Ladder effect

[trobin]

Does anyone use this? Pros and cons please...

[wogpotter]

Do you mean working out a new load with ladder loads for interpretation for intermediate charge weights?
If so then yes I do & yes it works well.

[histed]

+1 with Wogpotter. The up side is that 1) you can see kow the load is progressing (tightening groups, pressure signs...). The downside is that you can burn a lot of powder and use a lot of bullets in a hurry. No problem in "normal" times, but... I usually work up in 1/2 grain jumps for rifles and .2 grain for handguns

[tpcollins]

If you shoot the ladder affect, do you shoot at 200 yards? I thought I read somewhere it needed to be that far to be effective - but I don't know for sure.

[ricklaut]

When I developed my long distance load for my .308 Savage, I did ladder testing based on a thread on Snipershide. Outstanding results... and yes, I did it at 200m. I don't think I could have interpreted the results if I'd tried it at 100. In fact, I'll probably try 300m next time.

[trobin]

I was told to work a load and increase by .3 grain. Shoot all rounds (one of each) at 100 yards using same point of aim. Rounds should rise with each shot. Once I have three hits grouped together (ie 40.3, 40.6, and 40.9) I should use the middle load (40.6) as a starting point to fine tune.

[ricklaut]

I started with .5 grain separation between loads and then, based on those results went to .3 grain separation. I based what I did on this thread http://forum.snipershide.com/snipers...-powderin.html and others in his series.

Not all the holes on the paper will rise as the charge weight increases. The barrel is flexing ("whipping"), so depending on the node, at a higher charge, the barrel might be on the low side of the whip when the bullet is exiting. But yes, you're looking for several that group together and fine tuning from there.

[hooligan1]

Working up loads in 100 yd ranges does'nt have to be rocket science, however once I start load developement I put on the ole labcoat.
Dan Newberry's OCW system is the way to go, if you have a range that will let you engage multiple targets. The targets I can use at my range are pretty standard "sight in" targets, and it makes shooting the OCW a little tricky,, not impossible just tricky.. But I think if you tried it you might find you'll like it.

[tpcollins]

ricklaut - the ladder test I read awhile back was using .1 grain increments ( 20-21 different loads) and least at 200 yards. I wonder how many "different ladder tests" there are? I usually use the OCW round-robin type at 100 yards, I don't have any place to shoot 200 yards from a solid rest.

[wogpotter]

I'm thinking of a very different technique for "Ladder Loads", one that uses less powder & supplies, not more!

Here's the technique I use.

1: Get several manuals with the powder/bullet combination you're thinking of.

2: Find the LOWEST high load.

3: Find the HIGHEST Low load.

4: Find the median (1/2 way between (1) & (2)).

5: Load 3 batches of 5 rounds. #1 is the HIGHEST LOW, #2 is the middle of the road, & #3 is the LOWEST HIGH.

6: Fire & chronograph all 15 loads.

7: Graph the resuts.

Because you set up a max/min/ median you've created the strait line portion of the volume/pressure/velocity curve. Just pick a desired velocity, or load, & look it up from the graph. make up a set of 3 lets say aim, aim +2%, aim -2% & shoot to fine tune & you're done!

[snuffy]

The only ladder test I ever used was to stand it against the barn, jump on it to see if it fell apart!

I just never could wrap my mind around the validity of that method. For one, you have to track each and every shot. AS YOU SHOOT THEM! (Expensive spotting scope). Two, you have to have a very stable bench and spend some money on a good rest and bags. Three, good shooting conditions. Four, having a range with no interruptions, like a curious bystander to interrupt your session-------. Five, a target stand that will not move in the wind. No off the hood of a car, or over a rolled up jacket. Six, a rifle that has inherent accuracy. Meaning it can shoot good groups with either factory rounds, or good handloads. Seven, a good scope of high enough power to see the aiming point clearly. My way of saying it is; if the scope didn't cost about what the rifle cost, then you don't have a good enough scope.

Here's a discussion over on the AR forum;

http://forums.accuratereloading.com/...271#5771015271

Especially Larry Gibson's take on it:

"Unfortunately pundits would have us believe it is the end all method for general load development. It is not.…

"Reason is even though those shots may hit close together with such a wide variation in velocity at one range the velocity ES will eat you up with large bullet drop at longer ranges.…"

{Edit for board copyright policy}

Then there's Dan Newberrys bastardization of the Audeette method called OCW, Optimum Charge Weight;

http://optimalchargeweight.embarqspace.com/

Do whatever you want, it's still a somewhat free country. To me, it's a waste of hard to get components.

[wogpotter]

For one, you have to track each and every shot. AS YOU SHOOT THEM!

Actually you don't, all you do is chronograph them for velocity, spread & SD. The ladder sets up a desired velocity, accuracy comes from where you use that data for an "accuracy" load.

The second test where you shoot the 3 X 5 round groups is where you see if your groups print as well as the thoery says. All you do then is shoot for group, just as you would anyway & pick the best set.

[Unclenick]

The way the original Audette Ladder works (scroll down to second half of this page) you have to know which hole was made by which load in the string. Often there is scatter due to velocity spread, as Larry Gibson suggests, but with some math you can get past that. Here's an example of a 17 shot Audette Ladder fired at 325 yards that I did an analysis for someone on. He describes it in the first post and I worked on it for post 13. By the end he had a tight load.

[Dan Newberry]

Here's a link to my discussion about what I call the "scatter node", which is why I believe the ladder test so often fails to lead the shooter to the correct conclusions.

http://optimalchargeweight.embarqspa...der/4529811360

The OCW system is about finding a great load in as few shots as possible. With component costs and availability being the issues they are these days, the old "hunt and peck" method of load development is--unless one just gets quite lucky--an expensive way to go.

Dan

[Dan Newberry]

Uncle Nick... excellent job on discerning that ladder. It can be done, as you've shown. That method has worked for years for many. My post above wasn't to cast dispersion on the ladder method outright--or your ability to read it. I was simply hoping to illustrate what I believe to be the reason why the ladders don't give good results (when they don't, that is)...

Dan

[Bart B.]

Some folks not trusting ladder tests have done something else that I think is better. The start with powder that produces the least amount of velocity change per 1/10th grain of powder.

Using Sierra's load data (or any other with muzzle veocity in 100 fps steps), calculate the fps change per 1/10th grain of the powders listed. Pick the powder with the least change per tenth, then use that powder to start with. This is one reason why ball powder charges of exact weights typically don't shoot as accurate as extruded powders with a 2/10ths grain spread.

Depending on the inherient accuracy of a given set of components for the barrel used, it may well put a given charge weight's bullet lower on the target than one with 1/3 or 1/2 grain more.

And the velocity spread of a given load may very much overlap the spread of one a bit heavier or lighter than it. This can be seen by plotting a graph of charge weights vs 100 fps increments for a powder then looking at the velocity spreads they produce.

And the shooter's skills will also be reflected in the downrange results.

[gwpercle]

The ladder effect...When the wife gets out the ladder the effect is sombody is going to have to paint something up high. Chances are good it will be me.

[pathdoc]

Bart B, that sounds like an interesting method.

Coincidentally, I happen to have Hornady's 7th Edition reloading manual to hand and I flicked through it to see if anything had some nice round numbers that I could work this method over with in my head. 150gn bullets in the .303 British fit the bill - IMR3031 gives a 100fps per 2 grains rise between 2200 and 2400fps. The next jump, to 2500fps, demands 2.1 grains and then to 2600 (the maximum load with this powder) is 2.0 grains again.

So there's a possibility that rounding errors could screw with you. Let's assume, however, that the effect is real and look at some others.

Comparing another powder for the same cartridge and bullet, we find that Varget has a two grain jump from 2200 to 2300fps, then 1.9 grains from 2300 to 2400, another 1.9 grain jump from 2400 to 2500fps, and again a 2 grain difference from 2500 to 2600fps, whilst RL-12 has 1.9 grain jumps all the way up, except for the jump from 2500 to 2600fps, which is 1.8 grains (which those who chase velocity might leap upon with eagerness).

There are others, of course, but looking at just these three (so as not to become exhaustive) it would seem I should reach for the ReLoder 12 as my first choice all round. The question I have is that the method you recommend seems to imply I could get as good a result in the middle range between 2300 and 2500fps with Varget as with RL-12. And what are we to make of RL-15, which alternates between 1.7 and 1.8 grain jumps per 100fps all the way up to maximum?

Wogpotter, your method also sounds interesting but there is the issue of finding those multiple manuals. Taking Hornady bullets again as the example, one of those manuals would obviously be the Hornady Handbook. I'm imagining another might be the Lyman and others possibly the powder manufacturers' guides?

[Dan Newberry]

reloder 12 has been discontinued for some years now, unless they've brought it back unbeknownst to me...

3031 would be very close I'd say...