What to tune first: seating depth or powder charge?

[Yosemite Steve]

My big question for the moment? Is it more efficient to develop ammo for a particular gun and bullet by starting with seating depth or powder charge. I was advised by someone who is very experience to start with a moderate powder charge and find the best group by adjusting seating depth first. This has worked well for me... but I usually shoot about 30 rounds for that process and then another 30 or so to seek the best charge for the given powder.

Last night I was reading about ladder testing first and then seeking the sweet spot in depth. Since one affects the other where do you start?

Another thing I read about was listening to the rifle or feeling it hit that sweet spot where it gets really accurate. One person described it as a "boing" that happens when the harmonics of the barrel meet the acoustics of the detonation. I have experience this! My rifle has indeed made more of a "boing" on certain loads but I never really thought much of it at the time.

Here is link to one method, by Sierra Bullets Product Development Manager Mark Walker: https://sierrabulletsblog.com/2014/0...d-development/

Also this link from 6.5 guys: http://www.65guys.com/10-round-load-...t-ladder-test/

Where do you start?

[ammo.crafter]

I have always began with the most consistant load formula...case, primer, powder charge, bullet, etc.

When consistency finally arrives I would move on to bullet seating.

Just my method over the years.

[Yosemite Steve]

I moved this to the main reloading category. I don't know how this got put in casting....

[tangolima]

Powder charge is stronger function than bullet seating depth when it comes to group size. So I vary powder charge first. By default I have 0.05" bullet jump.

-TL

Sent from my SM-G930T using Tapatalk

[Yosemite Steve]

By default I have 0.05" bullet jump.

I like that idea. The Sierra guy talked of working up his powder on the lands. It would seem that the pressure spike that creates might change the game. There are so many differing views on this that it's hard to know where to begin. But I like your idea of starting with the .05 bullet jump and I think I will try that meathod for my next development. Thanks!

[Yosemite Steve]

At the range today, with my new chronograph... I shot the last three bullets I developed for hunting earlier this year. I was saving them to see if they were as fast as the book suggested they might be. All three shots one holed! This is the first time this has happened for me. https://www.dropbox.com/s/eavdg6m3ec...sized.jpg?dl=0 Be damned if I didn't feel the rifle ring for all three shots. I didn't notice it shooting any other rounds. I'm having my whiskey to celebrate this success! 50.0 grains of IMR 4064 with a 180 SST seated .005 off the lands. 2631,2635 and 2643 fps. Boing! Please note that this load is above the suggested max load in modern manuals and may be dangerous to duplicate.