Getting Consistent COAL and Seating Depth

[mbeavers1]

If your seat is pushing in the tip vs the og this could happen.
Bullet tips are inconsistent.
That's why they have a vld seating stem.

Remove the seating stem and see if the cup is deep enough to make contact with the og

I am using the VLD seating stem.

 

[mbeavers1]

As mentioned already get a comparator tool and measure from the ogive. you will still get some variation but it’s more accurate than measuring from the bullet tip.

I am using the Hornady Comparator tool to measure CH to Ogive, not bullet tip

Not sure if it's been mentioned or not, but a compressed load can do that as well...or so I'm told.

Not sure if it's the correct answer or not, but with a slightly compressed load, I get the same thing sometimes, even with a forster Co-Ax and redding comp micrometer die and VLD stem. I have found running it through at the same setting a 2nd time fixes it...that or back it off a few thou after each round and just take the time to get it exact.

Seems I must be missing something. If load was compressed, then I could see the bullet being forced back out slightly (longer length than planned). In this case, stroking again would help. In my case, the bigger issue is the finished length gets too short. Operating the ram again in this case would not matter, right?

 

[Vandy321]

I am using the VLD seating stem.

Do you feel/hear a slight powder crunch when you seat your bullets? If so, it's the powder/compressed load causing it...no sweat...Just seat it twice and check it...if you need to, start .010 long and slowly work in, as each bullet seats a slightly dif length just do that...

It takes me some extra effort, but I dont settle for anything greater than .001 in COAL. I'm far from experienced in reloading, but after all the damn work that goes into brass prep, I want to do everything I can to make it as consistent as possible..if that means taking 30 seconds run the press 2 or 3 times while seating, that's fine.

 

[mbeavers1]

Do you feel/hear a slight powder crunch when you seat your bullets? If so, dont sweat it, it's not your equipment, its normal. Just seat it twice and check it...if you need need ok start .010 long and slowly work in, as each bullet seats a slightly dif length just do that...

It takes me some extra effort, but I dont settle for anything greater than .001 in COAL. I'm far from experienced in reloading, but after all the damn work that goes into brass prep, I want to do everything I can to make it as consistent as possible..if that means taking 30 seconds run the press 3 times while seating, that's fine.

I dont remember hearing a crunch but will load some and see.

Sounds like you and I are the same, i want it perfect. Just seemed like I shouldnt have to walk it in so much.

 

[GLB]

sorry I didn’t catch that you were already using a comparator. Another technique I use is to seat the bullet lift the arm rotate cartridge 1/4 turn and reseat again and repeat once more. This helps with loads that are compressed. I use the co ax press and Forster dies.

 

[cooperjd]

I had the same problems until i got whidden mic seating dies. the last batch i ran was 20 or 25 rounds, all within .001 of my desired seating depth.

 

[Neverenoughhntn]

Admittedly I didn’t read ALL of the replies, so I apologize if this has been mentioned already.
I’ve had the same issues in the past, and this is what I have since settled on:
Anneal, neck size, THEN run an expander mandrel. Neck tension is much more consistent, resulting in consistent seating depths..... If cleaning brass via sonic or SS, lube the necks with graphite.

 

[bigbulls]

Sounds like neck tension to me, some go in easy and some a little harder, It's amazing how much difference it make when there all the same. I've been where you are and thought I was doing everything right but just a little tweak makes a big change.

 

[WestexSBK]

Someone else might have mentioned this but the linkage in your press playes a roll also. As an engineer you understand the roll stacked tolerances play. Inconsistency in your technique can cause CBTO differences.

Those are some of the reasons I switched to hand dies. I get exacting results every time I seat a bullet. The dies never need adjustment from shelf to press. Love them. But with a quality press and dies you can make equally accurate ammo. Goodluck

Joe S

 

[mbeavers1]

Someone else might have mentioned this but the linkage in your press playes a roll also. As an engineer you understand the roll stacked tolerances play. Inconsistency in your technique can cause CBTO differences.

Those are some of the reasons I switched to hand dies. I get exacting results every time I seat a bullet. The dies never need adjustment from shelf to press. Love them. But with a quality press and dies you can make equally accurate ammo. Goodluck

Joe S

I definitely understand that. I am running a Redding T7 Turret press so I never have to change out the dies, only rotate the head. I have a couple heads set up with different calibers.

 

[muddydogs]

How can neck tension effect seating depth? The case is setting in a steel shell holder placed in the steel press ram, the bullet is being pushed into a steel seating die. Only place for the bullet to go is into the softer brass case and its only going to go as far as the press stroke will allow it plus or minus any press linkage slop. Its not like extreme neck tension is going to stop the press from fully cycling. About the only issue with to much neck tension is the seater plug digging into the bullet ojive during seating effecting how far the system can push the bullet into the case.

Your most likely issue is bullet inconsistency, take your Hornady tool and measure from bullet ojive to bullet base to see just how consistent they are.

 

[doverpack12]

I read the thread through the few days then Rescanned now looking for the bullet and didn’t see mention of which bullet. I’ve had a terrible time with lots of variation up to 0.005” using Berger hybrid 130 otm In my 260. 130 Hornady eldm and 130 Sierra Gamechangers are 0.001” variation at most. I use Forster benchrest seater die with a Redding type s FL bushing sizer. Talked this over with both Forster and Berger last winter. I’m still convinced it’s the Berger bullets but Berger won’t admit to it and they say I can’t measure with ordinary tools because of the hybrid design. Hornady and Sierra had zero wiggle In the seater stem Berger wobbled side to side terribly like the bullet was oblong. Forster had me send In the die with 2 bullets of each of the 3 brands. They gave me a new stem that fits the Hornady and Sierra worse and maybe the Berger a little better. My answer was to sell the remaining box of Berger bullets. If Berger tells me I can’t measure reliably and repeatedly without a laser then my die sure can’t seat the bullet consistent and they need to change their design. They really wanted nothing to do with entertaining the idea the bullets could be out of spec. I have a thread on here somewhere from last winter going through the process I describe above.

 

[Archery Bank]

Also check to see if you have the dreaded doughnut forming on the inside base of the case neck.

 

[shtrbc]

Moly the necks with a brush and powdered Moly. I have done it prior to charging the cases and also after charging but just prior to seating bullet. No difference that I could see. Easier seating force along with much more consistant pressures. This is a benchrest technique thats been around for years.

 

[mbeavers1]

Admittedly I didn’t read ALL of the replies, so I apologize if this has been mentioned already.
I’ve had the same issues in the past, and this is what I have since settled on:
Anneal, neck size, THEN run an expander mandrel. Neck tension is much more consistent, resulting in consistent seating depths..... If cleaning brass via sonic or SS, lube the necks with graphite.

I picked up a Sinclair expander mandrel. Just using the expander mandrel after sizing (FL bushing dies) seems to have helped significantly. I loaded up a ladder test with and without using the expander mandrel and there was definitely a difference. Using the mandrel, the bullets seated +/-0.001 almost every time. Without it was as much as 0.005.

I am cleaning with SS media, so I am going to try the lube.

 

[Unknown Munitions]

Hello, when running a seating session, we set the first round according to COAL needed for production rounds. Then measure CBTO on that round and never again measure COAL or adjust the die. We take Quality Control rounds during the run and check CBTO off the first round measurement. You rifle doesn't care about COAL other than any DBM/BDL max length. Your rifle's chamber and lands only care about the bullets ogive and it being consistent from one round to the next. COAL should only ever be used by a hand loader to comply with DBM or BDL restrictions. That being said if you are having inconsistent CBTO measurements, most all points have been made above. Setting up your die properly, we use Redding comp seaters, bottoming out the die with the right amount of repeatable cam over is extremely important. Neck tension is extremely important so your necks hold the bullet properly and in the same way. Neck tension consists of neck length, diameter, concentricity, inner chamfer, brass stiffness, and inconsistencies pushed outwards. For possible compressed loads, use a sonic toothbrush to vibrate the cases evenly prior to seating bullets. Have fun!