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Shaving copper off bullet when seating

W

WinJim1863

Private
Minuteman
Feb 27, 2018
45
1
I have occasionally had a problem of shaving copper off the bullet when I start to seat it. At its worst a fine ring of copper.
A related problem- I feel quite a variance required in pressure to start the bullet base when seating (less common with Norma). What do you all suggest?

Background:
6.5 Creedmoor, ELD-M 140 gr
H-4350, 40.5 gr,
Hornady and Norma cases. Problem mostly with Hornady
Homemade annealing machine, once setup flame and time consistent through the batch run; usually anneal before sizing
FL size- Redding w/ .290 bushing or Forster honed to .290
Neck expand w Sinclair .263 mandrel
Seating with redding die
I am not neck turning (last 72 rounds measured .0005 runout, nothing greater than .001)
On ladder tests with this load, SDs average <8 and ESs <20.

I settled on the bushing and mandrel size as these appeared to be common and thought this would be best for 2 thou neck tension. case neck ID measures .262 before bullet seating. Loaded rounds measure about .292 diameter at the neck. I can try to find a .264 mandrel or slightly flare the mouth (but that then would require three steps to size cases).

On the pressure variance required to start seating I assume that is uneven metallurgy case neck to case neck. I thought moving up to Norma would solve that problem; that has lessened it but not solved. Would Lapua or Nozler (or any other premium brand) solve this problem?

Will appreciate your help and advice, JimB
 
WinJim1863 said:
I have occasionally had a problem of shaving copper off the bullet when I start to seat it. At its worst a fine ring of copper.
A related problem- I feel quite a variance required in pressure to start the bullet base when seating (less common with Norma). What do you all suggest?

Background:
6.5 Creedmoor, ELD-M 140 gr
H-4350, 40.5 gr,
Hornady and Norma cases. Problem mostly with Hornady
Homemade annealing machine, once setup flame and time consistent through the batch run; usually anneal before sizing
FL size- Redding w/ .290 bushing or Forster honed to .290
Neck expand w Sinclair .263 mandrel
Seating with redding die
I am not neck turning (last 72 rounds measured .0005 runout, nothing greater than .001)
On ladder tests with this load, SDs average <8 and ESs <20.

I settled on the bushing and mandrel size as these appeared to be common and thought this would be best for 2 thou neck tension. case neck ID measures .262 before bullet seating. Loaded rounds measure about .292 diameter at the neck. I can try to find a .264 mandrel or slightly flare the mouth (but that then would require three steps to size cases).

On the pressure variance required to start seating I assume that is uneven metallurgy case neck to case neck. I thought moving up to Norma would solve that problem; that has lessened it but not solved. Would Lapua or Nozler (or any other premium brand) solve this problem?

Will appreciate your help and advice, JimB
Click to expand...
Have you trimmed with device that gives a chamfered mouth to the neck?
 
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Diver160651 said:
Have you trimmed with device that gives a chamfered mouth to the neck?
Click to expand...
On the cases I'm discussing, Both Hornady (2X fired) and Norma (1X fired) are new and didn't require trimming. I have trimmed older Hornady cases and yes, chamfered both inside and outside (by hand) and had the same problem, in fact worse.
Recently got the RCBS cutter that chamfers in and out, looking forward to trying that.
 
918v said:
Get a K&M VLD champhrer tool and use Imperial dry neck lube.
Click to expand...
Thanks, I will look up K&M VLD tool (haven't heard of it). Imperial neck lube? On a clean case neck and bullet; this won't contaminate powder?
 
WinJim1863 said:
On the cases I'm discussing, Both Hornady (2X fired) and Norma (1X fired) are new and didn't require trimming. I have trimmed older Hornady cases and yes, chamfered both inside and outside (by hand) and had the same problem, in fact worse.
Recently got the RCBS cutter that chamfers in and out, looking forward to trying that.
Click to expand...
looks like your on the correct tract - chamfer the brass will fix it.. I have a K&M VLD chamfer tool in the FS section
 
While I have a chamfer tool it is an old one from my 45-70 blackpowder days. A VLD tool would probably help a lot. I will get one and the Imperial Dry neck lube. thanks to all
 
I had to chamfer new Lapua Brass after using the sinclair mandrel, otherwise some would mar the bullet.
 
I would try an aggressive chamfer, vld tool first and alone. If you have inconsistencies now, adding lube can only magnify issues.
 
Your process is very good and I agree, a VLD chamfer should fix this.

regarding case mouth exoander, I'm not sure if this is possible with the Sinclair but when I use my K&M madrels I need to make sure I don't roll the case mouth in by hitting the expander die body when the ram is fully up. When I do a chamfer after will usually fix it BUT the case mouth hitting the bottom of the die body could also explain the different seating tensions.
 
I've had this with hornady brass being too soft and mushrooming while trimming, that leads to deburing problems. A nice sharp trimming head is the fix I found. Also the VLD tool sounds like a good starting point.
 
He’s annealing. This forms an abrasive oxide in the neck that causes seating pressure variance. Dry lube will make bullet seating smooth.
 
Nope. Tumbling does not remove that oxide from the inside of the neck. Tumbling deposits corn dust on top of the oxide. This dust mimics dry lube.
 
918v said:
Nope. Tumbling does not remove that oxide from the inside of the neck. Tumbling deposits corn dust on top of the oxide. This dust mimics dry lube.
Click to expand...
Oh, ok, so it is magic pixie media dust that makes it work on my end. It also must fill in the voids, now I know why I can achieve negative runout
-00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001
 
I too dont see how lube would contribute to shaving copper off of the bullets that most likely is a result of a sharp 90° mouth.
The one complaint people have about the giraud trimer is that it makes a very aggressive large chamfer: I like that aspect because it makes removes most of the edge that would be cutting into bullets.

Magnifying the differences between smooth and rough seating? Sure, I can see dipping the necks in lube before seating effecting that. It would lessen the total forces across the board but it could make the difference between the two ends of the spectrum more pronounced.

That said hes using an expanding mandrel, not a turning mandrel, so the seating force should already be relatively low, especially with his boat tail bullet.



Whats your lube regimen for prior to sizing? Ive found that uneven or inadequate can cause the brass to stick more than one another and thus not size quite as consistently. Started using more lube (oneshot) and intentionally spraying it inside of the necks and my issues went away.
 
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