The Accurate Reloading Forums
Ladder and Lands Questions
29 November 2010, 02:15
FMCLadder and Lands Questions
I've read some interesting things today and would like to learn more.
I've never used the ladder technique but it sounds interesting. Does barrel warm up come into play when you're doing a string? Does it matter at all? Or does it matter more in the second ladder (load sweetspot) than the first (rifle sweetspot)?
Second, I've always tweaked loads going towards the lands as the final adjustment. But I read if you work your load up from the bottom (ie the correct way) it's "better" to start with the bullet in the riflings (of course looking for pressure signs) and then when you find the sweet spot, adjust the jump "off" the lands rather than towards.
Any thoughts?
(I don't usually have the time for a comprehensive load work up. My way to work up a load has been to pick a velovity, get 2-3 powders and go from there. I use TSX so I do start with a jump and diminish it as detailed above)
There are two types of people in the world: those that get things done and those who make excuses. There are no others.
01 December 2010, 18:11
243winxbHunting loads do not start with the bullet jammed into the rifling. You TSX bullet needs to jump starting .050" off lands. From there you can make adjustment as you have. Not sure what "ladder" is? I set the base of the bullet at the neck/shoulder junction and work up the powder charge from the starting load, to near max. Then retest with what looked good on target. Barrel heat is always a problem if your barrel walks the bullets. Some do, some dont. Getting the round centered in the chamber is important. Controling shoulder bump on sizing is important.
01 December 2010, 18:28
Jim C. <><quote:
Does barrel warm up come into play when you're doing a string?
The method of testing doesn't matter, any "groups" fired from a hot barrel only tells us what a hot barrel will do.
It's not particularly better or worse to start anywhere with ladder seating/OAL tests but it is perhaps easier to accomplish if we start by seating off by maybe 20 thou and then back off more in steps after finding a potentually good charge.
01 December 2010, 19:19
BriceI invented the ladder method, only to learn that David Tubb had invented it several years previously. (I had a couple of courses in statistics in grad school.) It is a very efficient approach and greatly reduces the powder, shot and time required to find a decent load. Here's my method:
-Design two load sequences, using two powders. Select powders that usually work well in your caliber. They should not be too close on the burning rate chart. You will find such a chart in some loading manuals. You might want to use one ball and one stick powder. Begin at or near the manual's suggested starting charge weight. Increase the charge approx. .5%, around 1/2 half grain for each round. Less for a 223, more for a 458. Use the same bullet, primer, seating depth for all. Remember, you can only test one variable at a time and still get reliable results.
-I use the diamond shaped orange sight-in targets for this purpose. They have a one-inch grid pattern, which helps in locating shots. Have your spotting scope near the bench so you don't have to move. Have a second target, which can be a photo copy, on the bench. Mark each shot with a small circle and a sequence number. Take you time and don't let the barrel overheat. If the barrel has been cleaned, take a couple of fouler shots first.
Retrieve the target and enter the sequence numbers. I have never shot a ladder that didn't give me useful info. Your brain will do a good job of seeing the group tendencies.
243winxb is correct regarding Barnes bullets at 050. He is also correct about hunting loads and seating depth. This is due to pressure and reliability issues. Except for Barnes, I usually start at around 020 off the lands, like Jim C. You can test seating depth adjustments with later ladders.
If you have questions hit Reply or PM me.
01 December 2010, 19:58
Jim C. <><quote:
Brice: I invented the ladder method, only to learn that David Tubb had invented it several years previously.
Actually, a military ballistican/shooter named Creighton Audett developed it long before Tubbs came on the scene.
I sometimes do a ladder variation by shooting two shots of each step at individual targets numbered for that charge. That helps a little but not a lot, the original plan works fine.
01 December 2010, 23:23
<Andrew cempa>The beauty of the Audette Method (Ladder for short) is that it not only shows you where the harmonic nodes are, it allows you to select the optimum load (not necessarily the "tightest" group) range of both velocity, powder consumption and POI.
I find that with NM rifles, the ideal load range is often in the middle of the node clusters, not the fastest, not the slowest, but the one that allows the minimum sight setting to facilitate across the course elevation settings w/o running out of elevation.
Once I find the starting node I want, I then repeat using different OALs, always measured from the original load seating depth. Then, repeat the trial and note the best node once again. This will usually provide a load that will hold the 10 ring (or better) at 600 as long as you do your part, while allowing a low 200 yard setting and a lower than commonly found 600 yard setting.
The best aspect of this process is that it uses less ammo in development and therefore wastes less barrel life.
My norm for this process is 16 rounds max, eight for powder and eight for OAL, sweet spots are normally very obvious.
Lastly, the functional benefit is not having to worry so much about "perfectly" measuring powder (I throw all loads nowaday-200 to 600) or case prep/seating depth, as we found the "best" compromise among both-which is impossible to otherwise avoid-machines are not perfect.
01 December 2010, 23:41
BriceWell, you learn something every day. Thanks, Jim C. I didn't mean to deprive Audett of the deserved credit. Plus, I learned some more about ladders. Ain't this a great forum?
02 December 2010, 05:35
FMCThanks for the responses. Me being anal with reloading am always loking for a better mousetrap.
Again I read about it on a different forum on working up a long range load. Perhaps that is why the gentleman suggested .010 into the lands and then backing out- I've always played with lessening the jump as a final tweak.
Do both ladders at 300 yards then?
Kinda tough to shoot 10 without warming it up though.
There are two types of people in the world: those that get things done and those who make excuses. There are no others.
02 December 2010, 16:31
TC260I always start with the bullet closer to the lands for the initial load work up and then increase the seating depth to see if that improves accuracy. I usually start at .010-.020 off the lands and I've found that's plenty close enough for hunting applications. In competition shooting where everything top to bottom is precision built and tightly controlled seating the bullet into the lands is fine. It can really increase pressure though so for hunting gear the risk is high and benefit is minimal.
02 December 2010, 20:02
243winxb300 yds seems a bit much for the average guy/rifle. I would guess it works with custom barrels, using high power scopes, with an experenced shooter, if the conditions are good. Little to no wind. I will have to give it a try next spring.
Is this the correct ladder test? http://www.desertsharpshooters...nuals/incredload.pdf03 December 2010, 22:47
The SpartanHas anyone tried the Dan Newberrys Optimal Charge Weight Load (OCW) method of load development?
The OCW involves shooting up to 5 groups of 3 rounds and looking for the three groups which come the closest to hitting the same POI (point of impact). This will be a very "pressure tolerant" or "resilient" load. When the pattern is identified tweaking (seating etc. begins). See
http://optimalchargeweight.emb...tructions/4529817134 for How-To details and the theory behind it is also on that website.
I have tried both the Ladder and OCW for developing hunting rounds and prefer to use OCW although it generally requires more shots to arrive at the ideal/durable load for each barrel/gun.