Determining a load

[the big greasy]

Everyone usually very helpful here so here is my questions.

Had a wonderful load for my tikka 223 1-8 twist shooting 75 a maxes with varget. Now they are discontinued. Tried everything under the sun to get the newer 75 eldm to shoot, they just won't. I've ordered some 77 SMK to try.
My rifle and mag allows me to load very long.

What's everyone's thoughts on determining seating depth and load powder amount. What first and how does one go about it. Just trying to save some components, but want the best way no matter what that is.

My components are 77 SMK, varget, rem 7 1\2.

I did have a crony, but it didn't fair too well the other day, so it's out of commission.

Thanks.

 

[FireFlyFishing]

Are you familiar with a ladder test?

I do a ladder test first to determine my powder charge "accuracy node." I typically find two accuracy nodes before I hit pressure issues. I like to use the higher velocity node if I can. You have to start somewhere with a seating depth. I usually start around .020 from the jam distance in the lands for my ladder test. This ensures awesome feeding and I've found it's just a great place to start…for me.

Once I've found my powder charge accuracy node, then it's time to find the seating depth. I highly recommend watching Cortina's vid. I haven't tried this yet, but it is way smarter than the way I've done it in the past…so, I'll recommend this method rather than the way I've muddled with seating depth. Next load I develop for my new .308 will utilize this method.

 

[the big greasy]

Are you familiar with a ladder test?

I do a ladder test first to determine my powder charge "accuracy node." I typically find two accuracy nodes before I hit pressure issues. I like to use the higher velocity node if I can. You have to start somewhere with a seating depth. I usually start around .020 from the jam distance in the lands for my ladder test. This ensures awesome feeding and I've found it's just a great place to start…for me.

Once I've found my powder charge accuracy node, then it's time to find the seating depth. I highly recommend watching Cortina's vid. I haven't tried this yet, but it is way smarter than the way I've done it in the past…so, I'll recommend this method rather than the way I've muddled with seating depth. Next load I develop for my new .308 will utilize this method.

Thanks!, I've done this once with a 308 at 500 yards.I know the longer the better, what distance do you run for a 223?

 

[FireFlyFishing]

Both of my .223/5.56 rifles are black guns and restricted to mag length. Unfortunately, seating depth is a tad limited.

It's up to you. Where you want to start and what direction you want to go with trial and error. You could determine jam distance and keep sinking the bullet deeper in the case…or, you could seat to SAMMI and push the bullet out at whatever specified interval you choose. I really like Cortina's method of 0.003" intervals to find that sweet spot.

 

[outdoorguyBP]

I start with .020 off for my seating depth and run a velocity ladder, 10 rounds in .2gn increments working up to the max load for a given powder/bullet combo. I will usually load 2 of each charge and run them back to back or on different days. Today ran one for my boys 6 Creedmoor, time was tight so just ran a single string of 10. I log the data and look for a flat spot in velocity, it looks like I will load another 5 at 38.8gn and see how the SD / ES look along with the group size. If the numbers look good but the group is more than 3/4" at 100yds I might load 5 at .015 and 5 at .025 and see how those work out. We all have our processes, this one seems to work best for me with any rifle I try in on

 

[Mikecr]

For powder I run what-ifs in QuickLoad software to find highest MV from a cool powder, at SAAMI max pressure, 100-104% load density, muzzle pressure <8Kpsi, for my barrel length, bullet, and case capacity.
Then I print an incremental load workup with that powder. I go with this for ladder testing at 300yds.

Before ladder testing I had fully fire formed my brass to stable (usually 3 firings on it).
While fire forming, I run Berger's recommended full seating testing for optimum coarse seating.
I also did some primer swapping at a SAAMI max load, while watching ES from a chrono.
And I also determine MyMax pressure with measurements at the webline.
Now with optimum coarse seating, and best primer, I run ladder testing.

Some folks run tests for a most forgiving charge (an OCW). That's good if running with a tuner. Otherwise, there is no reason for most forgiving to ALSO provide the best barrel tune (as a ladder shows). It is common that powder tune and barrel tune end up separate and different.
And my baseline neck sizing length is half the neck, but never more than seated bullet bearing. My standard neck interference, as set with a bushing is 1-2thou under cal. My primers are set at 2-4thou crush, depending on brand.

After ladder testing, I go to incremental load testing with what the ladder indicated as a best region. With something chosen there, I go to seating tweaking, within it's window, for tightest group shaping.
Then I go to cold bore load development, which can take months.. This shifts powder charge from precision (grouping), to accuracy.
The result parameters, if good enough, are logged and reproduced for the life of that barrel.

 

[outdoorguyBP]

For powder I run what-ifs in QuickLoad software to find highest MV from a cool powder, at SAAMI max pressure, 100-104% load density, muzzle pressure <8Kpsi, for my barrel length, bullet, and case capacity.
Then I print an incremental load workup with that powder. I go with this for ladder testing at 300yds.

Before ladder testing I had fully fire formed my brass to stable (usually 3 firings on it).
While fire forming, I run Berger's recommended full seating testing for optimum coarse seating.
I also did some primer swapping at a SAAMI max load, while watching ES from a chrono.
And I also determine MyMax pressure with measurements at the webline.
Now with optimum coarse seating, and best primer, I run ladder testing.

Some folks run tests for a most forgiving charge (an OCW). That's good if running with a tuner. Otherwise, there is no reason for most forgiving to ALSO provide the best barrel tune (as a ladder shows). It is common that powder tune and barrel tune end up separate and different.
And my baseline neck sizing length is half the neck, but never more than seated bullet bearing. My standard neck interference, as set with a bushing is 1-2thou under cal. My primers are set at 2-4thou crush, depending on brand.

After ladder testing, I go to incremental load testing with what the ladder indicated as a best region. With something chosen there, I go to seating tweaking, within it's window, for tightest group shaping.
Then I go to cold bore load development, which can take months.. This shifts powder charge from precision (grouping), to accuracy.
The result parameters, if good enough, are logged and reproduced for the life of that barrel.

That is an impressive outline, some of it I understand and have experience with, bits I have a vague reference of it to a point that I might be able to BS my way through a conversation (2 beer minimum) and most of it seems to be next level stuff for me. Reminds me of what I my buddies…."when it comes to reloading we all wear a lab coat, it is just some are cleaner than others"

 

[nksmfamjp]

Find a start load. Set OAL to lands minus 0.030", max mag length or bullet bearing surface limit even with base of neck….in that order of priority.

Shoot a 0.5-1.0% increment ladder test until you find pressure. Bolt lift, ejector marks, etc. Back off 1-2%. Load 25. Shoot over chrono into 5 groups. Measure velocity, sd, each group size and a composite group size.

Good enough? Stop.

If not, try OCW type methods to fine tune oal off lands. Like 0.020"-0.1".

 

[Mikecr]

If you don't address half of what I do, just set as much as you can to standard -before changing as little as possible at a time with development.
This, giving you the best view of the change alone, and hopefully mitigate tail chasing.

I do fire forming, primers and coarse seating 1st because they are not tuning, but prerequisites to tuning.
A ladder takes me to barrel tune, which trumps powder tune.
My tune is precision based at 1st, because that get's me fairly close (hopefully) to cold bore accuracy (what I care about).

 

[Tiny Tim]

Like Mikecr, I do seating depth and possibly primers while fire forming cases. Once I have stable, expanded brass, I do my ladder testing (usually at 300 yards).

I generally load two at each powder charge and shoot one of each at separate targets (2 separate ladders). This helps if I miss a reading on the chronograph or pull a shot.

Since I've been doing it this way, I've learned alot about analyzing groups, data, and loading practices. My process is under constant refinement as is my shooting.

 

[FireFlyFishing]

I did have a crony, but it didn't fair too well the other day, so it's out of commission.

Having a chronograph for load development is vital.

 

[Lonewolf74]

@Mikecr; would you expand on how exactly you do your seating depth test, then your ladder afterwards?

Do you shoot groups (similar to OCW) for seating or something different?

Do you find that your ladder test always produce different results then an OCW (barrel vs powder tune)?

I've nearly given up on ladder test because they almost never repeat and seems it's just a snapshot of statistical noise.

 

[Barehandlineman11]

I do 48 rounds
4 seperate charges and 4 seperate seatings
I typically jam .005 then .009/.018/.027 off
Normally ill see a seating it likes at each charge and also will have 12 shots of same charge too see if es sd is workable. Then ill take best groups and load 5 each. I try to do this test at 600+ but it works at 100 too

 

[the big greasy]

Having a chronograph for load development is vital.

I just found out my chrony is working.