Home Forums Reloading Big Game Rifles Major runout with 280AI my thoughts?

Hi guys I have a tried 3 280ai comp seaters 2 reddings and a forster reamed out.
So my problem is no matter what die I use to seat the bergers 168gr on Nosler brass I get 005-010" runout. My brass is sized and only has 001-002" runout max, it is annealed every 2nd firing. Its sized with Lee collet die and or redding full length die.
Now I do not believe its my presses forster coax and supreme rockchucker,I'm pretty sure dont have donuts causing that amount of runout.
It happens only with my 280AI seater with nosler brass, I use same setups with my 7mm Dakota, and my 7rem mag and the most I get is 003"runout.
So Are the necks of the nosler brass bending somewhat during the seating process? As that seems to be the only thing that makes sense to me .
Anybody ever run into this particular problem??

Thx
Elmer

If you have 2 presses, set them up to FLS in the one you are seating with and seat the bullet in the other press.
I experienced this once before and found an alignment issue with the press. At least this would give you some comparative run out numbers.
John

The 7 mag and Dakota have short necks and annealed brass that may be just a touch on the soft side may not effect or bend the neck.

The 280AI however has a long neck and may be more prone to bending

Can't think of anything else it could be.

Shod

I personally think you are annealing the brass too often. Two firings shouldnt work harden brass enough to split it. Try switching to every four firings and see how that works with a sample batch?

Good luck otherwise.

Are the Berger tips bottoming out in the seating stem?

Easy check, pull the seating stem, insert a bullet and spin it lightly, it should make a ring around the bullet if it's not bottoming out.

I'd check the neck wall thickness and make sure one side isn't a few thousands thicker than the other! Nosler brass is supposed to be pretty good though.

I would agree w/rdw's idea that its real possible the seating stem "could" be a poor match to the bullet. If its seating the bullet by pushing at the very tip there is NO WAY you'll get straight seating. This should be very easy to check...just pull the stem and see how the bullet fits. The seater needs to push at the "cup" or about 3/8" down from the bullet tip.

No its not the stem as I have made sure its not touching the tip.
I am leaning that it is the necks somehow bending upon seating probably from the annealing.

Elmer

I don't know how you're chamfering the case mouths but one thing that can help reduce runout is a VLD reamer. I chamfer the cases first with a standard 45 degree reamer and then one cutting pass with the VLD and couple of backward twists to smooth it out.

This prevents the bullet from being cut or dragging on the case mouth ... on one side ... which can induce runout.

Are you using a VLD seater stem?

Boy...with the light seating effort the lee collect die usually leaves you'd have to have (I think) some awful soft shoulders to move during seating?
You've sure got me baffled. One last shot in the dark...any chance the seating die is crimping at the last bit of the seating stroke? Make sure the crimp feature is above the case mouth at the end of the stroke?

OK, so which die is causing the runout?

If after sizing you only have .001-.002" runout with the Lee collet die, I would still say it's the seating stem.

If it's getting worse after sizing with the full length die, it's probably uneven neck wall thickness as mentioned earlier.

Not sure the comp seaters have a crimp feature but i will check.
thx
elmer

All of the major runout happens
when seating, iregardless of which seater i've tried, 3 of them to date all with same results.
Thx
elmer

Wonder if the seating dies are set too far down in the press? Try running a good, straight, ready to seat the bullet case all the way into the seating dies as currently set up, without a bullet and then check the runout. Maybe the seating dies are bumping the necks or the shoulder of the case.

Also, could possibly be too much neck tension? You didn't mention if you are using a bushing die with, or without an expander ball. A few pin gauges would tell you what the neck tension. If too much, more than about 0.005" or so coupled with soft annealed necks and inconsistent neck thickness could cause this problem. If you're using an expander ball in your FLR die then neck tension is most likely not the problem.

Elmerdeer, you might try lubing a bullet before seating and see if it solves the issue.

Shod

Thx guys for all the great advise, I have alot of bullets to load and procedures to try
so I can figure out this little nuisance thats driving me batty lol. But with all the damn runout and me correcting it by bending the bullet in the right direction the gun still shoots pretty well.
But I'm definitely stumped by this one.
Thx
Elmer

How do they shoot?

Elmer...curious how you straighten them. I have a true tool where you insert the case neck and "lift" the casing to correct. Freshly annealed corrects real ez. Was thinking you might have been able to "feel" quite a diff between these cases and others if soft?

Have you tried seating and checking runout in cases that were not annealed?