Seating depth and neck tension variables

[Shooterdevil]

Im working up a load to check velocity for 6.5 creedmoor and as I'm seating the bullet I notice that sometimes the bullet glides in smooth and sometimes it feels like there is more resistance.

During brass prep I check the inner neck diameter and they are very consistent, at about .2585". This is achieved with a hornady match grade die bushing of .287.

I try to give a nice slow consistent lever throw so as soon as the lever bottoms out I stop pushing. When the bullet goes in smooth, my bullet seating depth is a nice .0015-.0020 off lands. When the bullet seating shows resistance it would end up a good .080 INTO the lands. To fix this I have to push on the lever bit by bit (put some weight on it) and measure until I get it into the .002 range. Afterwards they all measure about the same on the outter neck, .292".

Given the necks are more uniform than not, what can cause this resistance when seating the bullet? Seating at an angle? Could this difference in tension effect velocity? I try to isolate variables when reloading but this one is new.

Edit: I experimented and put a spray of lube on a q-tip and swept the inner neck. This seems to make a world of difference. I'm starting to think that the original spray i did for the resize, some of it got inside the necks and some didn't. Leading to some rounds gliding in and others by comparison, offering more resistance.

 

[6Creed73]

Im working up a load to check velocity for 6.5 creedmoor and as I'm seating the bullet I notice that sometimes the bullet glides in smooth and sometimes it feels like there is more resistance.

During brass prep I check the inner neck diameter and they are very consistent, at about .2585". This is achieved with a hornady match grade die bushing of .287.

I try to give a nice slow consistent lever throw so as soon as the lever bottoms out I stop pushing. When the bullet goes in smooth, my bullet seating depth is a nice .0015-.0020 off lands. When the bullet seating shows resistance it would end up a good .080 INTO the lands. To fix this I have to push on the lever bit by bit (put some weight on it) and measure until I get it into the .002 range. Afterwards they all measure about the same on the outter neck, .292".

Given the necks are more uniform than not, what can cause this resistance when seating the bullet? Seating at an angle? Could this difference in tension effect velocity? I try to isolate variables when reloading but this one is new.

I'll never stop telling people to use an expander mandrel as a last step just prior to seating. It will uniform the neck and push small inconsistencies to the outside. This is especially important if one sizes brass then let's it sit for a little while before seating. If it sits, the neck can change/spring back and cause neck tension variations.

I'm not saying this applies you your situation, but since going to a mandrel as a last step before seating, all of my seating variations went away. With match bullets I usually get only .0005 variation in seating depth.

Another thing I do is apply neo lube #2 or graphite powder just before using the mandrel. This also helps the bullet seat smoothly.

 

[fkimble@charter.net]

Is all the brass fired the same number of times or neck annealed the same number of times? Have the necks been trned the same thickness?

Frank

 

[grantre72]

That's a pretty wide swing.

• Compressed loads?
• Annealed brass?
• Inside neck lube? (FWIW, I don't clean inside of necks. Residual carbon, for me, seems to provide more consistent seating depths...)
• Deburring/chamfering?

 

[Shooterdevil]

Is all the brass fired the same number of times or neck annealed the same number of times? Have the necks been trned the same thickness?

Frank

This is brand new lapua brass. I measured 10 casings to get an average and they all showed almost exactly .2585" inner diameter after sizing.

 

[Shooterdevil]

That's a pretty wide swing.

• Compressed loads?
• Annealed brass?
• Inside neck lube? (FWIW, I don't clean inside of necks. Residual carbon, for me, seems to provide more consistent seating depths...)
• Deburring/chamfering?

I dont believe compressed load is the culprit as i feel the resistance consistantly throughout the stroke, not near the end. Plus some rounds so glide in very smooth throughout the stroke.
Not annealed brass. Brand new lapua.
No inside neck lube
No deburring/chamfering

 

[CharlieNC]

So this is new, untouched brass? Need to at least size the necks and chamfer.

 

[Shooterdevil]

So this is new, untouched brass? Need to at least size the necks and chamfer.

They are brand new, but the neck is sized wish a bushing. I tried chamfering some just now to test it out and it didn't make a difference.

 

[Ranger188]

Don't worry about it till you have 1 firing.
Then do your usual brass prep.

 

[saxeTshooter]

I tumbled my new Lapura brass in rice before seating. Helped substantially

 

[L.Sherm]

I never do load development on new brass, with new brass i lube the necks with Redding graphite just for the reason you are describing. After they been shot I rely on the carbon for lube just brush and seat.
I may try and get an idea of powder or primers but nothing serious.

 

[memilanuk]

I tumbled my new Lapua brass in rice before seating. Helped substantially

^ this

I used to hate working with virgin Lapua brass due to the general 'stickiness' of the necks when seating bullets. Tried a lot of things, even just putting a squiggle (technical term) of sizing die wax around the case mouth to ease the entry of the boat tail. FWIW, absolutely chamfer the mouth. Doesn't take much, don't over do it, but definitely *do* break the edge.

Anywho, at one point I was at a large tournament and bumped into the Lapua rep, and asked what he suggested. "Tumble in some used/dirty media" was the response. Basically there is a residue left from their polishing/washing process that leaves everything looking shiny, but is hell on seating. Tumbling will leave a very slight dust film/coating on the neck ID that will act as a dry lube, similar to what others have mentioned above about putting some sort of neck lube (neolube or graphite powder) in there.

 

[NZ_Fclass]

We have all been there at some point.

Check the seating die - ensure that you are not "topping out" ie the case is not too far into the die to interfere with the seating, and that the stem is doing the work.
Anneal the brass
Use a mandrel - I dont use expander balls on most of my dies - certainly not on my competition ammo.
You dont really need lube - well, I don't need lube
Make sure that the powder is not pushing the bullet out.

I'm working toward getting all my dies moving the minimum amount of the brass, either with the use of bushing dies or custom honed dies. There's little point in taking the neck down 10 thou to expand it back 8 thou. Match your dies to your chamber.

 

[KMart]

Anywho, at one point I was at a large tournament and bumped into the Lapua rep, and asked what he suggested. "Tumble in some used/dirty media" was the response. Basically there is a residue left from their polishing/washing process that leaves everything looking shiny, but is hell on seating. Tumbling will leave a very slight dust film/coating on the neck ID that will act as a dry lube, similar to what others have mentioned above about putting some sort of neck lube (neolube or graphite powder) in there.

^^^^
THIS
The last step that Lapua does in manufacturing brass, is to anneal it. Then it is on to packaging. The annealing process leaves oxidation on the inside and outside of the necks.
Tumbling the new cases before doing anything in the way of case prep, will get rid of this oxidation and prevent sticky seating and scratched up necks. The scratched up necks comes from the oxidation building up on the inside of the neck area/bushing in your sizing die

 

[K22]

^ this

I used to hate working with virgin Lapua brass due to the general 'stickiness' of the necks when seating bullets. Tried a lot of things, even just putting a squiggle (technical term) of sizing die wax around the case mouth to ease the entry of the boat tail. FWIW, absolutely chamfer the mouth. Doesn't take much, don't over do it, but definitely *do* break the edge.

Anywho, at one point I was at a large tournament and bumped into the Lapua rep, and asked what he suggested. "Tumble in some used/dirty media" was the response. Basically there is a residue left from their polishing/washing process that leaves everything looking shiny, but is hell on seating. Tumbling will leave a very slight dust film/coating on the neck ID that will act as a dry lube, similar to what others have mentioned above about putting some sort of neck lube (neolube or graphite powder) in there.

I used to use Lyman treated media when I tumbled cases. A residue remained which created all kinds of problems from gumming up my shell holders to forming a "mud" like accumulation in my FL dies. The inside of the necks was also gummed up. So, I had to wipe off the cases with mineral spirits and a shop rag and brush out the necks after tumbling!

When my tumbler finally died early this year, I stopped tumbling. Now I just clean the outside of the necks with 0000 steel wool (which I always did even before tumbling) to remove the carbon and wipe the cases with a shot rag and mineral spirits. I just wished I had started doing it this way 40 years ago. One less piece of equipment, one less consumable (media) I have to stock, much easier to manage my cases, less time to prepare cases for reloading. But the best part is my dies and shell holders are pristine clean. Very happy reloader these days being release for "tumbler bondage".

 

[dgeesaman]

I’ve dealt with this. It’s very frustrating to go through detailed loading prep and get a real hard sticky bullet seating force.

Certainly the lube is a huge factor. I use dry lube and when it’s higher neck tension I swab it around the inside of the neck. I find that works better than just dipping the end of the bullet in the powder. Moly coated bullets are almost too easy.

Plastic bore brushing the inside of the neck kinda seemed stupid to me at first because it’s not removing anything but it just takes one bit of debris stuck inside the neck to hang up. So it helps make sure all loose debris is out of the neck.

Triple check your inner edge chamfer. Slight things there can grab and drag on the bullet.

David

 

[Rset]

Assuming .287 OD after sizing, a loaded round of .292 would give you .005 neck tension. Not excessive, but certainly not considered light.
Given new brass with no lubricant, inconsistencies in wall thickness that are surely present in any factory brass, and the fairly heavy neck tension, seating force issues will be expected.
As for the seating depth, quit easing up on the press and push the bullet to the bottom of the stroke with authority. The bullet won't go any further than the seating die is set for no matter how hard you push it.
While the numbers you posted into the lands (.080) seem incorrect, the variance you are seeing is not going to happen if you bottom out the seating stroke. Lean on the press a little. It won't hurt it.

 

[Zero333]

Clean the brass with dry tumbling media. Not ultrasonic and not wet tumbling.

Chamfer inside the case necks every reload.

if it's still inconsistent then dip the case necks in Lyman's Motor Mica and just wipe outside the case necks prior to or after seating the bullet.

I first resize, making sure I get some sizing spray inside the case necks, then tumble in corn cob and walnut mix, and last step I chamfer inside the case necks. I only change half the tumbling media, and even then I don't do it very often making sure there is always some old tumbling media in the mix.

Never had a problem with seating bullet force inconsistency. I tried ultrasonic cleaning and didn't like it. Not only seating bullets was sticky and inconsistent, it was also a PITA and takes longer than tumbling with media.

If you have a wet tumbler already, you can always use it with dry tumbling media instead buying another tumbler.

This is my brass after tumbling in the corn cob / walnut mix... 75 % corn cob 25 % walnut. What's not to like ?

Once in a blue moon I add a few drops of car polish and run the tumbler without brass and brake up the wet clumps with my hand before dropping in the brass.



Problemo Solved.

Edit: Wet tumbling with the stainless pins is good for brass that's been seating outside in the dirt for a long time and it's beyond dirty.

 

[Zero333]

I don't like bushing dies. All they do is cause donuts. I prefer RCBS dies with their checkered expender ball because it glides out of the case easily. Expender balls that are not checkered like Hornady makes are absolute garbage.