Inside the case neck polishing/tuning?

[MacLeanHess]

I'm interested in interior neck polishing as a way to get more consistent seating depth.

Check out the dip in the unpolished seating force. I think the case flexes until the seating force exceeds the friction between the bullet and the case, then the bullet, "stutters," into the neck, almost in a stepwise function. Maybe polishing (the second graph in the below video) results in a smoother insertion of the case and less variation.

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Also, I've only been loading for precision rifle for about a year, but isn't neck tension relevant only in the amount of friction it imparts between the bullet and the case neck? I would guess that if you compared the seating force of lubed and lubed bullets, the neck tension would turn out to be far less significant.

 

[209jones]

Strikes me as which came first puzzle, chicken or the egg. Look at the various seating force vs vel/sd/es and effect on target tests to see if there is a pattern over the long term, one way or the other, or not. If the neck is opening as the bullet starts moving, how much of the neck will even affect the bullet, maybe you only need to tend to the last few thou of the neck.

 

[6BRA]

Does coldwelding exist? Ask your kinetic bullet pullers. And then ask why forcepacks are of interest...for seating...and then why does neck tension matter...