question on seating depth/ladder test

[Poppadoer]

The manufacturer of the bullets,powder do test and come up with the c.o.a.l.That's why you use their c.o.a.l and try different charges of powder until you get the results you are happy with.It works for me.

 

[DavidleeCole]

I tend to start with charge weights at a fixed COAL, either manufacturers recommended jump or longest length that will feed from the mag, and look for not just the best group but narrowest velocity spread as well. I'll usually do a velocity ladder first where I focus entirely on numbers from the chrono looking for flat spots regardless of group size. I'll then pick the fastest flat spot load up 5 rounds at each charge weight bracketing it and shoot for groups.

That will usually yield something in the 0.5MOA range with single digit SDs in my experience so I call it good at the point. Honestly, unless it is much more than 0.75MOA I still wouldnt mess with it as long as it still had single digit SDs.

Shooting bughole groups is fun for throwing shade on other people at the range or if you are a bench rest shooter, but for practical shooting disciplines and field use if you look at WEZ analysis, group size has a negligible impact on hit probability once you get below 1MOA.

Well said first round hit in the vitals that's important.

 

[BASE424]

I've always ran a ladder test to find good nodes for the powder charge and then started moving the seating depth around to find best load.

I've read that some folks start with seating depth and then find the correct powder charge.

thoughts on which is better and what charge do you use to find seating depth if you start with that?

Both ways will work. Berger manual says use a nominal charge and test seating depth first and then work on your charge. Most people in the forums will find the charge first and then move to seating depth.

 

[25WSM]

Try the saterlee load development test. I always adjust powder first to find the nodes I can get to. I ladder test them at a minimum of 300 yards. This is to find best vertical charge weight. Then to fine tune accuracy I do seating depth at 100 yards. Once seating is the best I will take that load to 300 and try going up a few 10th or down a few 10th to fine tune it. Done. Sorry the pic is upside down. Don't know why it did that. You can see when the seating depth started to really go away on this load. They are 3 shot groups.
Shep

 

[25WSM]

These are 3 shot groups with my 300 wsm. And it doesn't show a big variance in seating depth change. The other post is a 6.5 creed with 147eldms. This is a 210vld from a 300wsm. Both have Fed 210m and h4350.

 

[FamilyH]

I've always ran a ladder test to find good nodes for the powder charge and then started moving the seating depth around to find best load.

I've read that some folks start with seating depth and then find the correct powder charge.

thoughts on which is better and what charge do you use to find seating depth if you start with that?

I have always set the seating depth with the base of the bull it at the bottom of the neck with out letting the bullet protrude into the powder area of the round. I have not had any problems loading this way.

 

[Toolhand]

I run something like the berger seating depth test first. 3 shots starting on the lands and then stepping the seating depth .020" off till I get to .060" off. Unless its a copper mono bullet, then i just go .030/.050/.070
I pick the best of those and then do a ladder. To get a really good ladder you need brass that has been at least once fired anyways. May as well do a seating test than use that brass for the ladder

I do basically the same except I go in different increments off the lands and test to further off. You will find that one seating depth shoots better than the rest but u can find your node first then tune the seating depth. I think it's just personal preference really.

 

[beaver hunter]

i'm a little new to this reloading , been shooting ammo of the shelf with less that acceptable results ,, now trying to load some accurate ammo ,but can not get less than .200 to .250 jump with any bullet i have tried and still have the shell fit in the mag ,, i'm thinking my barrel is out to lunch or ?

 

[dmax1800]

I develop a load a little different. First I find whether my barrel likes slow powder, mid range powder or fast powder with the bullet I would like to use. For this, I use a powder charge about 60% of the way from the minimum charge to the maximum charge. I have found that seating depth does or can make quite a difference in final grouping. Bullets like Nosler, Sierra, Barnes and Hornady aren't near as finicky as Bergers. Barnes I start at 50 thou off the lands. The others I start at 20 off the lands and then work up the pounder charge. With Bergers, I do some groupings at several different seating depths and about 60% more than the minimum powder.

Along with doing a ladder test, I also do a velocity node test. Hopefully the two coincides. I have found that the velocity node is just as important as the ladder node, and sometimes more important. Then I play with seating depth.

In addition to the seating depth, consistent neck tension is also important, especially at 1000 yards or more. And sometimes 1 thou difference in neck tension can also effect group sizes.

I guess the proof is in the pudding. I've got a 300 WM that will shoot .5 MOA at 100 yards with a hunting bullet and a 6MM Creedmoor that right now is shooting .25 MOA at 100, but I'm not done with it yet. Hopefully I can get it into the high 1s.

 

[Slick8]

In the past I've ran a ladder for charge weight at -.010 off the lands then adjust for seating depth.

I'm starting to rethink that theory and will test it on my next custom.

I'm thinking in theory at least that I will run a mid level powder charge and test for seating depth for two reasons. First by doing seating depth first it will give better details on a 3-500 yard ladder through better accuracy. Second, if your seating depth results in a large jump say .050 or greater you may be able to run a little hotter load in your ladder testing. So why not get the jump rel

 

[RYEWSKY25284]

I've always ran a ladder test to find good nodes for the powder charge and then started moving the seating depth around to find best load.

I've read that some folks start with seating depth and then find the correct powder charge.

thoughts on which is better and what charge do you use to find seating depth if you start with that?

My thinking is powder charge first. I have tried both ways and I believe that the pressure curve of any one charge would have an effect on the best seating depth. IMHO

 

[dougduey]

Both ways will work. Berger manual says use a nominal charge and test seating depth first and then work on your charge. Most people in the forums will find the charge first and then move to seating depth.

Like Base424 stated, both will work. They all get you to the same place. I've tried them all, but load develop one way now.
First, I like to seat the bullet to the most concentric depth possible, which should be where the boat tail/base of the bullet junction is at the neck/shoulder junction of the brass case. If that won't fit in my mag box (all my rifles are for hunting), then I'll seat it to max length that fits in my mag.
Next, I load up charges based on published data, shoot them over my magnetto speed chronograph and find where max is. I look at my velocities to see where the velcoities flatten out, and mark those as velocity nodes. Typically there are 2 of these velocity nodes, and sometimes 3. I pick the one that is closest to max but not showing pressure signs. Then I'll drop down about a grain and work up in 0.2-0.3 gr increments and get a really good idea of where the middle of the velocity node is. Once I find the middle, I load up 5 rounds to shoot and see how it groups and another 5 to give me a good velocity representation. If the ES and SD are good, but the group isn't as tight as I want, I will then, play with seating depth. I usually go up and down 0.005" in seating depth to see where the bullet wants to be. Usually, that's as much adjustment that I usually need.
The 6.5 Guys have a great write up and video on their website.

 

[Will83]

Tagging in.

 

[crazyhorse]

I have used the Berger method with consistent success, trusting people who do it for a living and have done it at a high level for quite some time.

My line of reasoning for finding seating first is due to the fact pressure changes as you move the bullet closer/farther from the max length. If you find a good node then have to make a big swing in seating depth to obtain accuracy, is it possible you could ruin the node based on the pressure changing?