Seating depth for A-max bullets

[Iron Worker]

In my 7mmWSM 162gr A-max touching the lands is producing poor accuracy. How far off the lands are y'all seating A-Max bullets ?

 

[benchracer]

Do the Berger seating depth test. Since you have already eliminated one of the seating depths (touching the lands), 9 rounds should tell the tale.

 

[FearNoWind]

Eventhough I don't personally endorse this testing procedure, here's the link:
Berger Bullets Seating Method for VLD Bullets - A "Sweet Spot" with a Long Bullet Jump will give the best accuracy.

 

[benchracer]

It's also been made into a sticky at the top of this forum...

 

[Deleted member 46119]

in my 7mmwsm 162gr a-max touching the lands is producing poor accuracy. How far off the lands are y'all seating a-max bullets ?

-0.005

 

[bill123]

Eventhough I don't personally endorse this testing procedure, here's the link:
Berger Bullets Seating Method for VLD Bullets - A "Sweet Spot" with a Long Bullet Jump will give the best accuracy.

Curious, what do you use?

 

[frequent misser]

.005-.010
There is usually a node way off also. I have one shooting them .060 off.

 

[FearNoWind]

Curious, what do you use?

I have never had a problem finding a sweet spot within .030, even with Berger bullets. I start .020 off the lands using three round sets to find a powder charge that groups well. Then I work with three round sets, moving seating depths in .003 increments, to find my seating depth "sweet spot".
I have found that, at least in my rifle, Berger Hybrid Target VLD's don't like to jump. I have sample targets from some of my tests that clearly reveal the improvement in accuracy for this bullet (180 grain in my.284) as it moves closer to the lands.
What I find bothersome with the published Berger test is, geographically speaking, by the time you find the neighborhood where the sweet spot might reside you've already fired 24 rounds and you're only on the block where the address may actually located. With the spread between seating depths viewed as residences, you've still got to look at forty (.040 between sets) to find it.
That requires a lot of ammo.

 

[benchracer]

I don't follow Berger's procedure to the letter. I use a simplified version of the procedure. It has always worked out for me in a manner very similar to what is pictured below. Most of the time, I only shoot three rounds loaded to each .040" increment. After a 12 round seating depth test and an 18 to 24 round powder charge workup, I have a very accurate load. I can do the whole thing in a single trip to the range.

 

[FearNoWind]

I don't follow Berger's procedure to the letter. I use a simplified version of the procedure.

My eyes are old and tired.
Am I reading your COBL range correctly as:
2.340 - 2.350 - 2.450 - 2.470?

 

[benchracer]

My eyes are old and tired.
Am I reading your COBL range correctly as:
2.340 - 2.350 - 2.450 - 2.470?

No. 2.350 - 2.390 - 2.430 - 2.470. Counterclockwise from the lower right corner.

This test represented a slight departure from normal for me because I normally start at the lands and work backward. With long bullets in larger caliber rifles, that is normally pretty simple to do. With the 53 VMAX, COAL to the rifling measured 2.510. I wasn't comfortable seating the bullet that far out, so I started at SAAMI length and worked my way forward.

When I have followed my adaptation of the Berger test, the most accurate seating depth comes in at .040" or .080" from the rifling most of the time.

 

[FearNoWind]

No. 2.350 - 2.390 - 2.430 - 2.470. Counterclockwise from the lower right corner.
...
When I have followed my adaptation of the Berger test, the most accurate seating depth comes in at .040" or .080" from the rifling most of the time.

I must confess that I'm impressed with your results. That 2.430 group wouldn't need a lot of work to fine tune.
Even though my routine works, I'm gonna try your method next range visit and see if the modified version you describe broadens my range of node possibilities.

 

[bill123]

I have never had a problem finding a sweet spot within .030, even with Berger bullets. I start .020 off the lands using three round sets to find a powder charge that groups well. Then I work with three round sets, moving seating depths in .003 increments, to find my seating depth "sweet spot".
I have found that, at least in my rifle, Berger Hybrid Target VLD's don't like to jump. I have sample targets from some of my tests that clearly reveal the improvement in accuracy for this bullet (180 grain in my.284) as it moves closer to the lands.
What I find bothersome with the published Berger test is, geographically speaking, by the time you find the neighborhood where the sweet spot might reside you've already fired 24 rounds and you're only on the block where the address may actually located. With the spread between seating depths viewed as residences, you've still got to look at forty (.040 between sets) to find it.
That requires a lot of ammo.

That's what I do (and probably got the idea from one of your previous posts). How close to the lands do you go?

 

[FearNoWind]

... How close to the lands do you go?

I usually find what I need without touching the lands. However, with Berger Hybrid VLDs, I've found that contact with the lands is often what they like. It depends, of course, on the rifle. I just replaced the barrel on my .284; same reamer for new barrel. The old barrel liked .020 jump. This barrel seems to like them better touching the lands.
I love Berger bullets. I just wish they weren't to darn finicky.