Thread: 440m ladder test

Originally Posted by marky123

As far as I understand,a ladder test is the relationship between POI and velocity.If unsuitable powder charges are used then they are nowhere near their next or previous.If it is,then they are closer together,hence 3,4 and 5 are suitable charge weights in this instance.Further testing with those charge weights will prove or disprove that.Happy to be proved wrong.

https://www.6mmbr.com/laddertest.htm...%20of%20primer.

SUMMARY: Repetitive, round-robin Ladder Testing with multiple charge weights can reliably identify those loads which deliver minimal vertical dispersion at long range. ... While the Ladder Test method is primarily used to divine optimal charge weight, it can also be used to find the best seating depth or brand of primer.

Originally Posted by marky123

As far as I understand,a ladder test is the relationship between POI and velocity.If unsuitable powder charges are used then they are nowhere near their next or previous.If it is,then they are closer together,hence 3,4 and 5 are suitable charge weights in this instance.Further testing with those charge weights will prove or disprove that.Happy to be proved wrong.

Yup, but you are shooting single loads. How can you be sure the vertical dispersion is due to the load and not due to your shooting.

That is why I keep stressing 5 shot groups. If you can show me 5 shots of the same load, all on the same vertical plane, then I will be convinced.

The correlation between increasing load and increasing velocity is not completely linear.

The target you posted has vertical all over the place (some of the slower loads land higher etc), so it does not really show much. If you were shooting a whippy hunting barrel, that may have been due to harmonics causing the projectile to leave the muzzle at different points in the whip, but then you would struggle to shoot accurate groups at most time.

All things working well, you would expect to see poi climb as the charge weight increases. Where that climb becomes contracted for equal increases in charge, is likely to be a node. I am not seeing any of that on your target (based on poi)... I do however see a potential node if you look at the speeds.

2 questions:

1) what chrony are you using ?
2) rifle ? particularly barrel profile ? is it a noodle or something a bit more beefy like HMR ?

Originally Posted by ebf

Yup, but you are shooting single loads. How can you be sure the vertical dispersion is due to the load and not due to your shooting.

That is why I keep stressing 5 shot groups. If you can show me 5 shots of the same load, all on the same vertical plane, then I will be convinced.

The correlation between increasing load and increasing velocity is not completely linear.

The target you posted has vertical all over the place (some of the slower loads land higher etc), so it does not really show much.

Assuming the chrony and the shooter (not me) were working correctly and the conditions were good (there was no readable wind) then the test shows less POI dispersion and velocity between some shots to others.
You can reasonably presume that those charge weights are ‘good’ loads.We will then repeat the ladder test hopefully under the same conditions with a smaller variance of charge weights at the same distance.Hopefully some of those loads will be ‘good’.Then we will select a load and shoot groups with it to confirm.

If that works then we have found a ‘better’ load with 20 shots.

More charge weight is not linear with velocity,I haven’t said it is.
We will shoot some 3 or 5 shot groups but only when we have dialled in a ‘good’ load.

So it shoots 1 MOA with a slight change in powder loads is all I can interpret from that. If saving powder and projectiles is the aim of the test
( and getting the job done in a short time frame ) Then it looks good. These new idea methods seem a bit odd to me, I cant see how one shot groups prove anything at all.
As you say the rifle is a hunter and it may never get better than this either. Although its pedigree should help with smaller groups.
IIRC most CM's shoot 2209 well with 41.5 Grains for 143's sorry 140's

I went through a whole bunch of OCW and other tests with mine only to find this out a short time later.

Originally Posted by johnd

So it shoots 1 MOA with a slight change in powder loads is all I can interpret from that. If saving powder and projectiles is the aim of the test
( and getting the job done in a short time frame ) Then it looks good. These new idea methods seem a bit odd to me, I cant see how one shot groups prove anything at all.
As you say the rifle is a hunter and it may never get better than this either. Although its pedigree should help with smaller groups.
IIRC most CM's shoot 2209 well with 41.5 Grains for 143's sorry 140's

I went through a whole bunch of OCW and other tests with mine only to find this out a short time later.

I shoot mine with 140s and use 41.5 of 2209,but I don't even get 2600fps.
The first time we went out matey shot a 2" three shot group with Hornady Match ammo.

Originally Posted by marky123

I shoot mine with 140s and use 41.5 of 2209,but I don't even get 2600fps.
The first time we went out matey shot a 2" three shot group with Hornady Match ammo.

Interesting Marky, do you have a short..ish barrel. My Speed was 2700 for a 26 inch barrel. Verified with drops and data out to 600 yds for 1/2 MOA on a good day, but usually "blew" out to 1 1/2 with wind. Still maintained 1/2 MOA vertically
Dont take any of the critique, we have given, the wrong way we just obviously do things differently.

Group size is irrelevant for a ladder test, especially at that distance. There is no consistent speed increase or a flat spot to call a node. A ladder test is an advanced technic for good reloaders who uses the right procedures through brass prep to bullet seating. So if you are using mix brass not trimmed as the same batch. Loaded with pulled bullets. Then you are wasting time.

Fuckit , you can lead a horse to water...

Good luck to you.

My observation has been that most people who come on here asking about ladder tests already know the method they are intent on using, and will go on to interpret the data in the way to which they are predisposed, irrespective of the advice received. The recipe they end up with may or may not be better than any other, but they will be more comfortable with it than they would otherwise be, having received from the test results what they perceive to be validation of their choice.
Happy shooter. Not my rifle.
Hard to argue with that.

I might add that there are already a lot of opinions on ladder testing and load development in general on this site for anyone who cares to look these out.

Start shooting groups with (40.8) 41-41.6gr and see what groups best with the lowest ES at the same time. After that, play with jump to fine tune.

If I have read and measured your target correctly the group of shots all fall within 36 cm or 14 inches in old money vertically and with one exception 15 cm horizontal 6 inches, There is no indication of point of aim and I understand that for your purpose that's not important.
However you seem to have produced a group of just over 2 moa at a range that most people would be over the moon about, so I can't see how it proves anything. Chances are choosing one of your ladder loads and firing that number of rounds would produce a similar looking target.

Marty, there is no group !

They have produced a target where there are 10 individual shots, each at a different charge weight. Instead of seeing vertical climb for increasing loads, the poi is all over the place.

Several people have pointed this out, and also tried to steer the op in the direction of velocities as a higher quality metric, but he seems to insist on loads 3,4 and 5 being where it is at...

In the article link posted earlier, the author mentions "rung groups" for the ladder. So shooting 3 at each charge weight. That would show that the shooter is actually able to shoot accurately to a poa, especially if done in rotation as described...

https://r.tapatalk.com/shareLink/top...ink_source=app

Here's the video and corresponding thread I talked about earlier

Sent from my SM-N975F using Tapatalk

Originally Posted by The Claw

https://r.tapatalk.com/shareLink/top...ink_source=app

Here's the video and corresponding thread I talked about earlier

Interesting video @The Claw, tx for posting. He makes several really valuable points about choosing the middle of the node for extra security. Something I've seen time and again at Seddon. Typically at least one of the days during nationals week, it turns southerly and temps drop. Guys who are at the margins of nodes (the speed demons) suddenly find themselves with massive vertical issues.

The other comments I found interesting were his statements about horizontal dispersion at long range due to seating depth. Probably more of an issue with the VLD type projectiles.

It would be a cool exercise to run a blind comparison between a long range ladder and a short range chrony only type node hunt, and see if the results differ. I suspect they will be very similar.

My over-riding comment is that in order for ladder tests to be of value, the shooter better be shit-hot and able to shoot to very small margins of error

And further interesting information

https://r.tapatalk.com/shareLink/top...ink_source=app

Sent from my SM-N975F using Tapatalk