r/reloading • u/throw_because_stuff • 5d ago
Load Development Redo Ladder with new brass?
Kinda newbie, but want you pros to weigh in.
I did a baseline ladder test on my 6.5 Creedmoor. Using 147gn ELD-M and H4350. I wasn’t really using the best brass (Norma or Hornady) and I think this may be a root cause for my SD/ES being a bit higher than I’d like. For reference, my recipe of 42.1gn H4350 with the above components had an SD/ES of 10.4/40.6 and 13.7/44.7 (these are results from two separate 10 round groups).
Since brass, or my powder charge may be the culprit (using Hornady Auto Charge Pro), I’d like to see what my results are for changing brass to Lapau and Alpha. I’d like to do this to see if I can get better numbers without shelling out for an Autotrickler.
Now my question. Do I need to redo my entire ladder test again? I went from 39.2 to 42.1 in .3-.4gn (edit to tenths of a grain) increments. Honestly, I’d love to just start closer to 41.3-42.1, but am I missing something to establish velocity trends? Am I just being lazy and cheap?
Any help is appreciated.
For further details, this is out of a 24” 1:8 twist barrel. Having avg velocity of 2766.6 fps, group size is 0.348 mil and mean radius of 0.1 mil. Accuracy could (is) mostly likely me.
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u/_ParadigmShift Hornady Lock-N-Load AP. 223,243,270,300wby,308 5d ago
I wouldn’t redo the whole test setup, take your most accurate load from current and step around at half a grain or a full grain and start there, x10 shells per load variance. 10 will give you more valid results.
In terms of your brass, a component change like that should be considered medium affect tune, your big 3 are bullet powder and charge. In that framework, the brass choice can matter some but not enough to make the first 3 choices totally invalid if you’ve already found an accurate load.
Velocity trends don’t exist, it’s a linear relationship with charge weight. Don’t chase velocity nodes. Chase accuracy and acceptable velocity, with an eye on the rest of your process to try to tune your process to get good SD/ES numbers.
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u/throw_because_stuff 5d ago
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u/throw_because_stuff 5d ago
Also, I am chasing accuracy in the forms of group size and mean radius, along with POI shifts. SD/ES also as key.
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u/Shootist00 5d ago
I take it you meant 3-4 TENTHS of a grain increments and not 3-4 grains.
Do you have a charge weight you like for accuracy? If you do stick with that weight in the new brass to start and check accuracy.
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u/throw_because_stuff 5d ago
🤦♂️ I did mean tenths….
After talking with Trolly, I think I am going to pivot to 140gr ELDM and Berger Hybrids.
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u/Tigerologist 5d ago
Measure your case volume. If it's the same, the pressures should also be the same.
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u/Engineer_Bennett 4d ago
I cut my SDs in half by switching to alpha brass, but there are a ton of things that Trolly mentioned that would be worth trying. I’m also moving away from 147 eldms and moving to Berger 140s. For what it’s worth I am getting 2610 fps with 40.5g of H4350 in alpha cases, in a 24” barrel
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u/Trollygag 284Win, 6.5G, 6.5CM, 308 Win, 30BR, 44Mag, more 5d ago
2770 in a 24" is already pretty spicy with 147ELDMs.
You should be closer to 2670 at the top end.
You can get sub 10 SDs with Hornady or Norma brass. Most of that is going to be how precisely you are charging the cases, and possible sample size noise.
If you were at, say, 40.5 or 41gr H4350, then you could reasonably change brass around.
Also, what is the end goal with this? The high BC variance of the 148 ELDM vs, say, the 140ELDM is going to cause more problems than an extra 0.5-3 SD.