Texas Hunting Forum

Ladder test article

Posted By: TackDriver

Ladder test article - 09/06/17 01:56 PM

For those who like to read about ladder testing. Good article.

http://www.65guys.com/10-round-load-development-ladder-test/
Posted By: patriot07

Re: Ladder test article - 09/06/17 03:44 PM

Interesting article. One point of discussion:
Originally Posted By: article
The following quote from Scott summarizes a key observation with load development, “Im not sure it is optimal charge weight at all but optimal velocity for the bullet weight that determines barrel harmonics. The reason I say this is because I can get the exact same great results in a velocity node using seven different powders. As long as I keep the bullet going the same velocity from powder to powder I get the same result. Powder charge may be slightly different but as long as I’m in the velocity happy place for that bullet and my cartridge, powder is secondary.”
This has not been the case with my Tikka Varmint 223. My optimal summer load with CFE223 shoots faster than my optimal winter load with CFE223. My optimal load with Varget shoots faster (and not quite as tight) as both CFE223 loads. There is about 150 fps difference between my summer CFE223 load and my Varget load, but both shoot 1/2" groups or smaller. My CFE223 load that matches varget speed-wise is awful, and my Varget load that matches CFE223 speed wasn't very good either.
Posted By: J.G.

Re: Ladder test article - 09/06/17 03:48 PM

Ladder Tests work, plain and simple. They save time, and components, and barrel life especially on the barrel burners.

I have found a terrific load in a mere 9 shot ladder test, followed by a 5 shot group, and was done. That's only 14 rounds fired. Then obtained DOPE on that load from 200 to 800 yards, then let the barrel cool and run the range again.

But unlike what they are speaking about hunting velocity, I am paying attention to where bullets land in relation to each other. When they're not loaded the same, and are grouping sub MOA, that's the node. At the tail end, I find they do in fact have a low ES, when I finally do chronograph them. So I'm not saying he's wrong, we are just approaching it from a different direction. I will not have a Magneto Speed attached to my barrel during testing. I don't care how light they are, they weigh someting, so they're changing barrel harmonics, for all but the heaviest contour barrels, like an MTU contour.

The cartridges I've performed ladder test on:

.223 (bolt action)
.223 (AR)
.22-250
.243
6.5 Creedmoor
.260 Rem
7mm-08
.308 Win (bolt action)
.308 Win (AR)
7 Rem Mag
.300 Win Mag

Every single cartridge worked well with a ladder test.
Posted By: dee

Re: Ladder test article - 09/06/17 03:52 PM

I've done that method before with good luck. Can't say I gotvthe idea from them though. Sat there one night looking at my magneto and decided to try it.
Posted By: TackDriver

Re: Ladder test article - 09/06/17 07:14 PM

I did 5 ladder tests the last 6 load developments, all 5 is shooting excellent groups of half an inch to less than an inch at 300 yards ( Accubonds, Ballistic tips and SMK) except for the Long Range Accubond. I replaced it with the 160 Accubond which did outstanding. I have stopped shooting 3 round groups during load developments, waste of bullets and time. Ladder tests have been much more efficient and saves time, not only that, gives my barrel burners a longer life. I changed my tactics because of Fireman's successful tests. up
Posted By: J.G.

Re: Ladder test article - 09/06/17 10:10 PM

up
Posted By: Walker_clint

Re: Ladder test article - 09/28/17 05:46 PM

Just watched the video posted while ago, my question is, whats considered a good standard deviation? Maybe I should rephrase, what's an acceptable SD?
Posted By: stxhunter

Re: Ladder test article - 09/28/17 06:12 PM

Typically what distance do you do the ladder test at? Do you use a sharpie to color the tips of your bullets to keep track of shots?
Posted By: dee

Re: Ladder test article - 09/28/17 06:15 PM

Originally Posted By: Walker_clint
Just watched the video posted while ago, my question is, whats considered a good standard deviation? Maybe I should rephrase, what's an acceptable SD?


Ideal imo is sub 10 but I've not been overly concerned if in the 15 area. My current match load is in the area of 4 for 10 shots. I do believe some case designs allow for lower sd than others so it's something to keep in mind.
Posted By: dee

Re: Ladder test article - 09/28/17 06:16 PM

Originally Posted By: stxhunter
Typically what distance do you do the ladder test at? Do you use a sharpie to color the tips of your bullets to keep track of shots?


Minimum of 300yds. Sharpie trick is the easiest way if your glass isn't good enough to see impacts.
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