To find seating depth I like to run 2 shots ea per each length and shoot them both in a group that generally tells me everything I need to know about seating depth and doesn't use as many components. I used to start at jam and work my way back .010 at a time but recently watched a Cortina video suggesting .006 at a time. I tried it and I it works well. So it starts at jam, .006 off, .012, .018, .024, .030, and so on.
I also like to shoot 2 ladders half grain increments, the node will usually expose itself with 2 better than just 1. I'd love to test a ladder at distance but the only places I have around here involve canyons and too many environmental factors. In all honesty though if your gun doesn't like the combo you are using it will become prevalent in that first ladder so you're not wasting any more powder.
So you shoot a ladder towards max with 2 rounds instead of one at each increment? So you are looking for grouping and not just chrono efficiency- that each increment is getting you 30-50fps?
I thought the ladder was just for burn efficiency, to see where you aren't getting an efficient combustion jump still short of over pressure. That is, to determine your max velocity from efficient combustion. And then, you were supposed to close the group by tuning the harmonics by decreasing the COL form jam down .006-.010 to see what seating depth hit the harmonics of the barrel right.
But when I was in the south, my teachers said "some barrels just like some bullets". That doesn't really fit that system. I know that bullet choice is relative to barrel twist, but it's still a range. Being recoil sensitive, I don't always shoot the highest BC bullet I can. Esp since my deer loads don't shoot past 350yds.
But I have also gotten different results with different powders. Significant differences. But With 5 bullets and 4 powders, load workups seem fairly random.
Somehow there has to be an efficient way to merge picking a bullet and powder, laddering combustion efficiency, and getting harmonics right.
I assume that for bullet weight/contour laddering should be fairly consistent between bullets. So if I'm shooting 165gr bt .308 bullets, combustion should be close at same seating depths. But as someone without unlimited funds, I would like to have a systematic and efficient system to get a great hunting load for each barrel. Any suggestions?
Here's what I'm thinking:
1. Do a combustion ladder for bullets of same weights and shape to find the neighborhood of top good combustion relative to tolerable recoil. Do this with a couple powders.
2. Shoot a few different bullets at 3-4 load levels in that neighborhood. 3-4 shot groups. (I'm not perfect at the bench)
3. Work promising bullets in best loads in 2-3 round seating depths seating back from the max length you were shooting from.
4. choose the longest COL that groups tight, and load it for practice.
5. Harvest animals
