Bullet Seating Runout

[mtJim]

You implied that you could seat the bullet in with increments, and these measure low in runout. That you only get a step change in runout with a final seating increment. The seating stem is not doing that.
Donut area comes into play -when you size that donut into play.
I imagine one of the bullet bands is in interference with donut brass at your particular seating depth.

The stick & click part is the stem popping off the ogive (release of wedging) due to mismatch angles and high seating force.

This makes a lot of sense to me. I think this explains exactly what I am seeing happen. But wouldn't a donut be noticeable on close inspection? Wouldn't an expander ball push irregularities to the outside of the neck?

Seating force (relative feel on press handle) seems consistent from case to case and definitely less than other cartridges that I load for that aren't freshly annealed.

I did experiment with an empty case and putting a little imperial on the drive bands of the bullet. This nearly eliminated the induced runout from the seating.

 

[mtJim]

is this a compressed powder charge ? if yes , try seating a bullet without powder to see how the runout is .

Not a compressed load

 

[mtJim]

I don't know that you'd be able to see a donut well. A set of pin gauges or cutting a case in half would be the only way I'd be sure I didn't have them. If you seat your bullets way long such that the taper of the boat tail is above the NS junction, are you still getting bad runout?

No runout until the bullet is fully or near fully seated.

 

[Eric_F]

No runout until the bullet is fully or near fully seated.

Then that sure sounds like a donut. Turn the necks, seat farther out if possible, use a shorter bullet, try a bushing die, or get new brass?

 

[RidgeTop]

Is this something that just happened?
Sounds like the bullet is stuck momentarily in the seating die.

If you have a factory loaded round with a similar bullet, pull the bullet and re-seat it in your die set up.
Or, try seating your bullet in a new factory case without making any adjustments.
Good luck - post what you find.

 

[Hard rock]

Is this something that just happened?
Sounds like the bullet is stuck momentarily in the seating die.

If you have a factory loaded round with a similar bullet, pull the bullet and re-seat it in your die set up.
Or, try seating your bullet in a new factory case without making any adjustments.
Good luck - post what you find.

Is this something that just happened?
Sounds like the bullet is stuck momentarily in the seating die.

If you have a factory loaded round with a similar bullet, pull the bullet and re-seat it in your die set up.
Or, try seating your bullet in a new factory case without making any adjustments.
Good luck - post what you find.

Is this something that just happened?
Sounds like the bullet is stuck momentarily in the seating die.

If you have a factory loaded round with a similar bullet, pull the bullet and re-seat it in your die set up.
Or, try seating your bullet in a new factory case without making any adjustments.
Good luck - post what you find.
I would readjust the seat die , it sounds like you have the die set too crimp with its build in crimp and it's causing the run out . I would back the die off where it barely touches the shell holder. I have gone too bushing dies and comp seating dies and that definitely helps.Whether you have a built in crimp on the seat or not make sure your not camming over hard.

 

[waveslayer]

Many presses aren't perfectly straight of the seating dies. I got into the practice of just starting the bullet being seated, twist the whole case .25" seat the bullet deeper, stop repeat until you do 1 whole revolution of the case, seating your bullet. This will eliminate a lot of run out. Try it out and report back.

 

[Philward]

Like @waveslayer says, give the case a couple turns and run it up in seater again to see if the runout goes away.

 

[mtJim]

Is this something that just happened?
Sounds like the bullet is stuck momentarily in the seating die.

If you have a factory loaded round with a similar bullet, pull the bullet and re-seat it in your die set up.
Or, try seating your bullet in a new factory case without making any adjustments.
Good luck - post what you find.

It is a recent development. I did load development and settled on a good load at about 0.4 MOA. I fired and reloaded the same cases 3-4 times through this process with no issues. I annealed and then did the exact same case prep as before, except now I have this thing with the seating.

I don't have any factory rounds or unfired brass.

Many presses aren't perfectly straight of the seating dies. I got into the practice of just starting the bullet being seated, twist the whole case .25" seat the bullet deeper, stop repeat until you do 1 whole revolution of the case, seating your bullet. This will eliminate a lot of run out. Try it out and report back.

I don't think it's the press. Seating a bullet a little at a time and measuring runout each time it remains minimal. At the end of the stroke on the press handle it jumps from minimal to .008-.010.

 

[Schw15]

I've had this happen and still have some issues with a hornady seater. I believe I read you have a redding seater. Sounds like to me the bullet is getting stuck in seating stem. You can grab a bullet put it in a drill wrap some sand paper or something with grit and run it in the stem. Also i would double check neck tension and make sure you are chambfer the inside of the necks good. Might help

 

[Rflshootr]

It's hard to tell from the pics, but it looks like some irregularity in the shoulder like the seating die is pinching the shoulder. Back the die off 1/16-1/8 of a turn then re-adjust your seating depth.

 

[Hard rock]

It's hard to tell from the pics, but it looks like some irregularity in the shoulder like the seating die is pinching the shoulder. Back the die off 1/16-1/8 of a turn then re-adjust your seating depth.

Has the cases been trimmed too length , you could be too long, causing the seater too bottom out on the neck of the case , at the bullet junction.

 

[Hard rock]

Has the cases been trimmed too length , you could be too long, causing the seater too bottom out on the neck of the case , at the bullet junction.

Do like Rflshootr said back off on the seat die , the die has a built in crimp , that you may be using not realizing the pressure your puting on the case neck at the bottom of the stroke causing runout , especially if your a little long

 

[Barrelnut]

Follow Up on#25~#27 above. Hard to tell, but it also looks like the case neck is not quite square. Kinda like it was trimmed at a slight angle.