I've read up on this and have reloaded for a bit. But I am asking if someone can give me a step by step on the best way to do this? Do I start with powders and then go to seating depth and when do I try different bullets? Sorry to sound like a dummy ..but I guess I might be in regards to this! It gets confusing when I read articles on this because they always skip what order things are done in. Thanks for any help!
Ladder testing
- Thread starter Bobhunts
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Aeolus
Well-Known Member
Pick the brass, primer, powder, and bullet you want to shoot. To do a full test start at the lightest powder charge and go past the max maybe a grain or do. I try and start 15 tho off lands. Load them 3 tenth of a grain and up. Example my 338 Norma I started with 87 went 87.3, 87.6 87.9, 88.2 so on. Shoot all of them in 5 shot groups over a chrono and write it down. You will see the sd and es go high to low to high 3 times. Shoot off the middle lowest es and sd. You can tune from there. Example 88.5 did good with my 338 so I did 88.3-4-5-6-7-8-9 and 88.8 shot an es of 15 so I stuck with it. Then work on seat depth, start jammed, 3 off, 5,10,15,20,30,40 one of those will give you a 1 hole 5 shot group. From there that's your load and seat depth. Check it every 400 rounds or so.
Aeolus
Well-Known Member
Now the way to cheat the full load development is choose your caliber and bullet. Look online between long range hunting, snipers hide, 24 hour, accurate shooter, several people will be close. Example I knew somewhere between 88.5 and 89.2 I would have a node sonyou could start at 88.2 and go to 89.2 and find it then do the same thing on seating. But on a new rifle I do the full test. That forms my brass well and breaks in my barrel so it will speed up and I will catch that extra speed. It also runs you will with the rifle.
Oh ya for a target do the test at 100 yards or meters how ever you shoot. I get white cardboard box and make 6x6 squares and add black pasters and put them on the lines this way I can stay and shoot and take that whole target home and look at it.
Also the waterline will be the same on those 3 lowest numbers. They will have hit in the same spot.
Oh ya for a target do the test at 100 yards or meters how ever you shoot. I get white cardboard box and make 6x6 squares and add black pasters and put them on the lines this way I can stay and shoot and take that whole target home and look at it.
Also the waterline will be the same on those 3 lowest numbers. They will have hit in the same spot.
Highdesertmike
Active Member
The reason for a ladder test is to find the harmonic node in your barrel where the bullet is leaving the muzzle at the same time that the harmonic vibration is closest to the chamber. Just as a guitar string vibrates as you pluck it, your barrel vibrates back and forth, causing the muzzle to move in an "epicylic" pattern.
As stated above, load your rounds with an increasing charge weight. I would fire them one at each load, carefully watching for pressure signs. Fire each powder charge at it's own target, keeping the same point of aim. Shoot one of each: IE 45g, 45.5, 46, 46.5 (whatever your steps are) then go back down: 46.5, 46, 45.5 45.
Now, look at your target, you should see a "node" where the vertical spacing of the shots the least, usually you will see this in a 1G to 1 1/2G spread. Do NOT focus on the groups, focus on the vertical dispersion. Take this range of charge weight that gives you the least vertical dispersion and concentrate on the charge weight in the middle. You can tweek it from there.You now have your powder charge identified. Now focus on seating depth and overall group size, loading three to five round groups and adjusting your seating depth to find a tight group. Remember to only change one factor at a time.
Perform this at 300yards if possible, 200 is OK. At 100Y you typically wont see enough change to make much sense.
As stated above, load your rounds with an increasing charge weight. I would fire them one at each load, carefully watching for pressure signs. Fire each powder charge at it's own target, keeping the same point of aim. Shoot one of each: IE 45g, 45.5, 46, 46.5 (whatever your steps are) then go back down: 46.5, 46, 45.5 45.
Now, look at your target, you should see a "node" where the vertical spacing of the shots the least, usually you will see this in a 1G to 1 1/2G spread. Do NOT focus on the groups, focus on the vertical dispersion. Take this range of charge weight that gives you the least vertical dispersion and concentrate on the charge weight in the middle. You can tweek it from there.You now have your powder charge identified. Now focus on seating depth and overall group size, loading three to five round groups and adjusting your seating depth to find a tight group. Remember to only change one factor at a time.
Perform this at 300yards if possible, 200 is OK. At 100Y you typically wont see enough change to make much sense.
Thank you very much! This has cleared up so much.
odoylerules
Well-Known Member
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- Dec 6, 2016
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Alex's method is time proven and reliable!! Here you go...
https://www.longrangehunting.com/threads/tuning-for-long-range.192998/
https://www.longrangehunting.com/threads/tuning-for-long-range.192998/
It's interesting to me regarding ladder testing that Realtalk seems to focus on consistency in velocity, Highdesertmike seems to focus on consistency in point-of-impact on the target, and Alex Wheeler (pointed to by odoylerules) insists that you must focus on the confluence of both consistency in velocity and point-of-impact (because sometimes they won't coincide).
I can understand how consistency in velocity and point-of-impact would coincide. They seem like two sides of the same coin. I'm having a hard time wrapping my head around why they would not coincide. If I witnessed a flattening of velocity without a corresponding flattening of point-of-impact, I'd probably figure that I'd messed up the shot and the chronograph is correct (or more likely, I'd blame it on the wind).
Can someone help me understand why these two effects aren't the same thing?
I can understand how consistency in velocity and point-of-impact would coincide. They seem like two sides of the same coin. I'm having a hard time wrapping my head around why they would not coincide. If I witnessed a flattening of velocity without a corresponding flattening of point-of-impact, I'd probably figure that I'd messed up the shot and the chronograph is correct (or more likely, I'd blame it on the wind).
Can someone help me understand why these two effects aren't the same thing?
Highdesertmike
Active Member
Jebel:
I believe that if your loading techniques don't produce consistent velocities, your never going to get any kind of respectable group. So paying attention to the details should get you loads with low ES / SD 's.
However, you can have a load with a very low ES / SD, and it won't shoot or group. This is where first tuning the velocity to find the node of the barrel comes into play. If you can picture the muzzle of your barrel vibrating in an epicyclic pattern (a circle that rolls around the inside or outside of another circle) , if not timed correctly, the bullet may leave the muzzle on one shot when the barrel is at 11 o'clock, the next shot, it is at 3 o'clock, the next it is at 8 o'clock. This will result in a wide grouping down range. But if the velocity is timed so that the bullet exits when that vibration is at it's minimum, the group will be tighter.
Finding this in your barrel is what is referred to as a "Node" Each barrel may have two or three, each presenting themselves at different velocities.
Hope this answers your question.
I believe that if your loading techniques don't produce consistent velocities, your never going to get any kind of respectable group. So paying attention to the details should get you loads with low ES / SD 's.
However, you can have a load with a very low ES / SD, and it won't shoot or group. This is where first tuning the velocity to find the node of the barrel comes into play. If you can picture the muzzle of your barrel vibrating in an epicyclic pattern (a circle that rolls around the inside or outside of another circle) , if not timed correctly, the bullet may leave the muzzle on one shot when the barrel is at 11 o'clock, the next shot, it is at 3 o'clock, the next it is at 8 o'clock. This will result in a wide grouping down range. But if the velocity is timed so that the bullet exits when that vibration is at it's minimum, the group will be tighter.
Finding this in your barrel is what is referred to as a "Node" Each barrel may have two or three, each presenting themselves at different velocities.
Hope this answers your question.
If you can shoot to 800+ yards, you don't need a chronograph. Forget the wind. Vertical dispersion is all your looking at so long as your gun is accurate and your holding it still, the target will tell all. Other criteria has merit but they're not ladder tests.
Highdesertmike and Mike 338, your comments are well taken. I do understand the idea of a harmonic node in the barrel. But what Alex Wheeler was saying (first link above by odoylerules) was that he's looking for both when impacts cluster (vertically) and velocity variance is simultaneously low. Keep in mind, we're not talking about low velocity variance across multiple loads of the same charge, it's low variance over cases with different charges (just as low variance in POI across cases with different charges). This is what inspired my question. Isn't lower variance in velocity across different charges apt to produce lower POI variance as well? And isn't it related to the same notion of harmonic node?
FYI, Jason Baney (the second link by Mike 338) seems to disagree with me. He hardly mentions velocity in his description, and when he does, he suggests that changes in its patterns are independent of changes in POI (though he doesn't quite say so explicitly).
FYI, Jason Baney (the second link by Mike 338) seems to disagree with me. He hardly mentions velocity in his description, and when he does, he suggests that changes in its patterns are independent of changes in POI (though he doesn't quite say so explicitly).
Highdesertmike
Active Member
OK, got it. Yes. As you perform this testing and find the node, everything tightens up. The node usually presents itself in a 1 to 2 grain window. So in essence, the barrel "likes" a charge weight between a certain range. IE: you find that a charge starting at 43.5 grains and 44.8 grains gives you both low ES/SD AND little vertical change, then that is your window. So if we settle on the middle 44.1 /44.2 grains as our load, we could be 1/2 grain on either side of that and still have the accuracy we desire.
It only stands to reason that everything being equal, the faster bullet is going to have less time to be affected by gravity prior to target impact, and should hit higher than the slower one.
I'm not a Mathematician nor a Ballistician. This is probably beginning to get over my head. This is how I understand it and I know it works for me. I'm not qualified to argue another person's method as wrong or right. The books produced by Brian Litz (Berger Bullets Ballistician) get into all this in depth and may be a good resource for further explanation.
Great conversation all involved. Thanks
It only stands to reason that everything being equal, the faster bullet is going to have less time to be affected by gravity prior to target impact, and should hit higher than the slower one.
I'm not a Mathematician nor a Ballistician. This is probably beginning to get over my head. This is how I understand it and I know it works for me. I'm not qualified to argue another person's method as wrong or right. The books produced by Brian Litz (Berger Bullets Ballistician) get into all this in depth and may be a good resource for further explanation.
Great conversation all involved. Thanks
Agreed.
I would point you to Alex's and Jason's methods as others have. It is correct that it is best to find the point of impact and velocity nodes that coincide. The point of the ladder test alone is to find a small vertical point of impact change. Sometimes this can happen due to positive compensation. When that is the case the load will be very well tuned for that distance and should be very stable in different conditions but may not necessarily be great at shorter distances(should still be acceptable) and may not have tiny ES in velocity. In my testing I have found the later to be rare but have seen it. I feel a ladder performed at 600 plus yards is the absolute best and quickest way to a load that will be great in many different conditions.
