Unusual ladder test results

[Bayourambler]

My Dad and I are developing a long range load for his new Bergara B14 in 6.5 CM. I’ve come trust using my chrono and using the ladder test system, it seems to get me very close quickly. He prepped a few rounds with fed 210gm primers ,H4350 and 140 Eldm bullets. I set up cardboard at 300 yards to catch the hits and he shot .3 grain increments through the chrono. I recorded velocities and found a flat area in the 39 grain area. We loaded 4 rounds at 39.1 to shoot a group at 100 yds because the wind was about 10 mph. It shot great with good chrono numbers. .77 moa with a sd of 7.5 at 2700 fps. I can’t wait for a calm day to shoot this at 300 yards! The thing that I can’t understand is, how can there be so little verticle variation on such a wide range of velocities? It doesn’t make any sense. I’ve only done ladder tests maybe 10 times , but there always have been changes in impact at 300 yds. Any ideas how this happens?

 

[Bfh_auto]

Barrel harmonics and velocity effect point of aim.
That is about the same vertical that I get at 300 yards unless it's a sporter barrel.

 

[Steve in NC]

Bayourambler,
One thing I can say about shooting groups at extended range is that as the wind increases you verticle dispersion has a tendency to decrease. I use to shoot 600 and 1000yd benchrest for many years and have scored or refereed many targets over that time span. Many times on very windy days guys would get back their targets that were very wide but say 6" total of up/down on a day when the wind was howling. They would marvel at the group and say, "boy if there wasn't any wind today I could have shot a X.XXX" based on that smaller vertical. But on calm days those same guys were left scratching their heads. Have seen it over and over.
The first HG match I ever won I was shooting against 2 former national champions and the 4th guy wasn't there because their entire relay didn't get all of their shots on paper so the entire relay was DQd. That is how bad of a March day it was to be shooting. I won the shootoff with a 12.6" wide by 4-5" up/down group against a 16" and 18" groups and they had the same vertical measurements roughly. Very wide and little vertical.

I guess the long story short is try to pick less windy days to ladder test. Even though you are looking for vertical dispersion only in ladder test, that wind can skew your results. That would be my educated guess based on past experience.

Steve

 

[Bayourambler]

Barrel harmonics and velocity effect point of aim.
That is about the same vertical that I get at 300 yards unless it's a sporter barrel.

Maybe next ladder I’ll shoot 400-500 yds on a calm day?

 

[JFrank]

Wind flags are a huge part of load development. Good thing you had a chrono with ya

 

[jmorris]

Wind can change things quite a bit even as close as 300 yds.

A steady 10 mph in one direction is one thing but watch a field of tall grass and you can see all sorts of stuff going on, back and forth, side to side and even swirls.

Some barrels are right hand twist, some left hand twist but if you have a right hand twist barrel and the wind is from the left, your POI will be to the right and down. If it’s from the right it will be to the left and high.

If it’s from behind you, POI will be high (same as shooting up or down hill) and from the front, will be low.



Once guys have rifles that shoot “bug holes” in calm conditions, that opens up an entirely different level of things to learn.

Lots of folks buy stuff that they have read “shoots like a laser” but a beam of light is just different than a bullet in flight.

For lots of us, it’s splitting hairs but if you go to a benchrest match it looks like they are trying to scare birds away with all the wind flags everywhere.



That’s because lots of people there have rifles than can win, the difference between the winners and losers are when they pull the trigger.

 

[TheDomFather]

View attachment 836292 View attachment 836293 View attachment 836294 My Dad and I are developing a long range load for his new Bergara B14 in 6.5 CM. I’ve come trust using my chrono and using the ladder test system, it seems to get me very close quickly. He prepped a few rounds with fed 210gm primers ,H4350 and 140 Eldm bullets. I set up cardboard at 300 yards to catch the hits and he shot .3 grain increments through the chrono. I recorded velocities and found a flat area in the 39 grain area. We loaded 4 rounds at 39.1 to shoot a group at 100 yds because the wind was about 10 mph. It shot great with good chrono numbers. .77 moa with a sd of 7.5 at 2700 fps. I can’t wait for a calm day to shoot this at 300 yards! The thing that I can’t understand is, how can there be so little verticle variation on such a wide range of velocities? It doesn’t make any sense. I’ve only done ladder tests maybe 10 times , but there always have been changes in impact at 300 yds. Any ideas how this happens?

See my ladder testing using H4350 and 140gr ELD-M

 

[Varminterror]

It’s only 300yards, you can’t expect much vertical. OCW is typically shot at 300, ladders are better done at 600.

 

[JFrank]

See my ladder testing using H4350 and 140gr ELD-M

You’ve a good bit of testing here, I always appreciate someone taking their time and resources then posting.
When conducting these horizontal test one thing I look for is location of neighboring groups, this tells me that even though the FPS may vary slightly the Bullets will impact the target in the same area. Don’t recall what distance this however
I do believe with that in mind I would load the ELD at 41.8

 

[Varminterror]

See my ladder testing using H4350 and 140gr ELD-M

That wasn’t a ladder test.

 

[TheDomFather]

That wasn’t a ladder test.

Why not?

 

[Varminterror]

@TheDomFather - because you didn’t do anything within the parameters of a ladder test. Read up on the common parameters of Creighton Audette’s Ladder test, which started going around in reloading magazines over 20 years ago.

Ladder Test development discussion at 6mmBR.com

Your video, once you get past the seating depth test, is not a Ladder Test, it’s a Velocity Curve. Velocity curves can be fired without a target, and really don’t need that many shots to be fired.

The biggest give away that what you did is NOT a “ladder test” - you’re shooting at different targets.

Also, you’re shooting at 100yrds. There’s not nearly enough vertical dispersion to tell us anything about the charge envelope at 100. 300yrds should be the absolute minimum, and 600 is typically considered the standard.

In general, a Ladder test should be:

1) All shots on one target/POA

2) 600+ yards, no less than 300, and if you can’t access 300 at least, other methods are more appropriate.

3) Incremental charge weight shots taken round robin.

Velocity Curves are great, but it’s not a Ladder Test.

 

[JFrank]

Jason’s testing is very well done and it works extremely well.

 

[Bayourambler]

Looking into this information I can take away that I need to be more patient to wait for a calm day, and extend the range of testing. I have always had trouble in headwinds, I'd rather shoot in a 15 mph steady cross wind than a 5 mph varying headwind any day!

 

[Varminterror]

Jason’s testing is very well done and it works extremely well.

If Jason is Dom, he’s put a LOT of rounds down his barrels - as in likely half of his barrel life in his 6.5’s, based on his videos - and doesn’t seem to really have a happy place for his loads. I appreciate he’s new to all of this, but there are proven methods reloaders have been handing around for generations to develop loads in far less round than he’s had to take.

 

[JFrank]

If Jason is Dom, he’s put a LOT of rounds down his barrels - as in likely half of his barrel life in his 6.5’s, based on his videos - and doesn’t seem to really have a happy place for his loads. I appreciate he’s new to all of this, but there are proven methods reloaders have been handing around for generations to develop loads in far less round than he’s had to take.

I was referring to Jason Baney the tester in the article (you ) posted.
The colored bullet ladder test shot in round robin at the competition distance is a favorite with many around the country however it is not the only way to skin a cat, many shooters do not have access to the longer ranges or struggle testing at those distances due to conditions, I’m one myself therefore I’ll perform ladder test at shorter distance 2-300 yards and seating as well then confirm at 550 or 600 yards
I rarely need more than a few rounds for a ladder maybe twenty for seating, testing and confirming a load is on going throughout the life of a competition Barrel, they are a disposable item.
My ladders are in a single POA format .2 grain increments

 

[Varminterror]

I was referring to Jason Baney the tester in the article (you ) posted.
The colored bullet ladder test shot in round robin at the competition distance is a favorite with many around the country however it is not the only way to skin a cat, many shooters do not have access to the longer ranges or struggle testing at those distances due to conditions, I’m one myself therefore I’ll perform ladder test at shorter distance 2-300 yards and seating as well then confirm at 550 or 600 yards
I rarely need more than a few rounds for a ladder maybe twenty for seating, testing and confirming a load is on going throughout the life of a competition Barrel, they are a disposable item.
My ladders are in a single POA format .2 grain increments

Ah - I’ve read that article many times over the years, never paid attention to the author’s first name.

But yes, this... all of this...

I get stuck (cough, lazy, cough) sometimes and will run a 300yrd Ladder for my first run, maybe or maybe not do a more focused confirmation/refinement ladder at 600. Compare all of it to the velocity data. Only tweak seating depth if the groups ask for it, or application demands it (cheat by referencing other shooters’ jump lengths). The challenge for me is being patient through break in - I could be done with load development within 30rounds most of the time, settling in on a 1/2-3/4moa load with single digit SD’s, but the barrel is still a long way’s from settled in...

 

[JFrank]

Agreed “
I will test components and seating depth, then move toward load development creating a diagnostic tree as I go along; (knock on wood) I’m able to spot tendencies and correct them as my throat erodes or temperature changes enough to warrant adjustment.
Mostly I’ll start from a solid jamb finding my CBTO for a bullet such as Berger 108 will be totally different than Sierra 107 , I do this for my initial ladder test giving me one direction to adjust. Typically I work with Tangent ogive projectiles findings a bit of jump is the final setting.
I also have noticed that testing charges on a warm day or having your Ammo box in the sun can give you a slightly lower node, I believe that is what you’ll see pictured below, where all looks great at 29.6 on a warm day but a month later you’ll need to adjust (add HP) to get the group your seeking, in my case I require under an inch at 550 to be competitive. My current load is 30.0 Varget at .018 jump this summer I’ll have to drop a tad closer to the 29.7
But only a quick ladder test will tell me that.

I don’t rely on a chrono cause I don’t know ES from BS I just read the target.

Hopefully I can contribute to the forum

Jim

 

[JFrank]

Now that I’ve had my morning coffee,
I’ll add that a lot of shooters will start with a fresh barrel and a new box of 100 brass fire form those brass at a modest charge with a cheap bullet prior to any load development.
Jim

 

[Varminterror]

Now that I’ve had my morning coffee,
I’ll add that a lot of shooters will start with a fresh barrel and a new box of 100 brass fire form those brass at a modest charge with a cheap bullet prior to any load development.
Jim

I just hate doing that with barrel burners. I buy barrels two at a time for that reason, but I’d still rather do my fireforming during a smaller match to feel better about the rounds being sent down the barrel.

 

[JFrank]

I just hate doing that with barrel burners. I buy barrels two at a time for that reason, but I’d still rather do my fireforming during a smaller match to feel better about the rounds being sent down the barrel.

Some fellas screw on an older barrel just for FF, lots of ways to skin a cat

 

[JFrank]

Let me ask you this,
If you FF new brass at a match are you hitting them with a full charge?

 

[Walkalong]

I always fire formed Benchrest cases in 6PPC with full power loads. Fills the case out better. Did this in a local "fun" match when I could.

 

[Varminterror]

Depends on how I want to fireform. For Dasher, I run a false shoulder, and blow them out with full house loads, assuming it fits in the case. If I jam into the lands for fireforming, no, i don’t use max loads.

 

[Walkalong]

Well, I was always into the lands.