Suggested direction in working up a load.

[Bristleback]

When working up a new load, keeping all other things equal, when do you decide to start changing seating depths?

Given many work up loads by first trying a variety of powder charges ~ 40.0, 40.5, 41.0, 41.5,

OR do you fine turn further on your charges, say things are looking pretty good at ~41.0, so you may try 39.9, 41.1, 41.2...........looking for some direction as to WHEN to start adj seating depths.
Many thanks.

 

[Gearheadpyro]

My load development process is as follows,
Step 1. Determine components and maximum load. Determine C.O.L. by either maximum magazine length or chamber. Prepare components, sort bullets (by length to ogive), prepare brass. My load development ammo is the most perfect ammo I make, everything is identical.
Step 2. I start charging at 90% of maximum load, load 5 shots each at 90%, 92%, 94%, 96%, 98%. Load these at factory recommended OAL. Shoot these rounds and look at point of impact and group size. You want to pick a load that the point of impact is close to the same on it and the loads beside it. Also look at group size and use that in determining which load to proceed with.
Step 3. Load .4gr & .2 gr above and below your picked load, shoot and record while looking for same things as in step 2. If two targets in series produced about equal group sizes in step two, I load in .2 grain increments between the two. Pick your best group size out of this step and that is the charge I go with.
Step 4. Load incrementally longer C.O.L.'s out to your maximum length, I usually do 5 shots each in .020" increments. Use the charge determined in step 3. Shoot and record group size. Select the best group size for the next step.
Step 5. Now you are really close to your best load, shoot some of these, try tweaking .1gr of powder or .005" C.O.L. to see if it tightens up any, but your darn close here.

Takes about 100 rounds for me, currently I only sitck with something if it shoots .75" or less at 100 yards regularly. I try to get the loads down to even less than that, but by that time I feel like I'm more of the problem than the ammo.

Hope that helps

 

[jo191145]

Tweak the powder a little first. Lets say your ~41.0 looked good. (I would hope one of the charges on either side looked fairly good too)
I would load the 41.00 again and .2gns on either side. I always want to see if that one good 41.0 group will repeat itself. .2 on either side to see if it can be improved upon.

Everything still looking good you can try seating depths. OR... On occassion I'll jump right to a round robin primer test. Its amazing sometimes how much improvement and variation can be made just switching primers. Of course these days its tough to get a large enough lot of several different primers to make testing worthwhile. It was much easier when the shelves were full.

A primer test right up front can help save time and money. Any tweaking to the load after that will be for that particular primer that works best.

 

[Bristleback]

Many thanks for the input.

 

[cmillard]

i have been trying the ladder type testing and really like it. once i find the "node" then i start playing with seating depths.

 

[jo191145]

Cole

I've been using the Audette ladder since I began handloading for a hobby.
I find it fun.
Every once in a while I'll shoot three shot groups but mostly ladders at 200yds to find the node before shooting groups. lots of ways to skin a cat

 

[jb1000br]

This is what I have been using...

http://www.6mmbr.com/laddertest.html

Builds on all of the ladder type tests, but does some new things.

JB

 

[jo191145]

This is what I have been using...

http://www.6mmbr.com/laddertest.html

Builds on all of the ladder type tests, but does some new things.

JB

Jason??

Good article. I shoot at 200 simply because its my range limit.

I wonder if you'd like to try an expieriment. Next time your shooting a ladder whether it be one shot per charge weight or 3 try this.
Foul and start as normal with low charge. Early in the test jump over the normal progression to the max charge providing your confident its safe.
As expected the bullet should Impact high. Will it? Usually yes. Here comes the funny part.
Now jump back down to the low end where you left off and start laddering back up as normal.

Good chance that round will impact much higher than normal. The next lower yet until your fouling condition returns to the norm for the lower powder charge weights.
Good custom barrels probably have less tendency to do this as they have less personality.
Try it, may make you rethink, not abandon but rethink some theories on round robin testing.

No idea how this test would work at 500yds. At 200yds its usually very interesting.

Another crazy idea I've never tried. An Audette style seating depth test. One consistent charge weight with the seating depths varied... lets say .005 per round.
I've been wondering in my head if that would show a sweet spot .015 wide or so.
I doubt it would work and I quess I like not knowing more than knowing
Would certainly make a mess at 200yds unless a seperate bull was used for every shot.

 

[jb1000br]

200yds is a mess with a good rifle...not enough separation.

RE: your experiment. A good custom rifle will not throw them as you have seen. At 200yds, a 15-shot ladder done as I outline will shoot a big ragged hole with a good rifle. What kind of groups does your rifle normally shoot? There should be no need for rethinking, the round-robin concept removes the re-thinking IMO

I have done OAL ladders the way you mention (charge fixed, OAL varied)...had some spectacular results, especially when deciding whether or not to chase the lands after some throat erosion.

In one test, I actually shot a 1" 3-shot group at 1000yds by seating the bullets 0.002 further out. Crazy, but true. This was actually fired at the 1000yd BR School earlier in the year at Williamsport and witnessed by many. So as you can guess, I made my OAL 0.002 longer

After that adjustment, My wife and I both shot a 4.8" group (Light-gun 10-shot group at 1000) with the rifle (mine was a score Record) and I pulled a 5.5" as well out of the next 7 targets.

Take care,
Jason

 

[jo191145]

Jason

Yes, 3 shot group ladder testing would be a mess at 200yds. Thats why I stick with the original Audette method. Even with my ppc I can see the natural progression of the nodes at 200yds with a target scope. This just shows me the nodes to look at later with group shooting.
And yes when I hit the node they chew a hole. No problem with that, thats what I'm looking for.
Sorry to say even my ppc will not shoot any and all powder charges to the same POI at 200yds. Wish it could, that would make the job much easier

If your ever bored try that test. Heck, shoot four book starting charges for foulers. Fire a group of your normal comp loads then shoot one last starting charge. See where it goes. :-\