Deciphering ladder and next steps

[The Oregonian]

Did essentially my first ladder today and still learning on load development. I am following the process of the ladder testing article by Jim Baney pinned above on this board. He doesn't really cover seating as he knows the seating for his load already.

Here are the results from three ladders at 500 yds...same loads on each ladder. I did a pressure test last time and got pressure around 61.7 or so, so I backed up from there to 61.4 and worked down by .4 grains. I used .020 off for all.

Picture below has all the details, but summary is that shots 2-5 had vertical of .6", .6", and 1.5" in the three ladders. This covers 59.8 gr to 61.0 gr and covers avg velocity of 2919 to 2984. Somewhat surprised that the vertical was very similar for 65 fps difference in high and low avg, but the results are what they are.

Would you work between 2 and 3 (avg velocities of 2919 and 2931) or 4 and 5 (avg velocities of 2964 and 2984)? Those two had closer velocities to each other....or would you go smack in the middle of 2 and 5 (avg velocities of 2919 and 2984? Advantages of between 2 and 3 or 4 and 5 are closer velocities but advantage of going between 2 and 5 is a much wider node. I'm not concerned with getting max velocity and more focused on best accuracy.

And seating depth should be tested and whatever charges I move forward with. Should I do seating next on a single charge? Or refine the charges first and then do seating?

Many thanks.



Starting conditions - 67*, 73%, 29.95 and ended at 71*, 63% and 29.97.

Loads
1 - 59.4
2 - 59.8
3 - 60.2
4 - 60.6
5 - 61.0
6 - 61.4

 

[ar10ar15man]

personally i think it a waste of time and money to do three ladders instead of just doing three shot groups, if you are gonna shot three times.
a ladder is to find nodes...not groups. now you confuse yourself by trying to figure out a node while looking at vertical in GROUPS.
i would go shoot a 3 or 5 shot group of load 3 and 5

 

[The Oregonian]

I'm looking for a node by looking at vertical spread of various shots. And did it three times based on the article i mentioned. I'm not looking at it in groups, I'm looking at the powder charges and how much vertical there is.

 

[Mikecr]

Seating 1st, then ladder

 

[ShtrRdy]

Since shots 3, 4, 5 had very little vertical in all three cases I would investigate the recipe for shot 4 further.

 

[The Oregonian]

Since shots 3, 4, 5 had very little vertical in all three cases I would investigate the recipe for shot 4 further.

Thanks...does the jump in velocity from 3 to 4 concern you or should I just trust where the shots landed more than the chrono? In case it helps, my hunting will be 600 and in, and i practice 500 to 750 predominantly, so while vertical due to that velocity gap may show up more at 1000, that is not a significant concern for me right now.

Thx

 

[ar10ar15man]

it looks like over 4" vertical in 3 shots on three targets of load 4...
had load 4 been shot all at one time we might have useful data. as it is, clearly target 3 is no where near target one....the problem with multiple "ladders"...conditions change

 

[Alex Wheeler]

Load between 4 and 5 then work your seating depth. Put those 168s in the lands, I have never tuned a rifle that shot its best jumping past .010".

 

[BountyHunter]

Work loads around 2 and 3, notice the big jump in MV from 3-4, you are moving out of the node. 2 and 3 are very close in MV in all three tests. That is in the node

 

[parshal]

I would shoot a few groups with 60.8, between load 4 and 5 simply due to the low SD. I'd want to see if that SD stays that low and how it groups. For BountyHunter, is that not a "node"?

 

[Almondgrower]

What rifle are you shooting?

 

[Saracen]

personally i think it a waste of time and money to do three ladders instead of just doing three shot groups, if you are gonna shot three times.
a ladder is to find nodes...not groups. now you confuse yourself by trying to figure out a node while looking at vertical in GROUPS.
i would go shoot a 3 or 5 shot group of load 3 and 5

Shoot groups, not ladder. If you can shoot a ladder, you can shoot a group.

 

[Saracen]

Did essentially my first ladder today and still learning on load development. I am following the process of the ladder testing article by Jim Baney pinned above on this board. He doesn't really cover seating as he knows the seating for his load already.

Here are the results from three ladders at 500 yds...same loads on each ladder. I did a pressure test last time and got pressure around 61.7 or so, so I backed up from there to 61.4 and worked down by .4 grains. I used .020 off for all.

Picture below has all the details, but summary is that shots 2-5 had vertical of .6", .6", and 1.5" in the three ladders. This covers 59.8 gr to 61.0 gr and covers avg velocity of 2919 to 2984. Somewhat surprised that the vertical was very similar for 65 fps difference in high and low avg, but the results are what they are.

Would you work between 2 and 3 (avg velocities of 2919 and 2931) or 4 and 5 (avg velocities of 2964 and 2984)? Those two had closer velocities to each other....or would you go smack in the middle of 2 and 5 (avg velocities of 2919 and 2984? Advantages of between 2 and 3 or 4 and 5 are closer velocities but advantage of going between 2 and 5 is a much wider node. I'm not concerned with getting max velocity and more focused on best accuracy.

And seating depth should be tested and whatever charges I move forward with. Should I do seating next on a single charge? Or refine the charges first and then do seating?

Many thanks.



Starting conditions - 67*, 73%, 29.95 and ended at 71*, 63% and 29.97.

Loads
1 - 59.4
2 - 59.8
3 - 60.2
4 - 60.6
5 - 61.0
6 - 61.4

View attachment 136487

I'm sure I'll catch flak for this, but my experience gives you this sound advice :
Acieve a rough 100 yard zero, using a half way powder charge, with the bullet a bare minimum off of the lands, by firing a single shot at 25 yards, adjust your scope, and examine the case.
If the case doesn't show over pressure, increase the charge slightly, then do another single shot at 50 yards, then repeat all of this at 100 yards, but for a fiveshot group.
Assuming you still don't have pressure signs, and you feel there's room for improvement, keep the charge the same, but back off very slightly on the overall length.
Back off in very slight increments, perhaps by using the measurements that Berger bullets suggest on their site.
Once you've found the perfect OAL, THEN work on slightly increasing the powder charge.
All of this is whilst constantly checking for pressure signs.
Once the charge weight and OALare established, then consider trying different primers, if you can be bothered.

 

[jimirwin]

Did essentially my first ladder today and still learning on load development. I am following the process of the ladder testing article by Jim Baney pinned above on this board. He doesn't really cover seating as he knows the seating for his load already.

Here are the results from three ladders at 500 yds...same loads on each ladder. I did a pressure test last time and got pressure around 61.7 or so, so I backed up from there to 61.4 and worked down by .4 grains. I used .020 off for all.

Picture below has all the details, but summary is that shots 2-5 had vertical of .6", .6", and 1.5" in the three ladders. This covers 59.8 gr to 61.0 gr and covers avg velocity of 2919 to 2984. Somewhat surprised that the vertical was very similar for 65 fps difference in high and low avg, but the results are what they are.

Would you work between 2 and 3 (avg velocities of 2919 and 2931) or 4 and 5 (avg velocities of 2964 and 2984)? Those two had closer velocities to each other....or would you go smack in the middle of 2 and 5 (avg velocities of 2919 and 2984? Advantages of between 2 and 3 or 4 and 5 are closer velocities but advantage of going between 2 and 5 is a much wider node. I'm not concerned with getting max velocity and more focused on best accuracy.

And seating depth should be tested and whatever charges I move forward with. Should I do seating next on a single charge? Or refine the charges first and then do seating?

Many thanks.



Starting conditions - 67*, 73%, 29.95 and ended at 71*, 63% and 29.97.

Loads
1 - 59.4
2 - 59.8
3 - 60.2
4 - 60.6
5 - 61.0
6 - 61.4

View attachment 136487

Did essentially my first ladder today and still learning on load development. I am following the process of the ladder testing article by Jim Baney pinned above on this board. He doesn't really cover seating as he knows the seating for his load already.

Here are the results from three ladders at 500 yds...same loads on each ladder. I did a pressure test last time and got pressure around 61.7 or so, so I backed up from there to 61.4 and worked down by .4 grains. I used .020 off for all.

Picture below has all the details, but summary is that shots 2-5 had vertical of .6", .6", and 1.5" in the three ladders. This covers 59.8 gr to 61.0 gr and covers avg velocity of 2919 to 2984. Somewhat surprised that the vertical was very similar for 65 fps difference in high and low avg, but the results are what they are.

Would you work between 2 and 3 (avg velocities of 2919 and 2931) or 4 and 5 (avg velocities of 2964 and 2984)? Those two had closer velocities to each other....or would you go smack in the middle of 2 and 5 (avg velocities of 2919 and 2984? Advantages of between 2 and 3 or 4 and 5 are closer velocities but advantage of going between 2 and 5 is a much wider node. I'm not concerned with getting max velocity and more focused on best accuracy.

And seating depth should be tested and whatever charges I move forward with. Should I do seating next on a single charge? Or refine the charges first and then do seating?

Many thanks.



Starting conditions - 67*, 73%, 29.95 and ended at 71*, 63% and 29.97.

Loads
1 - 59.4
2 - 59.8
3 - 60.2
4 - 60.6
5 - 61.0
6 - 61.4

View attachment 136487

I'm learning a lot from this and like the concepts.
AND I have something to offer that I see no-one mentioning. That is headwinds/following wind effects. It has been absolutely amazing to me to see how much these affect vertical shot placement. If ladder testing is all about vertical, then this a variable to be controlled. Headwind seems to raise POI (point of impact), while tail wind lowers POI. Ignoring these can drive one batty at long range!

Just another (like we needed more, eh?!) variable to watch.

Jim Irwin
Central Texas