• This Forum is for adults 18 years of age or over. By continuing to use this Forum you are confirming that you are 18 or older. No content shall be viewed by any person under 18 in California.

Whats .001 of seating depth worth?

Alex Wheeler

Site $$ Sponsor
I like to post targets that are very good examples. And this one is a great example of seating depth at 1k at Deep Creek that Tom Mousel shot tuning before the match. We know +6 shoots and +4 blows up, have not seen +5 yet. Most likely the window is +6-+8 which is very normal for a Vapor Trail in this reamer. Just a good example of why keeping seating depth consistent is so important. thumbnail (46).png
 
What it validates is that seating is not tuning, but it is big to results. In fact seating can be way way bigger than this.

1thou seating change does not affect tune. If it even changed MV by a couple FPS, you could do the same with a single kernel of powder -and that would never cause what you see here.
 
What it validates is that seating is not tuning, but it is big to results. In fact seating can be way way bigger than this.

1thou seating change does not affect tune. If it even changed MV by a couple FPS, you could do the same with a single kernel of powder -and that would never cause what you see here.
I think the proof is in the pudding
Wayne
 
Pretty darn cool see to this after looking at the score sheets from the weekends matches. When you look at (and ponder) the effort that goes into all the testing that leads to top shooters duking it out in a darn close race, it’s just fantastic!

You folks are blessed with not only good people, but talented, dedicated, competitors as well.
CW
 
Last edited:
What it validates is that seating is not tuning, but it is big to results. In fact seating can be way way bigger than this.

1thou seating change does not affect tune. If it even changed MV by a couple FPS, you could do the same with a single kernel of powder -and that would never cause what you see here.
I sort of see what you are getting at with respect to the idea that a small seating change isn't a significant change in MV, and tie that to your definition of tuning, but ....

When most of us use the word tuning, it includes all harmonics and variables that affect group size rather than just the ones that affect muzzle velocity.

For example, a muzzle tuner or barrel weight movement is very small and doesn't add or subtract velocity but we would agree the effect is tuning would we not?

Not to argue semantics, but just to give a different perspective on the tuning of the other harmonics that have a strong effect on the group yet not on velocity.

In any case, and to get back on track..., congrats to the shooter for the LG Group win today and thanks for sharing the target photo Alex.
 
It's not semantics. Seating, like primer selection/striking and brass preps, are prerequisite to tuning.
As far as my defining of tuning: there is powder tune, barrel tune, and system tune. These are independent and separate of one another.

I think the sharpness of a typical seating window (as shown) demonstrates that you're either in the window or dead out of it. So then, would you want to run powder development at pictured +9 seating?
I wouldn't, as it would be a lot harder to find a best load with that.

It's where I'm going with this
 
Is your headspace consistent across all cases at .0005? Brass is alive and has a mind of its own. If you aren't annealing I doubt that you should think about it.
 
Something that has bothered me for a while is how we (me?) measure bullets.

You can take 20 bullets and measure them with a comparator of your choice (I have hornady and short action customs tools) and record your bullets base to ojive. Great.

I wondered if our seating stems contacted the same spot on the bullet and if there would be variances if there was a different contact point.

So I made my own comparator using the seating stem from my wilson seater - this way I'm measuring using the same point of reference

Across my sample of 20 berger bullets there was 0-3 thou variance in contact surfaces.
 
A seating stem datum is not a land contact datum.
And there are variances between these datums from bullet to bullet.
But CBTO is a local measure that local testing rings out, so all that matters is that every round is measured at tested best CBTO.
 
Something that has bothered me for a while is how we (me?) measure bullets.

You can take 20 bullets and measure them with a comparator of your choice (I have hornady and short action customs tools) and record your bullets base to ojive. Great.

I wondered if our seating stems contacted the same spot on the bullet and if there would be variances if there was a different contact point.

So I made my own comparator using the seating stem from my wilson seater - this way I'm measuring using the same point of reference

Across my sample of 20 berger bullets there was 0-3 thou variance in contact surfaces.
These guys aren't shooting Berger's.
 

Upgrades & Donations

This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.


Click Upgrade Membership Button ABOVE to get Gold or Silver Status.

You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.


To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.

Forum statistics

Threads
165,995
Messages
2,207,508
Members
79,255
Latest member
Mark74
Back
Top