Ladder test for .338 Lapua, need help.

[Tango down]

Hi

A friend of mine and I are getting ready for a ladder test with 300 Berger OTM and H1000; our rifles are SAC .338 LM and Sako TRG 42, 338 LM. We have some experience but never done a ladder test before, so this was the plan.

We were going to shoot at 300 yards, 3 strings of 14 bullets per string, powder from 84 gr to 91.5 gr, .5 increments, were going to seat bullets at manual specs. Were going to shoot 1st string from high to low, 2nd string low to high and 3rd string high to low.

Now we are finding out that we may not be doing this right, so we do have questions.

Is 300 yards too close? Should we go to 400, 500, 600?

Are 14 bullets per string enough? Are 3 strings enough?

Should we go by .5 increments, or .3 increments? Does it depends on how far we are shooting?

Should we seat the bullets at manual specs, or, as they are Berger (OTM less sensitive to seating depths than VLD, so not sure), should we seat them at .02 off the lands, in order to have a better idea?

We would like to do this right, so thanks for helping.

Good shooting to all.

 

[joemusso]

i have a TRG-42 as well i would like to know the right way to do a ladder test.
please post your results. i am using the same powder and projectile.

joe

 

[oneshot.onehit]

With the case volume of the 338LM, use 1 grain increments, The distance all matters on your skills, I ran most of my testing at 600 or 700 yards

 

[Xtremegunnr]

.5 increments are fine. I mean...will you see major differences..maybe not. you are gonna be good between 88 and 92. I wouldnt go lower. it will waste bullets and time. Load to mag length with the trg. Check the throat on that sac with hornady oal gauge OR load them both the same length (according to trg mag). My Trg likes 91. most trg shooters like 90 to 92. My dta srs on the other hand likes 95 grains of retumbo at 3.925 inches. Every gun is different. Shoot at 300 + not more than 700 in my opinion unless you have very little wind. Both should shoot .5 - 1 moa at 1000 or you might wanna tweek.

Also, the otm might be too long for the trg. They work ok but they are far from the lands.

Hope that helps some

 

[Desert Fox]

Why not just tried using the recommended load above and be done with it. It seems like they're proven load.

 

[Tango down]

.5 increments are fine. I mean...will you see major differences..maybe not. you are gonna be good between 88 and 92. I wouldnt go lower. it will waste bullets and time. Load to mag length with the trg. Check the throat on that sac with hornady oal gauge OR load them both the same length (according to trg mag). My Trg likes 91. most trg shooters like 90 to 92. My dta srs on the other hand likes 95 grains of retumbo at 3.925 inches. Every gun is different. Shoot at 300 + not more than 700 in my opinion unless you have very little wind. Both should shoot .5 - 1 moa at 1000 or you might wanna tweek.

Also, the otm might be too long for the trg. They work ok but they are far from the lands.

Hope that helps some

Xtreme
Good info, we are collecting data in order to get this right. What is the barrel twist on your TRG 42 and what bullets does it like?
Thanks

 

[CK_32]

Sounds like you have it.


Ladder testing is basically at 300 or more yards and you shoot strings and find a cluster where a couple grains impact close to each other vertically.

With 308 300 yards is a good range. If you can go farther go for it you'll see more clear results but stay with in your skill limits. I'd say for 338 300 to 600 is a good range.

For my 308 what I do is load from book minimum to a few grains above listed max. Prefer to have more than I'll shoot than not find pressure signs and run out of ammo.

I do 2 strings personally and get shooting then go down range and see how it turned out.

 

[woostri]

I've never been able to get repeatable results at 300. 4-500 was more clear to interpret but that was with 6mmAI so I can see how .308 might show results at 300. There has to be enough drop to start showing statistical variences.