Inconsistent seating depth.

tactical_tech

tactical_tech

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So after finding my ideal charge weight I've decided to try finding the ideal seating depth. This for my 10tr, I'm using lapua brass and 168gr AMAX and BTHP. I've purchased the Hornady OAL gauge and comparator. I used the OAL gauge and found my my max seating depth. My plan was to go in 5 thou increments. This brings us to the issue I will set my hornady seating die to my desired seating depth, and proceed to load 10 rounds at that depth. However I'm getting about a 5 thou spread which kind of negates the whole process of finding the best depth. I am using the comparator to measure after seating, so it's being measured from the OGIVE.

Any advice?
 
chances are the seating stem doesnt come in contact with the ogive and the point of the bullet bottoms out ... iv never used the hornady dies, so i cant offer solutions

EDIT :a quick google showed that the seating plug is removable, perhaps they offer a replacement that is better suited to the long low drag target bullets? i know that redding comp dies, have 2 different seating plugs available , one "standard" and one for VLD type


EDIT 2:

and they do HERE but it seems like its only for their new dimension custom grade dies.. if you have a older standard die, youre probably S.O.L

but Canadian supplier i dont know
 
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That's a good idea, I didn't think of that. I just took the die apart, coloured a couple bullets with a sharpie then pushed them into the seating depth, it is contacting on the ogive not the tip. So I'm not sure if purchasing the separate stem is going to help. They are the new dimension dies so maybe I'll order up that stem. Or do you think if I'm going after very specific seating depths I'd better of getting something like a redding competition seating die?
 
One thing to check is if your primers are seating all the way into the primer pocket. I had some Win brass that I had problems with the primer not seating all the way causing the oal to be off by a few thou
 
r204 said:
One thing to check is if your primers are seating all the way into the primer pocket. I had some Win brass that I had problems with the primer not seating all the way causing the oal to be off by a few thou
Click to expand...

Why would that be? The primer should line up with the decapping hole in the shell holder, so an improperly seated primer, although not a good thing, should have no bearing on OAL as it doesn't effect the position of the case in the shell holder.
 
What type of press are you using? If the neck tension on your brass is low or the brass is old (necks have hardened) slop in the press may be affecting seating depth.
 
Boomer said:
Why would that be? The primer should line up with the decapping hole in the shell holder, so an improperly seated primer, although not a good thing, should have no bearing on OAL as it doesn't effect the position of the case in the shell holder.
Click to expand...

because if the primer is protruding out of the primer pocket the caliper will sit on the primer and not the bottom of the case causing the OAL reading to be wrong. An easy way to check if primers are seated properly is to stand the loaded cartridge on something known to be flat ( like a piece of glass) and if the cartridge wobbles then you know the primer is not seated all the way.
 
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r204 said:
One thing to check is if your primers are seating all the way into the primer pocket. I had some Win brass that I had problems with the primer not seating all the way causing the oal to be off by a few thou
Click to expand...

Primers are all seated slightly below flush, none wobble when they're stood up on a flat surface.
 
Bullets seat so easily that in many cases (not a pun don't even think it) the seating force isn't enough to get the slack out of the system consistently. Watch the shell holder when you seat the bullets to see if the little sliver of daylight between it and the ram closes consistently. Micrometer dies that measure to the thousandths being used with presses with slop measurable in the 10s of thousandths can be an exercise in futility.You may as well push them in with a pillow.

There are some seating dies that don't crimp that can be cranked down until the die hits the shellholder and that will take up the slack. Redding compseaters can be used like that if you are careful, and if my memory is correct you might be able to do the same with some Hornadys.
 
Use that same comparator to sort your bullets by ogive, put them in boxes in 1 thou increments, let us know what kind of variation you find.
 
Measure your bullets actual length for variations, as you can see your dies at the link below had the most uniform seating depth.
Next examine the seater plug closely with a magnifying glass and polish any rough edges at the mouth of the plug.
You also can have brass spring back problems when seating bullets due to case neck thickness variations and seating force.
Now examine the seated bullets for the mark the seater plug left meaning the ring around the bullet, if some of the marks are longer or vary there is the problem.
All reloading die manufactures will let you send the seater plug back with 2 to 3 bullets and will make a custom seater plug conforming to your bullets.
If you send the seater plug back then also order a new seater plug in case the custom plug causes the same problem with different bullets.
And remember the "tip" of the bullet isn't going to contact the rifling, but the same diameter along the bullets length will.


Are Competition Dies Worth the Extra Money?
http://wolfoutdoorgroup.com/Comp%20Dies.html

Complete Precision Case Prep
Preparing Cases for Long-Range Accuracy
http://www.accurateshooter.com/technical-articles/reloading/complete-precision-case-prep/
 
I just measured about 50 bullets using the comparator and found a 4 thou variance with about 75% being in the middle of that 4 thou spread. I also inspected the bullets on loaded rounds, they all have a ring around them from the seating steam, however they ring does vary from being quite pronounced to barely visible.
 
It looks like you have variations in seating "force" from neck thickness variations, improper chamfer ,etc.

Do you have a VLD chamfer tool to increase the chamfer angle?

What is the diameter of the expander and is it polished?

Dry some dry graphite inside the necks and see if the OAL length variations diminish.

As you can see from the link the average seating die has .004 variance and you stated the bullets vary also.

You may/might need to turn the necks and also try a expander mandrel die.

I sometimes use the Sinclair expander mandrel die to do my neck expanding for turning and expanding the neck before bullet seating for more uniform results. In standard dies you have a expander ball and the straight sided mandrel contacts the entire necks inside surface for uniformity.

Outside Case Neck Turning for Factory Rifles
http://www.sinclairintl.com/.aspx/lid=16135/GunTechdetail/Outside-Case-Neck-Turning-for-Factory-Rifles-

Neck-Expander Mandrels for More Uniform Neck Tension
http://bulletin.accurateshooter.com/2013/09/neck-expander-mandrels-for-more-uniform-neck-tension/
 
bigedp51 said:
It looks like you have variations in seating "force" from neck thickness variations, improper chamfer ,etc.

Do you have a VLD chamfer tool to increase the chamfer angle?

What is the diameter of the expander and is it polished?

Dry some dry graphite inside the necks and see if the OAL length variations diminish.

As you can see from the link the average seating die has .004 variance and you stated the bullets vary also.

You may/might need to turn the necks and also try a expander mandrel die.

I sometimes use the Sinclair expander mandrel die to do my neck expanding for turning and expanding the neck before bullet seating for more uniform results. In standard dies you have a expander ball and the straight sided mandrel contacts the entire necks inside surface for uniformity.

Outside Case Neck Turning for Factory Rifles
http://www.sinclairintl.com/.aspx/lid=16135/GunTechdetail/Outside-Case-Neck-Turning-for-Factory-Rifles-

Neck-Expander Mandrels for More Uniform Neck Tension
http://bulletin.accurateshooter.com/2013/09/neck-expander-mandrels-for-more-uniform-neck-tension/
Click to expand...

I do not have a VLD chamfer, I was unaware there was a special chamfer for VLD bullets, I'll try to get one soon.

I just measured the expander, it comes out to 0.302". It is as hornady makes it. It is smooth but I don't know if I'd call it polished.

I think your on to something with the seating force and chamfer issues. Of the last batch I did I do remember some variances in force to seat the bullets. As well I think I may have gotten a little carried away on the chamfer. I just looked at some finished rounds and noticed some small shavings from the bullets jacket.
 
I picked up a VLD chamfer today and tried it out. After using the VLD chamfer, seating bullets was much easier, I also had more consistent seating depths. Now the seating depths are the same or at most a 1 to 2 thou spread, with one being 3 thou. Thanks for your guys help, I'm also going to try to pick up some neck expanders, to see if I can get even more consistency.
 
I load my ammo with lapua brass and nosler bullets. I use an RCBS press and redding match grade seating die (with the micrometer adjuster). I also use the hornady comparator on a digital caliper. While my overall lengths (tip of bullet to base of case) may vary,y measurement from ogives to base of sink is bang on all the time with a +/- of .02. Also make sure if you have a digi caliper your batteries are fresh, that'll bite you.
Now one thing I have noticed is that when you change the settings on some dies they don't settle in properly so you think your bullets are being seated the same as the one that meets your criteria but the next few will be out by a bit and they start becoming more consistent. I see when I load a big batch. Now you have to back out or in accordingly. I found this loading .223 .308 and 300wm. Using hornady RCBS redding and lee dies. Might be of some to your
 
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