First ladder test

[dinosdeuce]

Yesterday was unusually warm weather for November here in Colorado (72F) and I want to go to the 175SMK for my .308 and try Varget as well. Normally I load up 4 rounds each in .5gr increments and shoot at 200yds. When I find a load I like I them work on seating length. This time I decide to try the ladder test. So I loaded up 42 to 44.8grs in .2 grain increments and off the range. I bought white poster board and set up on the 400yd line. Very interesting and informative. I will go with 42.7gr based on the results. I want to test again at 600 yds when time permits to see what that will yield.

Comments and suggestions welcome.

Thanks

 

[paul T]

Re: First ladder test

you seem to have a node at 44.4 as 44.2,44.4, and 44.6 all seem to group well.

 

[dinosdeuce]

Re: First ladder test

Paul T,

Yes they grouped well but the bolt started to have some resistance at 44.6. So I decided to go with 42.7.

Thanks

Dino

 

[TresMon]

Re: First ladder test


Bravo!

 

[dinosdeuce]

Re: First ladder test

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TresMon</div><div class="ubbcode-body">
Bravo! </div></div>

TresMon,

Reading your posts above is what made me try. After seeing what you have written, I will always do load developement this way. Thanks for the education!

 

[Fuzzball]

Re: First ladder test

Your loads #4,5,6 do look good. Suspect #12, 13 are simply flukes.

Part of what your .4 grain wide node proves is that a well selected charge is quite tolerant of small charge variations for both accuracy and velocity.

 

[vman]

Re: First ladder test

Looks good. Sounds like your on the right track.


I will be doing a ladder test for the 175smk very soon as well... just waiting on projectiles to turn up.

Whats your base to ogive length for your loaded rounds?

 

[Williamb]

Re: First ladder test

Isn't it a bit to early to detrmine the optimal load. If you have a node at #s 4,5, & 6 wouldn't you then load 5 rounds of each to see how each grouped. If they individually grouped the same you would then pick the one with the highest velocity. If they did not all group the same then you would pick the load which did group the best. Please correct me if I'm wrong.

Thanks,

 

[dinosdeuce]

Re: First ladder test

vman,

For my setup the measurement is 2.200" using the stoney point comparator with the 30cal insert.


Williamb,

You are right. Re-read Tresmon's post and I jumped to a final conclusion way to fast. Just got excited about trying something new and seeing what a ladder test actually shows.

Thanks for the input.

Since I shoot matches year around with temperatures in the 20's to high 90's I want to shoot the same string at different temperatures to get a good baseline. I won't have to wait too long since it is snowing and not suppose to get better any time soon.

 

[TimK]

Re: First ladder test

Hey Dino, good looking results there. I just went through the same process a few weeks ago and got similarly revealing data.

I wouldn't shoot those loads for group yet, I'd run another ladder at 600. I'm guessing any of those loads will group well enough to shoot Hoser's dogs, and personally, I'd be interested in a load with a lot of tolerance for charge weight.

Depending on how you're measuring your powder, you might be able to speed up the process if you had a <span style="text-decoration: underline">+</span> 0.2g spread to play with.

If you need a place to shoot 600+, PM me and I'll hook you up with my secret spot up near Lake George.

Tim

 

[dinosdeuce]

Re: First ladder test

Tim,

Thanks for the offer! I can go to 600 at Ben Lomond. That will be enough for now. I should have talked to you about this. We can chat at this month's match. I still have around 75 168gr BTHP's to burn through.