Ladder test works!

[257speed]

Many thanks to Abinok and the others for turning me on to the ladder test. Had to develope a load for my 257 STW using Ramshot Magnum and 110gn Accubond. Ladder tested 20 rounds at 400yds. Sure enough, two distinct sweet spots at low (3300fps) and high (3500 fps). Chose the middle load of the higher sweet spot and sure enough, shot a 1/2 moa group at 100 yds (first four in .290")at 3490fps. Load developement in less than 40 rnds! /ubbthreads/images/graemlins/grin.gif Gotta love it, especially with a barrel burner like the 257 STW.

 

[4ked Horn]

Cool beans.

I'm looking forward to trying it myself in the future.

So I take it that you shot a 1/2 MOA <u>5 shot group</u>? Good deal. The les shots for load development the more shots for critters.

 

[257speed]

Yes thats correct, five shots in .590".

 

[Kenster-Boy]

I am curious if you could BRIEFLY explain what a ladder test is? I think that I am already doing this sort of thing without knowing that it was a common procedure but just to be sure, what is it?

Thanks.

 

[abinok]

Glad to hear it worked for you 257. Next time you see somebody at the range knee deep in brass, with a frustrated look on his face, be sure to share!

7mm, the short description would be shooting a series of rounds, each with different powder charges loaded in increasing incriments of charge wt in an attempt to find vibration nodes that minimize the dispersion caused by varying charge weights, while allowing an accurate, repeatable load to be found for a rifle, with a minimum round count being fired. Ive got a document that does a passable job of explaining the ladder test. If you would like a copy, id be happy to email it to you.

 

[257speed]

7mmagman, check this out http://longrangehunting.com/ubbthreads/showflat.php?Cat=0&amp;Number=67743&amp;an=0&amp;page=8#67743

 

[257speed]

Abinok, I edited my post above with a picture of the results of the test, but I did not have any pictures of the ladder target. I wish I did because it was different than yours. Even at 400yds, the shots did not climb vertically very much. What they did do, is that they would be very erratic and then they would cluster, than get erratic again and cluster again. Out of the 20 shots, there were two distinct clusters at two different velocities. I chose the faster of the two clusters and then picked a load somewhere in the middle, which gave me the group in my previous post. All in about 27 total shots! I think at these distances, the 257 STW is shooting so fast/flat that there was not much vertical change.

 

[Sasquatch]

you beet me to it 257speed, if you want I can forward it to him abinok. I trust in it enough that I don't want to lose it.

I found sweet spots at about 2800 and 2900 fps using 150's in the .30-06. Had the same kind of experience as 257speed at 350 yards. Also found one at about 3300 fps in the 300 RUM using 180's. Thanks a Million abinok!!

 

[srhaggerty]

Abinok,

Could you email me the details. I have been frustrated on more than one occasion on load development. Still learning... [email protected]

 

[Kenster-Boy]

[ QUOTE ]
7mm, the short description would be shooting a series of rounds, each with different powder charges loaded in increasing incriments of charge wt in an attempt to find vibration nodes that minimize the dispersion caused by varying charge weights, while allowing an accurate, repeatable load to be found for a rifle, with a minimum round count being fired. Ive got a document that does a passable job of explaining the ladder test. If you would like a copy, id be happy to email it to you.


[/ QUOTE ]

Sure I'll take a copy, [email protected] Thanks

 

[abinok]

emails sent gentlemen.

 

[srhaggerty]

Thank you. I found it interesting. I will try it with my 25-284 in a few weeks.

 

[remingtonman_25_06]

could I get the full deal on the ladder test. I am going to test it out on my 300 RUM and my STW. I dont know I'f I fully understand it, so I was just going to shoot and take a picture of the target and post it on here to see what you guys thought. Thanks.

 

[abinok]

Remingtonman, I tried to email you the document, but got a delivery status failure. if you have a address other than that listed in your profile I can send it to, let me know. If you don't want to share it publically, email it to me.

There have been a few pictures of ladder test targets posted here before so you can kinda figure out what you are looking for. A link to one of them was provided by another member earlier in this thread... but im sure if you post a pic of yours, you wil get some opinions.