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Load Development... Ladder Day Revelations???

 
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Old 03-06-2007, 12:12 PM
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Load Development... Ladder Day Revelations???

I've noticed a lot of talk about "shooting ladders" to aid in load development. I have done this a time or two in the past, but it has never been an effective method for me. Much like Catshooter has stated so well on another post... the statistical evidence of anything is often hard to distinguish. Also, I'm not concerned about a load that creates a "node" with sub-par velocities, I'm looking to get the most velocity I can out of my particular chambering... then I'll go get the accuracy I require. I'm not trying to bash the ladder method... it's just a little too complicated for me and I'm just curious what other methods of load development some of you other guys on this forum use.

This is what I usually do:
-I start by selecting a bullet and 3 appropriate powders (ie... RE-22, H4831, N560)
-I then load 3 rounds with each powder at 4 different charges up to book max (ie... 54.0,54.5,55.0,55.5)
-I fire these at 200 yds over the chrony for velocity (and all the byproducts... ES, SD, Avg. MV) and simply make note of the accuracy. Any load that shoots over 2" @ 200 is thrown out... I'm looking for a load that "wants to shoot".
-After I know the fastest I can safely load each powder, I use that load and move the seating depth around by +/-.005" until I reach acceptable accuracy levels.

I've found this method of load development much easier and more effective than shooting a ladder. This method only requires 36 rounds to complete, and I have always found a load that provides maximum velocity with excellent accuracy... even out of factory guns. It also allows for some fine tuning of OAL to maximize accuracy. I noticed when I shot a ladder, then adjusted seating depth the results of the ladder changed drastically (anyone else ever try this?).
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Old 03-06-2007, 01:34 PM
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Re: Load Development... Ladder Day Revelations???

My normal procedure is to pick the powders by browsing the manuals and I pick the powders that gives the fastest velocity with a full case - anything slower is a waste of time.

A this point, I have the "group" of powders that are suitable. Then I look at powders that are faster.

For example, if a round shows 4064 as the highest velocity with a full case, it means that 4895, Benchmark, Varget, 4007, W748, etc will ALL be suitable powders.

If it is a rifle that is to be used under shade trees and out in the baking sun, I will avoid ball powders because of the temperature problems... this leaves me with Varget, BenchMark H-4895, etc.

Then I load up a bunch of new cases, in 5 round batches, with spacing of about 1% (0.2gr for 20 to 30 grain cases - 0.5gr 40 to 50 grain cases - 1gr for belted magnums).

Then I shoot them for velocity and group. I repeat the good ones again.

I might try two or three powders, so I have run 200-ish loads by the time I have found the one I like.

If it's a round that is rough on barrels, I take a different approach.

I just got a .264 Win Mag, and started loading for it in November.

I did the powder choosing like above and decided on H-4350, and H-4831SC.

In this case, I loaded 2 cases of each load. It was the minimum that would give me a "hint" of what I was looking for, cuz I didn't want to spend 300 rounds of the barrel life finding a load.

Now... two shots give you a better look at the load. First, statistically, you "might" get the two slowest rounds of a hypothetical 5 shot batch, but with two shots, that's only a 20% chance.

But more important, you get a good idea of what's NOT a good load.

If you shoot a 5 shot group, you will generally have two that are close, maybe even touching... and the other three scattered out to make the group size... you have had them... 1" with two touching.
If you shoot a two shot group, you DO have a chance of catching those TWO touching rounds... but it's a 20% chance.

But more importantly, with those two shots, you have an 80% chance of catching two of the NOT touching rounds.

So in effect, this is a fast way of elimination BADD loads quickly, and getting a fair indication of velocity. So two touching rounds MIGHT be the beginning of a good load, but two shoots ONE INCH APART is definitely a REJECT!

In this way, you can do a "process of elimination" with minimum rounds expended. Then you take the best of the "two shot groups [img]/ubbthreads/images/graemlins/wink.gif[/img] " and repeat them.

Turns out that the .264 barrel is excellent, and ALL of the 2 shot groups were touching or overlapping, so by expending 40 rounds I had a damn good idea of what my next tests were going to be, and what my velocities were going to be.

Now... which of those loads will be the best I don't know... but I do know that in that bunch, there will be a very group, because... if it's a 20% chance of getting a "best two out of five" in a two shot group, then the chances of that happening five times in a row are 0.2 to the 2.5 power... which is an itty bitty number.

So I have a winner, and it'll take me another 40 or so rounds to pick a group, and then I'll load up the whole 200 cases and be done with it. But this time, I'll do 5 shot groups and fire at 400 yds, cuz I know that all the groups will be on paper.

I hope that this makes sense...

.
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Old 03-06-2007, 01:44 PM
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Re: Load Development... Ladder Day Revelations???

[ QUOTE ]
... Any load that shoots over 2" @ 200 is thrown out... I'm looking for a load that "wants to shoot".
-After I know the fastest I can safely load each powder, I use that load and move the seating depth around by +/-.005" until I reach acceptable accuracy levels.

I've found this method of load development much easier and more effective than shooting a ladder. This method only requires 36 rounds to complete, and I have always found a load that provides maximum velocity with excellent accuracy... even out of factory guns. It also allows for some fine tuning of OAL to maximize accuracy. I noticed when I shot a ladder, then adjusted seating depth the results of the ladder changed drastically (anyone else ever try this?).

[/ QUOTE ]


First of all for 25 years, I used a method similarly to yours and always found a load that was good enough for my purposes. Lately however I've been using the ladder test method and only wish I had heard about it sooner. I've only used the ladder test a few times, but every time, its been very helpful in finding an excellent load.

1) what level of accuracy are you looking for? 2" at 200yards is only 1MOA, I've shot entire ladders that shot sub 1MOA for every 3 contiguous shots, the lack of velocity spread is the real story. If I shoot a ladder and find a 'node', I am confident that load will tend to be somewhat temperature immune. It is my belief that a load that is less sensitive to its exact powder volume will also be less temperature sensitive as well.

2) With the exception of reduced loads, my rifles shoot nearly every load I've tried at less than 1MOA (handloads as well as factory loads). Using your method and an accuracy standard of 1MOA, would lead me to just select the highest velocity every time. In that case, you don't even need a 3 shot group, just run a ladder to find the highest pressure load and go for it. Shooting a few 3 shot groups that all shoot sub-MOA, doesn't tell me anything about how that particular load or lot of powder will perform. I would have no idea whether it was a great load or just an average load that happened to shoot well a couple of times.

3) You are moving the seating depth around by .005", thats an awful lot. I usually shoot groups at every .001" to find the sweet spot ( I verify with a digital mic to the ogive ). In almost every case, close to the lands seems to work best, and thats where I start when I do the initial ladders.

4) When I perform my ladders, I also sort my brass by water capacity, so all loads are burning in the same size chamber. Here is an experiment you can do, take 100 brass and weigh and sort them heaviest to lightest. Now work up a load with your heaviest brass (smallest capacity cases) and then shoot that same load in the lightest (largest capacity cases). The load will almost certainly behave differently, lower velocities etc. In my personal experience, shooting a ladder with random case capacities just adds noise to the results. Maybe the reason that some very competitive types swear by the ladder method is their brass consistency. Maybe those that use very uniform/consistent brass have better luck with the ladders, because the data is easier to see. And maybe some of those that have bad luck with the ladders just have too much noise in the experiment to see the useful data???

5) Since this is LRH, I'll assume that you are going for higher velocity to flatten your trajectory. For my 7RM, a difference of 25fps at the muzzle translates into 5" at 1000yds. I'd much rather have a load that was 2950fps with an extreme spread of 25fps (across temperature variables) than a load at 3050 with an extreme spread of 40fps (across temperature variables). The 2950 load would be more apt to be on target with a spread of 25fps than the load with a little larger spread and 100fps more muzzle velocity. In my book, minimizing extreme spread is 'where its at' when you start talking long range. The more consistent 2950fps load will vary 5" at 1000yds due to initial velocity variance, the faster load with a higher spread will vary 8" at 1000yds due to initial velocity variance.

The ladder method is the only means that I'm aware of to find the MOST consistent load available for long range usage.

Ladders have worked like a charm for me.

Later,
Don
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Old 03-06-2007, 02:52 PM
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Re: Load Development... Ladder Day Revelations???

I hear you Don, consistency is the key. I've noticed, however, that on my ladders (as well as many I've seen posted here) the "nodes" are usually a lot further apart than 25fps... more like 150-200 fps. I do agree that minimizing extreme spread is paramount. Also, I don't just settle for MOA accuracy. Once I figure out which load produces the highest velocity with the most consistency I further develop the load to .5-.75 MOA. That's about as good as I can expect sporting type rifles to shoot... good enough for a coyote or Mule Deer out to about 1/2 mile or so!
As a side note, I wonder what would happen if you shot a ladder with the same powder charge and moved the seating depth around? Say... .002" per shot for 12-15 shots. Has anyone done this? Maybe I'll give it a try and post my results... as soon as I spend a day fireforming some 25-06AI brass.
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Old 03-06-2007, 03:04 PM
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Re: Load Development... Ladder Day Revelations???

RE: chrono assessment of velocity spread.

most chronograph setups out there are not accurate enough to give you a statistically signifigant number.

i.e.: Chrony chronographs will err +-15fps on a 3000fps load with 1-foot spacing.

Oehler 35's on a 2,4,8 ft rail are better but to get REAL numbers accuracy needs to be +- a couple fps...

YMMV,
JB
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Old 03-06-2007, 03:43 PM
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Re: Load Development... Ladder Day Revelations???

[ QUOTE ]
RE: chrono assessment of velocity spread.

most chronograph setups out there are not accurate enough to give you a statistically signifigant number.

i.e.: Chrony chronographs will err +-15fps on a 3000fps load with 1-foot spacing.

Oehler 35's on a 2,4,8 ft rail are better but to get REAL numbers accuracy needs to be +- a couple fps...

YMMV,
JB

[/ QUOTE ]

Obviously if the chronographs where perfect, that would be better, but they aren't. In my opinion though, measuring velocities (even with a +-15fps error) and using that WITH target information is better than using target information only. A 15fps velocity difference is going to show up as only 1/10 MOA on target.

Given a large enough sample size with a known 15fps error, you can still come to conclusions on actual statistically relevant spreads. I'm not good enough to read anything at the 1/10 MOA level from a target though.

Where did you get the 15fps spread info? A good way to test it would be to shoot through 2 chronos at once. Then compute the average deviation of their differences. If someone has done this, point me at the information. It might be a nice experiment to try this summer.

Don
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Old 03-06-2007, 09:58 PM
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Re: Load Development... Ladder Day Revelations???

Cat, I do the same thing like you do, and I always find the load I'm looking for. What I found out though is that, it is easy to find a good load for a custom rifle than on a factory rifle. Comparing data from 3 or 4 reloading manual as reference, I usually find my load with just a few trip to the range, with very minimal effort and waste of components.
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