Another Ladder Test? Added OCW

[jsthntn247]

Shot this today at 300 yards. I don't have access to any further so I guess all that's left to do is load 5 of each from 67-71.5 and see which groups best with the lowest E.S. and S.D. at 300. The velocities on the chrono are what really have me scratching my head. The load is a 162 Hornady SST and H-1000 powder. 67-68.5 had very little vertical, I pulled the 68.0 grain shot because the wind blew a piece of paper out of my bag which hit me in the head about the same time I pulled the trigger . 69-71 grains grouped in 1.399" with .608 vertical. I can't make anything out of this.
67.0 2861
67.5 2974
68.0 2945
68.5 3001
69.0 2966
69.5 3049
70.0 2926
70.5 2943
71.0 3004
71.5 3013

 

[thespecialist]

Re: Another Ladder Test?

I'm digging the vertical on the 67gr-68.5gr load range. If it were me, that's where I'd be hunting my load.

 

[jsthntn247]

Re: Another Ladder Test?

Any ideas on why the velocities didn't "ladder up" like they normally would. I tested the chrony with my .223 and it was spot on. I'm thinking about loading 5 from 67-68.5 in .3 grain intervals and see what happens. If I can't find anything there, I will load 69.5 to 71 in .3's next.

 

[ChadTRG42]

Re: Another Ladder Test?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jsthntn247</div><div class="ubbcode-body">... I can't make anything out of this.... </div></div>
This is very common with this method to work up a load. The only thing you know at this point is that 69.5 to 71 charge weights shoot to about the same point of impact. You can't get any solid info on the velocity with 1 round. You can now load up 3-5 test rounds in smaller increments and see what works best in the 69.5 to 71 grain charges. This will give you fps and ES for each test group, and you can make a selection on which load is best. Just watch for pressure signs. When the velocity does not increase with your powder charges, you've reached max.

 

[Rover31]

Re: Another Ladder Test?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChadTRG42</div><div class="ubbcode-body">
This is very common with this method to work up a load. The only thing you know at this point is that 69.5 to 71 charge weights shoot to about the same point of impact. You can't get any solid info on the velocity with 1 round. You can now load up 3-5 test rounds in smaller increments and see what works best in the 69.5 to 71 grain charges. This will give you fps and ES for each test group, and you can make a selection on which load is best. Just watch for pressure signs. When the velocity does not increase with your powder charges, you've reached max. </div></div>

yep, this reply +1
works well for me also
T

 

[TexIndian]

Re: Another Ladder Test?

Sometimes it helps me to make a simple graph of powder charge vs velocity. Sometimes you can see the graph start to level off before it actually flattens out.

The one-shot ladder has always bothered me a bit. You and your chrony both have to be operating absolutely perfect to get good results. And that doesn't even take into account variations in bullets, cases, etc. I'm with ChadTRG42 on moving to 3-shot groups and smaller variation of powder.

 

[jsthntn247]

Re: Another Ladder Test?

I loaded up 67.3 to 68.5 in .3 grain increments and shot in round robin. The groups are below shot at 100 yards. On the ladder test above these showed very little vertical. If I am reading this right, 67.6 is my ocw load. 67.3 and 67.9 both group on the bottom right corner of bull along with the 67.6. The E.S. on this load was 15fps with a sd of 6. It looks to me after 68.0, I get unexplained fliers because I have reached max speed that my 24" barrel can handle with the slow burning h-1000. The 68.2 and 68.5 loads seemed to show this by one throwing a shot high and the other throwing one low. Also, my speed averaged 2938 at 67.9 grains, 2948 at 68.2, and 2945 at 68.5. I know yall have allot more experience at this than me, this is just my observations.

 

[dieseldr99]

Re: Another Ladder Test?

Although the ladder test and the ocw test looked different. I definitely Agree 67.6 Is your ocw. You now should load one at 67.6 and one at 1% above and one 1% below this powder charge and test the 3 rounds at the 300 yards they should stay sub moa. Then you may have some tuning left with c.o.a.l.
Justin

 

[steve123]

Re: Another Ladder Test? Added OCW

I recently had a similar thing happen using H-1000 in a ladder test.Although the difference was I used it in a cartridge(6x47L) which the powder was too slow for.

I had 14 shots into 2.5" at 300Y with 3 grains of powder spread,some of it being wind drift.The reason why the vertical was so small is because the velocities were close.Only 100fps difference between lightest and heaviest.I could only put so much powder in the case and not reaching full pressure yet.After further testing I discovered the SD/ES was poor as well.

I tried H-4831 next and the ladder was normal with the expected rise and stop with the nodes.SD ended up being 5-6 fps on the finished load.

The pattern I've been seeing the last half dozen ladders with load work up is the best accuracy combined with lowest SD happens right before/under max pressure.My theory is it partly has to do load density and ignition but who knows???

You're almost there.I think the groups will tighten up considerably at the 100Y testing once you find the right seating depth.

 

[Prairie Wolf]

Re: Another Ladder Test? Added OCW

7mm WSM?
7mm rem?

I have a pound of H1000, and 162 amax's and am trying to get around to working up a load in 7 wsm.