Ladder testing at 1k- Detailed article and video

BergerBoy

Well-Known Member
Joined
Nov 22, 2014
Messages
282
Location
I'm NOT a patriot... I am a U.S. Constitutionalist
Mikecr,
I invite you to Northern Nevada to do some shooting sometime. I am a life long student of long distance shooting and love to learn all I can from whom I can. Shower me with all your knowledge...
Seating depth can/is huge in grouping with out a doubt, but at longer distance (over 1k yds) I have found higher ES issues to be the main reason for vertical dispersion.
On burn efficiency, I just noticed a correlation between smaller groups and very low ES. I shot just over a .25 in yesterday with a load that had an ES of 8 fps. My other loads had ES of ~ 28 fps and I grouped .75-1.25 in. I'm not saying you always have to have an ES that low to shoot that small of groups but from my experience it helps and in the longer shoots-over 1500 yds, it helps a lot.
It was just something that caught my attention.
 

Alan Griffith

Well-Known Member
Joined
Aug 22, 2005
Messages
636
Location
Mouth of Hobble Crk Canyon, Utah
I'm going on the record to say i've modified my procedure slightly. I now run an initial OAL seating depth test before running the ladder.

I load up 4 batches of 3-shot groups seated .005", .045", .085" and .120" off the lands. I shoot those to determine if the barrel/bullet/powder combination prefers something, right up front.

I just completed my testing of Rel 17 and both the 129 and 142 gr LRAB in my light 6.5x47 and those are such long bullets, I had to run an initial OAL length test using .005", .020", .040" and .060" off the lands.

I ended up with the 129 gr giving me .55 moa, 2977 fps and 10 SD for a 5-shot group. The 142 gr LRAB went .65 moa, 2803 fps and 10 SD. These were both on cases that were on their 23rd firing. Maybe if I used new/newer brass the SD would reduce. 24.5" #3 Bartlein barrel.

Alan

On going on record to explain how I've changed the excellent Audette ladder load development system.

Using the different colored markers is an excellent idea. The problem i've run into with this is that depending up the distance, caliber size and quality/power of spotting/rifle scope, the shooter may not be able to see the impacts down range "while" shooing the ladder. When shooting a ladder it is necessary to see/know which shot/impact is which. In addition, if you call a bad shot, you need to know which impact is the bad shot.

A friend of mine from Albuquerque taught me a new technique; home made DirtyBird or Shoot N See targets. Targets that leave a large black impact on a light/white colored backing. I take an 8'x4' sheet of plywood or similar sheet of stiff backing material and cut it in two so I have two 4' x 4' sheets. I then buy a roll of black plastic. Mine was about 20' x 8'. I cut that down to 4' x 4' sheets which are stapled to the plywood. I then take a $.97 cent can of white spray can and spray the entire sheet of black plastic, white. Let it dry and add bright orange aim points. Select your desired distance to shoot at and let fly. With my Zeiss 15-45x spotter I can easily see 22 cal hits at 660 yds. When the bullet hits, the white paint, directly around the impact hole, chips off, exposing the black plastic, easily seen at extended distances.



Above you can easily see my LV Steel 1/2 silhouette, used as a sighter target then looking at the right 4'x4' DirtyBird target you can see my ladder; 3 shots upward, 3 shots across (accuracy node) and 2 more shot above that.

That's my target. How I bring loads to the range is new as well. We all know that BR shooters load their ammo at the range. I modify that by bring prepped and charged cases to the range and seat bullets "as necessary". Below is an MTM ammo boxes with 100 prepped and charged cases.



The first row across is my starting row; for example all are 40 gr. The 2nd row has a .2 gr increase (6.5x47Lapua) and so on and so on until the 10th row has 41.8 gr. I take small, light, handheld press to the range with me with the seating die already pre-adjusted to my desired setting depth. At the range, I fire one round at my steel target to confirm a hit and so I can adjust closer to my intended point of impact. In this case the center orange dot on the 4'x4" DirtyBird target. I then start up the ladder, seating one bullet and shooting; marking the POI on a separate sheet of paper. Even with my NF scope set at 22x I can see the hits. Once the ladder has been shot the MTM ammo box should look something like this.



This ladder showed that 40.4, 40.6 and 40.8 gr showed promise. Now, I take the next 3 unloaded, charged, cases from the 40.4, 40.6 and 40.8 gr rows and seat bullets. I shoot each 3 cartridges at individual aiming spots for 3, 3-shot groups to see which group better. I'm especially looking for zero to nil vertical spread. Once I've done that the MTM box should look like this.



At this point I'm hoping to have narrowed it down to 1 or 2 different powder charges; say 40.6 and 40.8 gr. I then want to play a bit with seating depth; loading up 3 more of the same powder charge. Once I've shot those, my MTM box looks like this.



Now I may want to play a bit more with seating depth; going in or out a bit more….or……in the opposite direction. My box now looks like this.



At this point, it's time to pack up and go home where I don't need to pull any bullets. I might want to play a bit more with seating depth or try different primers but the majority of my Audette Ladder testing is done and all in one trip and I've only shot a max of 31 rounds; saves on components and barrel life.

Questions?

Alan
 

dsculley

Well-Known Member
Joined
Feb 13, 2014
Messages
310
Location
Orange Beach, AL
After reading the article I really don't see any advantage of this method compared to a correctly developed and executed cow test. Both tests are designed to find a node where point of impact across multiple charge weights are similar. Many people use the ocw method initially then use a ladder test to confirm. They usually find the ocw node is the same as the ladder node.
 

Bart B

Well-Known Member
Joined
Dec 25, 2005
Messages
2,758
One thing I've learned shooting long range matches shooting thousands of 3-shot groups in strings of 17 to near 30 shots......

Their sizes have a 4X to 5X spread.

Sometimes, three shots will cluster inside 3 to 4 inches. Other times they are 15 inches or more extreme spread. Once in a while they're a lot bigger.

Nobody I know of shoots 3-shot groups at any range with the same load that are always under a 10% spread in center to center of the widest shots.

Judging a load's accuracy with only 3 shots is a waste of my time.

If you've ever looked at the dozens of 5- and 10-shot groups shot with the same benchrest rifle and ammo over a 2 or 3 day match (long, mediuim or short range), you'll see a 3X to 5X spread in their sizes; sometimes more. 3-shot groups have bigger spreads than 5- or 10-shot ones. In spite of this, many, many rifle shooters testing their loads for accuracy think all 3-shot groups with the same load will shoot the same size groups and have no reason to shoot more shots in a group.

'Tis my opinion your loads putting those 3-shot groups on target are statistically equal. Shoot at least 20 shots with each load then compare those group sizes.
 
Last edited:

Bart B

Well-Known Member
Joined
Dec 25, 2005
Messages
2,758
Bart,
What is your load development process?
Ask folks about tools and their setup and use techniques producing best accuracy based on hundreds of 10-, 15- and 20-shot groups for a bullet, then use their ways and means. Way too much spread in group sizes across several 3- or 5-shot test groups for me. Never changed loads for different lots of powder, primer or bullet; barrels either, for that matter. Such ammo shot as accurate as the best of others.

I've never developed a load for any existing bullet used in competition; used what was typical for winning and setting records. Twice, I did develop a load for new bullets with new cases, but the component set and amounts were pretty closely guessed based on similar loads that have done very well.

All tests to verify were done with 15- to 25- shot groups shot from what's now F-class match positions. I think it's a waste of time, components and barrel life to hold onto a benched rifle resting atop stuff on the bench top held firm into my shoulder; way too many human variables that increase test group sizes and muzzle velocity spread for best accuracy.
 

Clark

Well-Known Member
Joined
Oct 19, 2006
Messages
744
Bart, I consider your 1997 20 shot group of 3.325" at 800 yards with a 308 to be beyond what I will achieve in my lifetime. My best rifle, 6.5-06, in my best year had me rated out to 600 yards for shooting at deer, and I am 65.

To me you are great sourse of info in that if YOU don't bother with some accuracy ritual, I don't bother. At least I can eliminate a few things.

But if you had a #1 taper instead of a Palma tapered barrel, would you be tuning powder charges then?
 

Bart B

Well-Known Member
Joined
Dec 25, 2005
Messages
2,758
No, I would not tune anything on the load for different barrel profiles. Maybe for different chamber throats, but not much. Never saw much difference in how far the bullets have to jump to the lands. As long as the rounds are straight and minimal bullet runout, all's well in accuracy.

There is no industry standard for the various barrel profiles. Some Palma rifle barrels are as long, thick and stiff as benchrest barrels. Having shot the same load of 168's in .308 cases through 30" long skinny barrels as well as thick ones and seen no difference in accuracy, I'm convinced the bullets are leaving at the right place in the barrel's vertical whip upswing to compensate good for velocity spread.

One interesting thing to me in that link in post 1 on Long Range Load Development..... That benchrest rifle's fired in free recoil; untouched by humans except for a finger on its few-ounce trigger. It's barrel will whip differently while the bullets go through it compared to how it whips when held against ones shoulder as it rests on bags atop a bench. Bullets from free recoiling rifles will have a low average muzzle velocity and a low spread in muzzle velocity compared to hand held ones against the shooters shoulder resting on bags. I've seen as much as 50 fps across 3 people shooting the same .308 rifle and ammo so tested; others have seen almost 100 fps.
 

Alex Wheeler

Well-Known Member
Joined
Jul 5, 2017
Messages
967
Location
Montana
Read, understand and follow the 1k ladder procedure if you can. Its by far the best way to do long range load development. ES is far less important than most think. If your under 20 fps, es has no effect on grouping. Most all successful 1k Benchrest competitors will tune at 1k, because it works.
 

John Porter

Member
Joined
May 25, 2019
Messages
21
Location
Australia
A VERY important couple of lines from the 1K ladder article.
"with hunting and tactical rifles, I try to test from a cold barrel because that is how the rifle will be used. Basically, you want to simulate the conditions in which the load and rifle will be used."
For all my hunting rifles I shoot five shot groups, allowing the barrel to cool off fully after each group. This is time consuming but I do load development for a few other shooters and usually have two rifles to work on, so I shoot one while the other is cooling down. Also adapted an air mattress 12 volt pump with a hose that fits into the chamber and cools the barrel in less than half the time.
 

Bart B

Well-Known Member
Joined
Dec 25, 2005
Messages
2,758
A VERY important couple of lines from the 1K ladder article.
"with hunting and tactical rifles, I try to test from a cold barrel because that is how the rifle will be used. Basically, you want to simulate the conditions in which the load and rifle will be used."
For all my hunting rifles I shoot five shot groups, allowing the barrel to cool off fully after each group. This is time consuming but I do load development for a few other shooters and usually have two rifles to work on, so I shoot one while the other is cooling down. Also adapted an air mattress 12 volt pump with a hose that fits into the chamber and cools the barrel in less than half the time.
If a stress relieved barrel is fit to a squared up receiver face, you can shoot 30+ shots 25 seconds apart and shots won't start stringing away from point of aim as the barrel heats up.

A friend put 40 shots into 1.92" at 600 yards fired at that rate with a Win 70 based 308 Win and Lapua 185 FMJRB match bullets. I have put 30 inside 6 inches at 1000 yards the same way with a Win 70 based 30-338 Win Mag; 15 Sierra 190s and 15 Sierra 200s, alternated. All started with cold barrels.
 
Last edited:

Trending threads

Recent Posts

Top