the seating, in and out with about .003 increments. I have yet to find a load that isn't better when it is in the lands.

Yes I know that a lot of people jump the bullet, particularly with the VLD hybrids, and their targets tell them that it is the place to be. I am not disputing that.

 

[urbanrifleman]

View attachment 1058355 Ok..... a picture is worth a thousand words. As you can see when I got down to a desired seating depth, (2nd row from bottom) 3 different powder charges ranging from 39.4 grains to 40.7 all shot nicely. That's the seating depth I'll start to tweek. Do you think I was lucky and hit three different perfect nodes, NO the test would have worked even if I would have went up or down a few tenths. Now keep in mind you must be using wind flags and have a barrel that's broke in and by all means be on your game.

Yes. That is it.

 

[ClassCat]

View attachment 1058355 Ok..... a picture is worth a thousand words. As you can see when I got down to a desired seating depth, (2nd row from bottom) 3 different powder charges ranging from 39.4 grains to 40.7 all shot nicely. That's the seating depth I'll start to tweek. Do you think I was lucky and hit three different perfect nodes, NO the test would have worked even if I would have went up or down a few tenths. Now keep in mind you must be using wind flags and have a barrel that's broke in and by all means be on your game.

Nice. What is the Jam ?

 

[JimSC]

Respectfully, if you know what you’re doing, it’s not wrong at all.

Check out “Tony Boyer Load Development” on the google machine..... you can tell me I’m wrong all you want, but you’re going to argue with that success?

Nope? Ok thanks.

I have Boyer's book on Rifle Accuracy and have read it cover to cover then reread certain chapters such as chapter 22 several times but I use a scientific method when doing load development.

I was trained that if you change more than one variable at a time in any scientific experiment and a change takes place during an experiment you do not know which variable caused the change or if it was a combination of changes. Making more than one change at a time could even mask a change that by itself could result in a improvement but the improvement could be canceled out by the negative effects of the other change and you will never see it.

You do what works for you and I will do what works for me, there is no need for a argument.

edit- One thing I have noticed since I joined this forum is is that BR shooters, F class shooters and Precision Rifle competitors all strive for accuracy, but have different ways of measuring success and paths to get there

 

[Toby Bradshaw]

I have Boyer's book on Rifle Accuracy and have read it cover to cover then reread certain chapters such as chapter 22 several times but I use a scientific method when doing load development.

I was trained that if you change more than one variable at a time in any scientific experiment and a change takes place during an experiment you do not know which variable caused the change or if it was a combination of changes. Making more than one change at a time could even mask a change that by itself could result in a improvement but the improvement could be canceled out by the negative effects of the other change and you will never see it.

The Boyer charge x seating depth matrix is a perfectly valid scientific experiment -- a 2x2 factorial experiment, to be precise. Factorial experiments are required when the interaction between variables has a significant effect, as does the interaction between charge and seating depth.

 

[JimSC]

The Boyer charge x seating depth matrix is a perfectly valid scientific experiment -- a 2x2 factorial experiment, to be precise. Factorial experiments are required when the interaction between variables has a significant effect, as does the interaction between charge and seating depth.

major edit - I think the light just came on. What you guys are doing is using the Boyer method as step 1 such as the one in post #33 then fine tuning the best group from the test with a ladder style test looking for a flat velocity node and perhaps even tweaking the seating depth even finer. Or am I still missing something?