The chicken or the egg?

[diego-ted]

From all I have gathered after consistency in brass prep there are two major factors that affect accuracy. The first being powder charge the second being seating depth. So which one should initially be addressed in load development. From what I read, I see powder charge developed utilizing the ladder test should be done then seating depth? Secondly, does case length have any effect on either?

Thx Ted

 

[MitchAlsup]

Re: The chicken or the egg?

Pick (somewhat randomly--after cosiderable reading) the seating depth (like 0.015 from the lands). At least one highly qualified reloader (here) recommends starting with the bullet seated at/on/in the lands, because as you back the bullet away from the lands, pressure can only drop.

Then do all the charge weight experiments.

Then come back and do the seating depth experiments.

 

[Gruff]

Re: The chicken or the egg?

To me, seating depth takes a back seat to what I consider the 3 major factors in accuracy. These being charge weight, neck tension, and neck run-out.

 

[Tomekeuro85]

Re: The chicken or the egg?

ive always wondered the same thing.

My solution was to find the lands and seat the bullets touching...

Then I found the best charge weight with bullets touching.

Then I loaded that charge -.01, -.005, +.005, and +.01

.005 jammed produces fairly consistent half moa so I stayed there.


To try it the other way would take a lot more ammo I'd think because you'd be picking an arbitrary powder charge, not necessarily one that is already known to be accurate.

 

[diego-ted]

Re: The chicken or the egg?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tomekeuro85</div><div class="ubbcode-body">ive always wondered the same thing.

My solution was to find the lands and seat the bullets touching...

Then I found the best charge weight with bullets touching.

Then I loaded that charge -.01, -.005, +.005, and +.01

.005 jammed produces fairly consistent half moa so I stayed there.


To try it the other way would take a lot more ammo I'd think because you'd be picking an arbitrary powder charge, not necessarily one that is already known to be accurate. </div></div>

So are you saying once you determined your lands you would start at a mim for any given powder then work you way up? Or at what charge do you start, in the middle?

Ted

 

[Tomekeuro85]

Re: The chicken or the egg?

Once I found the lands, I did the same ladder test 5 times in a row, going low charge to book max charge. Just to be sure that my results were valid and it wasnt a fluke. If you get the same "node" readings 4 out of 5 times you're probably on to one. Doing it once can be a fluke so I don't trust it personally.


Out of those ladder tests, I found the best "node" and then did five, 5 shot groups to verify, still just touching the lands.


Once I found those were in agreement with past results, I did the seating depth variations, and picked the best one of those. After 2 or 3 five shot groups of each seating depth.

I'm big on repeating things a few times to make sure that the results are actually the results and not luck. When I first started i'd do one group of a particular load and judge by that.. but I found that sometimes a "bad" load would shoot a half inch group at 100. Then id load up 50 rounds and I'd never go under 1" the next session. Just like a "good" load might look bad for one group but the next 4 may be screamers.

Some might argue that this is a waste of ammo/barrel life but eh, i think its fun to play around with laods so I don't mind it. I suppose if you have something like a .223WSSM you may want to avoid extensive load development for the sake of useful barrel life.

I'm no pro so YMMV but thats how I did mine and my targets do the talking for me... Typically .5-.7moa out to 300 consistently, with 52gr matckings in a factory 700 .223.

 

[gunsnjeeps]

Re: The chicken or the egg?

Case length can have a minor effect on neck tension. It's more important to all be the same length than to have lengths all over the place.

Tom, those coasters look great I might have to do another order.

 

[BBeyer]

Re: The chicken or the egg?

Tom, if you have a turning center you can use I have a jig you could make that I think is great for chambering barrels. Gunsmiths could be interested, but I dont know how to get a pic. or drawing on here.I have made up a few gagets that I have used myself to make things a lot easier, without the luxary of CNC. I have an entirely manual Clausing lathe and Bridgeport mill.

 

[vman]

Re: The chicken or the egg?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tomekeuro85</div><div class="ubbcode-body">Once I found the lands, I did the same ladder test 5 times in a row, going low charge to book max charge. Just to be sure that my results were valid and it wasnt a fluke. If you get the same "node" readings 4 out of 5 times you're probably on to one. Doing it once can be a fluke so I don't trust it personally.


Out of those ladder tests, I found the best "node" and then did five, 5 shot groups to verify, still just touching the lands.


Once I found those were in agreement with past results, I did the seating depth variations, and picked the best one of those. After 2 or 3 five shot groups of each seating depth.

I'm big on repeating things a few times to make sure that the results are actually the results and not luck. When I first started i'd do one group of a particular load and judge by that.. but I found that sometimes a "bad" load would shoot a half inch group at 100. Then id load up 50 rounds and I'd never go under 1" the next session. Just like a "good" load might look bad for one group but the next 4 may be screamers.

Some might argue that this is a waste of ammo/barrel life but eh, i think its fun to play around with laods so I don't mind it. I suppose if you have something like a .223WSSM you may want to avoid extensive load development for the sake of useful barrel life.

I'm no pro so YMMV but thats how I did mine and my targets do the talking for me... Typically .5-.7moa out to 300 consistently, with 52gr matckings in a factory 700 .223. </div></div>

Sounds like your doing very well these days Tom

 

[Tomekeuro85]

Re: The chicken or the egg?

haha yea i'm doing ok, pretty busy with everything as always

 

[turbo54]

Re: The chicken or the egg?

When trying a new bullet, I always run twoa basic pressure ladders, a couple thou jammed.

Its two 10 round strings and you've established a charge limit as well as found your nodes...

Next, load some groups at your node with various seating depths. You're there.

To tune MORE, run a new pair of ladders at that seating depth. Load higher than your past max charge with bullet jammed.

You can continue repeating this iterative process until you're satisfied with accuracy.

Beware, if you haven't found accuracy after your FIRST seating test, change powder and start over, or give up on that bullet. You're not going to go from shit to gold by FINE tuning. If you do, its a fluke.

With this process, you should have the recipe for great ammo (bullet/rifle/powder willing) in 50 shots.