Neck turning has consistently been what takes my ES from ~25 down to 15 or less. Like others have said, that doesn’t mean your 25 ES loads won’t do just fine (especially at prs). But I enjoy making as perfect ammo as I can. You seem to be in the same boat.
Also, as far as finding your nodes with a chrono, here is what I do as a first step in load development:
Use .3gr increments with chosen bullet you want to use .020 off lands. 3 or 5 shot groups. If your loading process is very stable, 3 is fine. If it isn’t, 5 or 10 shot groups might be necessary.
Shoot them over chrono. Do NOT shoot groups unless you can make yourself absolutely ignore them. We don’t care about group right now.
We are looking for nodes where your ES is within your standard and is consistent across 2 or more charge weights. For example:
31.7 - 26
32.0 - 17
32.3 - 15
32.6 - 12
32.9 - 31
32.0 through 32.6 produced acceptable ES and was very close. This is showing a stable node within acceptable numbers.
Pick the middle. In this case 32.3. If for example it was just 32.3 and 32.6, pick 32.4 or .5.
That is first step. Moving on:
Take your chosen 32.3. Load 3 shot groups starting with .005 off lands. Increase .003 each group until .040 or so.
Now, shoot groups @ 100yds. You’ll find a seating depth node from the groups. Pick the best node (not just the absolute best group) and load on the long side (gives more forgiveness for throat erosion).
Now, final steps:
Using the seating depth you chose, load 5 shot groups in .1 increments to .5 either side of your chosen charge. For this example with 32.3, you will use 31.8 to 32.8 in .1 increments.
Shoot them over chrono. Then use this to narrow down your micro node. The middle of the ES node that shows up is your final charge weight. You can go back and play around with seating a little if you wish, but don’t have to.
I have a tuner, so after all this, I go back and shoot groups with tuner and dial in. Then it’s done. Load, shoot, clean for the life of the barrel. Chase lands if absolutely necessary.
As mentioned previously. I only look at ES. It’s possible to have a low SD and a high ES, but not possible to have a low ES and a high SD. So I just plot ES.
Your powder drop and brass prep control ES. Seating depth controls group size.
I also use a hydro press. But I’m not looking for a pre determined PSI. This is mostly an incorrect way of using the gauge if you go in with a pre determined number.
Based on testing, you decide on neck tension. Let’s say for example it’s .002 neck tension. The best way to check is to have a pin gauge. Say it’s 6mm/.243. Get a .241 pin gauge and make sure it barely passes in the neck.
Now, take say 5 cases and make sure the pin gauge passes properly. Then use whatever method (brush, lube, etc) on the inside of your necks. Now seat a bullet in those 5 and see where the hydro press puts the pressure. It doesn’t matter if it’s 25psi or 55 psi. You should see a very apparent area as you prepped and checked those 5 exactly the same way. Let’s say it’s 40psi.
This is now your standard for this particular batch. If it’s within 5-10psi each side of 40, you’re good.
The problem with using a pre determined PSI is friction. Depending on carbon inside necks and other things, you may have more or less friction. To show this, take a new piece of brass and get it sized with a pin gauge. Take another and do the same thing. Lube one inside the neck and not the other. Seat a bullet and you will see a large spread on your gauge. Not because neck tension was different, but because of the friction.
A hydro press is a QC check, nothing more. It lets you know if your process up to that point was consistent across each loaded round. Use it as such and nothing else.
