Bullet Seating Issue

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Prison Mike

Staff Sergeant
Full Member
Minuteman
Feb 4, 2011
430
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Wilmington, NC
#1
I just bought a new Forster Micrometer seating die and am having an issue that is stumping me. I installed the die and loaded up a 1x fired dummy round to find the exact spot to get 2.217 case to ogive. Got it set and went to loading rounds in new unfired brass but the measurements on the live rounds were at 2.254. I adjusted the die on the live round until I was at 2.217 on the live round. Well I put the dummy round back in just to see if it was a fluke and it pushed the dummy round all the way down to 2.19x (can’t remember the exact number). Why would this happen? All my primers are seated and the round chambers nicely. Should I just stick with the 2.217 measurement from the live round? I’m stumped lol

Update: I ran all the brass through a FL bushing die and added dry lube to the necks and all is right with the world now. Went in very smooth with no friction.
 
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#2
What is the condition of the inside of the neck on unfired brass? If you're not using lube and/or the ID is fairly tight....the stem won't "stop" at the same spot on the bullet each time.

The bullet will stop seating and bullet will slide further up into the seating stem. Making for inconsistent seating.
 
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#3
Rio Precision Gunworks said:
What is the condition of the inside of the neck on unfired brass? If you're not using lube and/or the ID is fairly tight....the stem won't "stop" at the same spot on the bullet each time.

The bullet will stop seating and bullet will slide further up into the seating stem. Making for inconsistent seating.
Click to expand...
It’s brand new lapua brass that all measured .290 outside neck diameter so I just jumped right into loading without neck sizing. I am not using lube inside the necks.
 
#4
Rio Precision Gunworks said:
What is the condition of the inside of the neck on unfired brass? If you're not using lube and/or the ID is fairly tight....the stem won't "stop" at the same spot on the bullet each time.

The bullet will stop seating and bullet will slide further up into the seating stem. Making for inconsistent seating.
Click to expand...
I was also getting indentations around the ogive.
 

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#6
hafejd30 said:
Two things come to mind looking at that

To much neck tension and wrong seating stem

Not necessarily both
Click to expand...
So I just tested one out and ran the brand new unfired brass through my sizer, primed it, powdered it, and seated a bullet and it seated at 2.197 without any indentations which is what the 1x fired brass seated at. So do you think the neck tension on the new lapua brass is too tight from the factory?
 
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#8
Prison Mike said:
So I just tested one out and ran the brand new unfired brass through my sizer, primed it, powdered it, and seated a bullet and it seated at 2.197 without any indentations which is what the 1x fired brass seated at. So do you think the neck tension on the new lapua brass is too tight from the factory?
Click to expand...
This is not an unusual issue for Lapua, or any other, virgin brass. First, Lapua brass that is packaged bulk can have issues for the neck being dented and out of round. So, it's always a good idea to run a mandrel through them to true them up or just neck size (like with a Lee Collet Die). I've done the latter to get good consistent seating on my Lapua virgin brass. After making sure the neck's roundness is trued, it also helps if you give them a little chamfer.

It's common to have virgin brass than has only been trimmed and not deburred or chamfered and you can actually feel the burr both on the inside and outside of the case mouth. A burr on the ID of the case mouth can be a major problem.
 
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#9
straightshooter1 said:
This is not an unusual issue for Lapua, or any other, virgin brass. First, Lapua brass that is packaged bulk can have issues for the neck being dented and out of round. So, it's always a good idea to run a mandrel through them to true them up or just neck size (like with a Lee Collet Die). I've done the latter to get good consistent seating on my Lapua virgin brass. After making sure the neck's roundness is trued, it also helps if you give them a little chamfer.

It's common to have virgin brass than has only been trimmed and not deburred or chamfered and you can actually feel the burr both on the inside and outside of the case mouth. A burr on the ID of the case mouth can be a major problem.
Click to expand...
With there being obvious signs of too much next tension do you think these are fine to shoot or should I pull all the bullets?
 
#10
Prison Mike said:
With there being obvious signs of too much next tension do you think these are fine to shoot or should I pull all the bullets?
Click to expand...
Since my goal would be for getting the cases fire formed, I'd just go ahead and fire them . . . just not expecting any kind of consistent results on target.

If you pull the bullets, the damage is done to them and they're not going to do much better using them in a processed case.
 
#15
Prison Mike said:
Is there usually a direct correlation between tight necks and high pressure? Just need to know if it’s safe to shoot.
Click to expand...

Not enough to worry about unless you're on the ragged edge. Bullets seating into the rifling product significantly higher pressure than pretty much any amount of jumped bullet. Regardless of the amount of tension.

But the "issue" is gong to be the either a single or combination of the following:

- Clean virgin brass has significantly more friction
- Seating stem may need polishing
- Inside diameter of brass too tight

And keep in mind, "neck tension" is a combination of many factors and a sliding scale. I.E. if you lube necks you can get a lighter seating force with a smaller ID than larger ID without lubed necks.
 
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