Would someone please explain the ladder technique of load developement.. thanks, Doc Stone :

There are a couple of people that will probably chime in with more knowledge than mine, but here is the basic idea.



As the bullet exits the muzzle, it will be deflected by the sideways-up and down vibration of the barrel. If all bullets had exactly equal transit times down the barrel, it would not matter where in the arc they exit. Since this isn't usually true, but it is usually true that bullets that exit at or near the end of the arc will be more consistent in their grouping.



Variation is a slippery devil to pin down, and group size is variation. It takes a lot of groups to determine how accurate a rifle is. So checking your group sizes is a slow, difficult way to improve accuracy.



A better approach is to set up something like half a dozen targets, and shoot at them with six different loads, perhaps half a grain apart in load. Shoot the various loads in random order, but shoot all the lowest loads at the first target, next lowest loads at the second target, etc. (ooops... before you start, a couple of fouling shots to warm the barrel... shoot slowly, attempting to keep the barrel at a constant temperature).



Finally, locate the center of all the groups you have shot. The 2-3 groups that center closest to the same point on the target represent your most accurate load.



The clever thing about this is that it transforms the problem from comparing group sizes, which is difficult (3:1 ratio in size does not indicate change), to measuring POI, which is relatively easy.



The physics and stats add up nicely. The problem is that 15 degrees F difference in barrel temperature easily exceeds the effect of adding another grain of powder. Still, it will probably help you find accurate loads for your rifle, expending no more than about 40 rounds or so.

Thanks for the great effort but maybe I need a book or an article to read...???? Maybe I can figure it out later.. thanks and feel free to expand , anyone.., thanks, Doc Stone I may be a dumbA$$

Someone posted this on the "Ladder Method" thread a few days ago.
web page

Thanks Paul, I've read the article now and am beginning to see the light at the end of the ---..target?? ha.. anyway great link and again thanx, Doc Stone

Hotcore., I now understand the technique.. thanks to you guys.. My problen is I don't have a place to shoot 300yds. off a bench.. Would 100yds. or 200 yds. be acceptable?? advise and expand:, you guys are great. By the way do you need any info on dentistry?? (I don't think so) ,Doc Stone

Doc, the distance is incidental. You can use 173.5 yards if you like. The idea of the greater distance is to make the shot pattern clearer. If I were to use the ladder method at 100 yards with my 22-250, I'd get a large ragged hole that would be elongated up and down and it would be very hard (impossible???) to determine where the shot cluster was. I believe the original method used a very tall narrow target with one aiming point. The shots would kinda wander up the target as greater powder charges were used. At some point, a few of the shots would fall closer together (cluster). That is the "sweet spot" for that powder. Now then, you reload shells using the cluster as the powder bracket and use smaller increments of powder and repeat the shooting part of it. And so forth. Then someone tells you, "you've got to try some xxx powder in that cartridge. Its much better than the one you're using." Then you get to start all over again.

[quote...........As we increase Powder at 100yds, the Point-of-Impact is often Lower than the previous shots. This is because we are shortening the barrel time. This causes the Bullet to exit the muzzle at a lower point in the Recoil Arc which is a completely different dynamic from the forces that cause the elongated figure " 8 ".

---

Thanks Hot Core. I wondered why my .300WM would shoot lower at 100yds with my hotter loads.

Of course heating up the barrel with additional shots works fine for target shooting but if you're using a gun for hunting your practice shots needs to be from a cold barrel to see how it's actully going to group in my opinion because the barrel is going to be cold when you make that first shot and the first shot is the one you really need to be on the money with. At the range I shoot one gun at a target and lay the gun aside and shoot something else for a while until it cools completely down and shoot again and so on to see if it's groups the same each time when cold. That's my 2 pennies worth for a hunting rifle or handgun.

5M

It's a load development technique, not a sight-in technique, in fact the scope adjustments are not touched during the entire string. So having the barrel at a warm/consistant tempature, as opposed to cold, is not a issue.
Once the load is fully developed, than switching over to "one shot from cold" sight-in is the norm for hunting weapons.