Inconsistent Seating Depth

[danny]

Why am I getting inconsistent measurements? I’m trying to seat to 2.175 base to Ogive and it seems to vary between 2.174-2.178. I’m loading Berger 140gr Hybrids and using an RCBS gold medal adjustable seater. I assume this has something to do with the seating stem in the die? Is there anything that can be done about it? Maybe it’s time to upgrade to a Whidden with a stem specific to this bullet.

Are you using a compressed powder charge? I have had that cause such issues, but I am sure others will come up with other causes.

Danny

 

[Jtate]

Inconsistent neck tension is the most.likely cause.
Use a Expander Mandrel to size the inside of the necks all the same.
HB

I have a question about this, I assume the sequence is to use the Expander Mandrel after you use the neck bushing die, is this correct? Does this effect which bushing you select? I have been selecting my bushing size by seating a bullet, measuring across the neck, and subtracting .002. If I am using the Mandrel after sizing do I need to go smaller on the bushing size?

 

[timeout]

Have you sorted bullets by bullet base to ogive? I have no experience with Berger but I would not be surprised if they vary by a thou or few. I find this with other brands, especially Nosler BT and Accubond. Interestingly Swift Scirocco II 180 gr 30 cal have been very consistent demonstrating 1 or 2 thou variance at the most.

My first step in load development is to find a seating depth accuracy node that is 3 to 5 thou wide with a mid-range powder charge. I have found sub-half moa nodes in two different 30 cal rifles with 150 Accubond and 180 Scirocco II.

Try it. You might like it.

IME Berger bullets have very little variance within a given lot#. From one lot# to another lot# Variance is common. Variance in neck tension/seating force is your most likely culprit. Wilson seating dies with an arbor press is a step in the right direction and inside neck mandrels work well for me in some situations.

 

[Mr.quick]

I tried all kinds of different things to get consistent seating depth. Dies, stems, hot glue, etc, etc. It wasn't until I started using a Wilson seater and an arbor press that I got consistent seating depth. I did get VLD stems for my Wilson seaters.

PopCharlie

that is my exact equipment , and i don't have any issues.

 

[David Christian]

I have a question about this, I assume the sequence is to use the Expander Mandrel after you use the neck bushing die, is this correct? Does this effect which bushing you select? I have been selecting my bushing size by seating a bullet, measuring across the neck, and subtracting .002. If I am using the Mandrel after sizing do I need to go smaller on the bushing size?

Correct order of steps. Ignore the .002 general rule of thumb and instead focus on the relationship between how much you are sizing the neck down with the bushing and then how far you are expanding it back out with the mandrel (be sure to compensate for spring back in the brass!).

my goal is to minimize the sizing, yet have it be enough post spring back to allow the mandrel to do its work and leave the neck at my desired size. Trial and error at first.

 

[Jtate]

Ok another question, For a rifle with a magazine (bolt action repeater) what is the minimum neck tension you can use and not worry about the bullets in the loaded cases moving under recoil?

 

[JimSC]

I tested my new Franklin Universal bullet seating die a couple of days ago thinking of this thread. I loaded 50 rounds of .223. Before seating I blackened the bullet with a Sharpie and made sure I was contacting the ogive of the bullet not the meplat. After seating I checked ten random rounds from the box base to ogive and checked the concentricity. Not a full blown test, I just wanted to see if there were any issues. I saw no problems with ten and so I called it good

Seated these on a Lee turret, Lapua cases with various number of firings and never annealed. I used Nosler CC 69 grain bullets. Broke about every "rule" there is and seating depths were as consistent as anyone could want. Not trying to be an ass here but I swear I don't see how such a simple operation can be so overcomplicated

​	BTO​	​	runout​
​	​	​	​
​	1.899​	​	0.0010​
​	1.901​	​	0.0005​
​	1.900​	​	0.0010​
​	1.901​	​	0.0020​
​	1.901​	​	0.0020​
​	1.901​	​	0.0015​
​	1.900​	​	0.0020​
​	1.901​	​	0.0015​
​	1.901​	​	0.0025​
​	1.901​	​	0.001​
average​	1.9006​	​	0.0015​
sd​	0.0007​	​	0.0006​

 

[Joseph Cordeiro]

Why am I getting inconsistent measurements? I’m trying to seat to 2.175 base to Ogive and it seems to vary between 2.174-2.178. I’m loading Berger 140gr Hybrids and using an RCBS gold medal adjustable seater. I assume this has something to do with the seating stem in the die? Is there anything that can be done about it? Maybe it’s time to upgrade to a Whidden with a stem specific to this bullet.

Try mandreling your necks prior to loading powder and seating bullets. Helps with consistent Bullet seating. Inconsistent neck tension will affect Bullet seating inconsistency. Also should sort ur bullets measuring base to ogive.Holland’s Bullet Comparator is a great tool for this.

 

[Mr. Zorg]

I tested my new Franklin Universal bullet seating die a couple of days ago thinking of this thread. I loaded 50 rounds of .223. Before seating I blackened the bullet with a Sharpie and made sure I was contacting the ogive of the bullet not the meplat. After seating I checked ten random rounds from the box base to ogive and checked the concentricity. Not a full blown test, I just wanted to see if there were any issues. I saw no problems with ten and so I called it good

Seated these on a Lee turret, Lapua cases with various number of firings and never annealed. I used Nosler CC 69 grain bullets. Broke about every "rule" there is and seating depths were as consistent as anyone could want. Not trying to be an ass here but I swear I don't see how such a simple operation can be so overcomplicated

​	BTO​	​	runout​
​	​	​	​
​	1.899​	​	0.0010​
​	1.901​	​	0.0005​
​	1.900​	​	0.0010​
​	1.901​	​	0.0020​
​	1.901​	​	0.0020​
​	1.901​	​	0.0015​
​	1.900​	​	0.0020​
​	1.901​	​	0.0015​
​	1.901​	​	0.0025​
​	1.901​	​	0.001​
average​	1.9006​	​	0.0015​
sd​	0.0007​	​	0.0006​

Thanks for the quickie equipment review! I purchased that Frankford Arsenal set as well but I haven't used it yet.

 

[barefooter56]

Why am I getting inconsistent measurements? I’m trying to seat to 2.175 base to Ogive and it seems to vary between 2.174-2.178. I’m loading Berger 140gr Hybrids and using an RCBS gold medal adjustable seater. I assume this has something to do with the seating stem in the die? Is there anything that can be done about it? Maybe it’s time to upgrade to a Whidden with a stem specific to this bullet.

The bullet tips are bottoming out in the bullet seating stem cavity. Call John WHIDDEN and get one of his bullet seating dies. Also , compressed loads can cause this also . Johns stems are thicker around the bullet seating stem cavity opening so they wont crack with compressed loads . However, with a compressed load and light neck tension the CBTO can grow due this an the pressure of the compression of the load.

 

[Joseph Cordeiro]

I have a question about this, I assume the sequence is to use the Expander Mandrel after you use the neck bushing die, is this correct? Does this effect which bushing you select? I have been selecting my bushing size by seating a bullet, measuring across the neck, and subtracting .002. If I am using the Mandrel after sizing do I need to go smaller on the bushing size?

Use same bushing in your sizing die. Use standard expander mandrel for your caliber after sizing. In my opinion the mandrel smooths out the inside of your necks. It also pushes any imperfections inside your necks to the outside leaving a relatively smooth neck which gives you more consistent neck tension.

 

[CarlGeorge]

My seating depth Extreme Spread is .003" or so. It's driving me nuts. I use a mandrel right before charging and seating bullets.

.284 Win; Berger 180gr Hybrids; Lapua necked-up & Norma brass; necks not turned; Redding Competition Seating die with VLD seating stem; not a compressed load; RCBS Rock Chucker press.

Do Redding VLD stems engage the bullet at the tip or ogive? In what I've read about the Wilson stem it sounds like it sits on the ogive.

I'm thisclose to going Arbor/Wilson micrometer seating die.

 

[Joseph Cordeiro]

My seating depth Extreme Spread is .003" or so. It's driving me nuts. I use a mandrel right before charging and seating bullets.

.284 Win; Berger 180gr Hybrids; Lapua necked-up & Norma brass; necks not turned; Redding Competition Seating die with VLD seating stem; not a compressed load; RCBS Rock Chucker press.

Do Redding VLD stems engage the bullet at the tip or ogive? In what I've read about the Wilson stem it sounds like it sits on the ogive.

I'm thisclose to going Arbor/Wilson micrometer seating die.

I shoot a modified.284 Winchester ( Shehane) also. I also use Lapua 6.5-..284 brass. I neck up new brass in a 2-stage process ( mandrel) and fireform. I use .283 mandrel for the first 3 fireings because I have found there is typically more spring back and inconsistent Bullet seating/neck tension. Also found that this clears up the donut at the shoulder and neck which can cause Bullet seating inconsistency also. After the 3rd firing I use a .282 mandrel for the life of the brass. It is important that you mandrel right before load. If you let the brass sit for a few days after sizing/mandreling I have found the necks tend to tighten up again causing bullet seating and neck tension inconsistency.