Wanted to Share a Ladder

[mikegaiz]

My opinion, a ladder test is used to locate barrel harmonic nodes, not to find best load. I start off my process using a ladder test at 300 yds. I have found if I don,t find a node (as shown in Picture in Ladder test below) the bullet powder will not shoot in that barrel. I then develop around the node looking for groups and Velocity/SD. (Node are Loads shown #7,8,9,10) With 4 to 5 shot groups at 300 yds, This ladder test provided me with an IBS record setting load.

 

[500Stroker]

Yes, something did change.. (temp) it was a tad warmer and it will be even warmer today! bbl was not cleaned.. nor will it be today either till this next test is done.

I did have a thought this morning though, when i was trying the Winchester brass (to which i ended up sending it all back to Winchester), it appeared that the working seating depth was 10K off the lands. Right now i am at 5K off, do you think that with the Lapua brass, that i should go back to that seating depth or stick with where i am at right now?

During your ladder testing keep the seating depth the same. After you finalize the results of the ladder and you have the powder load that you are going to shot then refine the load by adjusting the seating depth, follow the recommendations for seating in the Berger book they work well.

 

[BountyHunter]

shoot the ladder across a chrono too. You will find your target nodes tend to match your MV nodes also. You will see big jumps on MV then tighten up when you hit a node on the target then make big jumps again.

 

[USMCDOC]

shoot the ladder across a chrono too. You will find your target nodes tend to match your MV nodes also. You will see big jumps on MV then tighten up when you hit a node on the target then make big jumps again.

Don't own a chrony at the moment but i would do that if i did

 

[USMCDOC]

The 24.6 to 25.0 proved to be not working either.. Now to try it again.. with a different primer..

 

[mikegaiz]

Try a different bullet. Some bullets will not shoot in some barrels, no matter how many test you run. That is what is so good about ladder test. I tried 3 different 6.5 Berger ( 120, 130, 140 HY) with group testing, no luck. then I ladder tested the all Berger 6.5 bullets with ladder test and only found one that shot well ( good node) in my gun. and then ran group test to verify. That is what sold me on ladder test.

 

[USMCDOC]

Ok.. just come back from another test.. 100 Yard OCW for seating depth..

Lapua brass, neck turned to .247 OD

Load: 26.5 grs 2000MR, the reason that i chose this is, that this load was a working load with the Winchester brass i had.. but the primer pockets were too large in that brass.. it was leaking with even moderate loads.. sent it all back to Winchester.

Seating started at Base To Ogive of 2.0335 and finished at 2.0635 (ten in).. best group was with 2.0485 (5K off.) So i will be trying this load at a greater distance sometime soon!~

i don't have a chrony, but the 26.5 gr load was tested with a M.S. V3 with the Winchester brass.. Ave was 2811 with a SD of 7

 

[Link]

My opinion, a ladder test is used to locate barrel harmonic nodes, not to find best load. I start off my process using a ladder test at 300 yds. I have found if I don,t find a node (as shown in Picture in Ladder test below) the bullet powder will not shoot in that barrel. I then develop around the node looking for groups and Velocity/SD. (Node are Loads shown #7,8,9,10) With 4 to 5 shot groups at 300 yds, This ladder test provided me with an IBS record setting load.

Could you please tell us what load you ended up using out of 7-10?
Forgive my ignorance, why the uneven numbers. I would assume that is powder weight however it could be OAL?
What was your procedure after the ladder?
thanks Link

 

[spitfire_er]

You've got some good feedback so far, I just wanted to mention when shooting a big group like your initial test, group your loads together and use a highlighter or a marker to group your charge ranges together. Things usually become far more apparent visually.

 

[mikegaiz]

Could you please tell us what load you ended up using out of 7-10?
Forgive my ignorance, why the uneven numbers. I would assume that is powder weight however it could be OAL?
What was your procedure after the ladder?
thanks Link

Not sure what you are referring to "uneven numbers"? each shot in the ladder test is .5 grains higher in powder than the one before it. The picture shows load # and velocity, I think my final load was #8. I follow the ladder test with group test of loads 7 through 10. then I do a group test only changing seating depth. I was asked to write a 5 page article with pictures about this process and the record I set for 6BR, but they have not published it. maybe some day.

 

[jsthntn247]

Ok.. just come back from another test.. 100 Yard OCW for seating depth..

Lapua brass, neck turned to .247 OD

Load: 26.5 grs 2000MR, the reason that i chose this is, that this load was a working load with the Winchester brass i had.. but the primer pockets were too large in that brass.. it was leaking with even moderate loads.. sent it all back to Winchester.

Seating started at Base To Ogive of 2.0335 and finished at 2.0635 (ten in).. best group was with 2.0485 (5K off.) So i will be trying this load at a greater distance sometime soon!~

i don't have a chrony, but the 26.5 gr load was tested with a M.S. V3 with the Winchester brass.. Ave was 2811 with a SD of 7

How'd it do?

 

[USMCDOC]

How'd it do?

It just wasn't working in the long run.. as long as the temps were down.. it was good.. but as soon as you were out in the sun all day.. well that changed everything!

 

[XTR]

If this is for an F class rifle I'd look into getting H4895, VV140, or Varget to do your load work. Rx15 and 2000MR will give you great velocity and will print some awesome groups in testing, but in a match where you shoot long strings and your gear is outside all day the temp sensitivity of both will hurt your scores in the end. The corner 9s that should have been 10s if it held vertical will drive you mad.

In general double based powders seem to have demonstrated that they can't achieve the level of precision required for F class shooting over the range of conditions typically seen in a summertime match environment in the US. Laurie has noted that in Britain where the temps are more moderate some shooters have had success with the higher energy powders.

I went down the 2000MR road a few yrs ago. I still use it for hunting loads, but not for competition loading.

 

[Lone Hunter]

Could you please tell us what load you ended up using out of 7-10?
Forgive my ignorance, why the uneven numbers. I would assume that is powder weight however it could be OAL?
What was your procedure after the ladder?
thanks Link

Link, I think what you are referring to is his muzzle velocity. I could be wrong but that what I think. He has shot #'s and M.V. written down

 

[Link]

Link, I think what you are referring to is his muzzle velocity. I could be wrong but that what I think. He has shot #'s and M.V. written down

Yes I see that now. However I can't see the powder charges off to the right on my screen. That confused me. lol

thanks Link

 

[Lone Hunter]

Yes I see that now. However I can't see the powder charges off to the right on my screen. That confused me. lol

thanks Link

I think that is another ladder test with more velocities written down. Not sure but think so.