Neck turner cutting uneven on shoulder
- Thread starter bsumoba
- Start date
Dusty Stevens
Shiner
Yes. Once you fire em, trim em and re-turn em theyll be perfect
BoydAllen
Gold $$ Contributor
On expanded .220 Russian cases I have done things just about every way possible. With a small amount of expanding up to .22 caliber and then rough turning about .002 over final thickness, I fireformed with a .22 bullet in a 6PPC chamber , and then did another slight expand of the fired cases and turned to final thickness at 6mm.
The point of this long story is that with the cases fire formed to straight condition and only a little expanding being done after, the cuts on the shoulders were very even.
The reason that I experimented with that method was that when I expanded directly to 6mm no matter how carefully concentricity, measured at the case mouth, became two to three times worse. When I turned after straightening by fire forming, and only expanded up slightly after that, my results were virtually perfect as far as cuts on shoulders.
Some time later, I have acquired a PMA carbide expander and die. The particular mandrel that I use has a very long taper, and with the right technique I am able to expand to 6mm without making cases crooked. The key is the shape of the mandrel, its finish, and how I use it. The more force it takes to expand up a case, the more crooked expanding will make it, and that will cause uneven cutting on shoulders. That is why I asked about runout in my first post.
The point of this long story is that with the cases fire formed to straight condition and only a little expanding being done after, the cuts on the shoulders were very even.
The reason that I experimented with that method was that when I expanded directly to 6mm no matter how carefully concentricity, measured at the case mouth, became two to three times worse. When I turned after straightening by fire forming, and only expanded up slightly after that, my results were virtually perfect as far as cuts on shoulders.
Some time later, I have acquired a PMA carbide expander and die. The particular mandrel that I use has a very long taper, and with the right technique I am able to expand to 6mm without making cases crooked. The key is the shape of the mandrel, its finish, and how I use it. The more force it takes to expand up a case, the more crooked expanding will make it, and that will cause uneven cutting on shoulders. That is why I asked about runout in my first post.
nmkid
Gold $$ Contributor
Quote from Boyd Allen:
For my most serious work, I use the tip of a knife blade to scrape off the small ridge that can be formed at the base of the chamfer. This is easy to do for a small set of cases that is typical of short range benchrest. This is something that I came up with on my own. you will not find any written reference on it that I am aware of. I choke up on the blade so that only the tip is beyond my fingers, hold it so that the edge is almost parallel with the inside of the neck, hold the case in my hand and turn it against the edge until feel tells me that the burr is gone. This is the same thing that the long angle K&M tool is designed to deal with.
I use a small round file with the end wrapped in 600 grit paper. I hold the case parallel with the inside of the neck with forefinger pressure on the file and thumb pressure on the case neck/shoulder area. Spin the file with my other hand 2/3 times and it's done. Doesn't take much, it's just brass. Easy does it! This is my own procedure that I have used for years and never had any problems.
For my most serious work, I use the tip of a knife blade to scrape off the small ridge that can be formed at the base of the chamfer. This is easy to do for a small set of cases that is typical of short range benchrest. This is something that I came up with on my own. you will not find any written reference on it that I am aware of. I choke up on the blade so that only the tip is beyond my fingers, hold it so that the edge is almost parallel with the inside of the neck, hold the case in my hand and turn it against the edge until feel tells me that the burr is gone. This is the same thing that the long angle K&M tool is designed to deal with.
I use a small round file with the end wrapped in 600 grit paper. I hold the case parallel with the inside of the neck with forefinger pressure on the file and thumb pressure on the case neck/shoulder area. Spin the file with my other hand 2/3 times and it's done. Doesn't take much, it's just brass. Easy does it! This is my own procedure that I have used for years and never had any problems.
Not to turn this into another merchandising battle, but; the 21st century is not fully free floated. That cutting head wobble is angular from a specific point (not free in hand). This is why your terrible results are so predictable.Elwood said:
Honestly, if I measured 1/2thou variance on necks I just turned, I would take a minute to understand why, rake every contributor into a trash can, and start over.
Everything Boyd said is right. Especially "Let the turner and case float". "Do not fight the wobble."
If you do this, and everything else Boyd said, your results will be fine with brand new unprepped brass.
Someone else said they don't use a stop, but just touch the neck-shoulder junction a bit. I do this as well.
So what of precision in thickness at the neck-shoulder junction? Not needed, just not excess.
This action's only function is to mitigate donuts, and other common sense reloading measures are taken with this as well.
My brass is not trimmed until fully fire formed.
Dusty Stevens said:
I'm lucky. My rifles have "no turn chambers" so I don't have to turn before I've fired them. I merely turn after first firing so the neck thicknesses are even which makes neck sizing a lot more accurate. After first firing and when turning, if i see major "lopsidedness" in cuts, those cases go into the "just for fun" bin. The ones that cut evenly at the shoulder are what I keep for accuracy loads.
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