Nect Turnig with the K&M Neck Turner

[Dave Brown]

While turning necks with the K&M neck turner, I noticed that the mandrel with teeth is marring the inside of the case necks. It also looks like it has threaded the insides. Would this not affect accuracy? I am using PM neck turning oil and a black and decker cordless screwdriver to turn the necks.

Thanks

 

[JRS]

Sounds like you need to slow down a bit.

 

[dkhunt14]

With the one with the donut cutter on you need to slide in in and out with it not turning. Matt

 

[Dave Brown]

With the one with the donut cutter on you need to slide in in and out with it not turning. Matt
[/quot

Not exactly following you on this?

 

[LHSmith]

If your bullet base is well away from the neck/shoulder junction, I would not worry about donuts.

 

[jlow]

With the one with the donut cutter on you need to slide in in and out with it not turning. Matt
[/quot

Not exactly following you on this?

I think what he means is to slide the cutter in not turning until you get to the donut area before rotating the cutter. When done turn off the rotation before sliding out. You are really only interested in cutting the donut.

 

[Patch700]

The mandrel you speak of can be a catch 22 at times... if you run your brass up onto the appropriate sized mandrel first then theoretically whatever donut is there would then be ironed out to the exterior..

And if you did not expand the necks then you are playing a game of very close tolerances with regards to having the ID of the necks being a bit tight on the mandrel and this may be causing some of your thread like problems.

I would first expand on the matching K&M mandrel and try turning one case by hand to ensure your drill is not wobbling the case and in effect causing the neck to not run true on the mandrel.

I use some of these mandrels on a few calibers and have not noticed the problem you've mentioned.

Good luck.

 

[Macropod]

It is possible to scratch the inside of the case neck with the donut cutter. I just stop the drill and pull it straight out. That seems to work.

A plain mandrel would be better I believe. Using the expander as previously posted largely negates any benefit anyway.

 

[Chaotik]

While turning necks with the K&M neck turner, I noticed that the mandrel with teeth is marring the inside of the case necks. It also looks like it has threaded the insides.

I have noticed the same issue with my K&M neck turner, and am also looking for a solution. I run all of my necks through the appropriate exander mandrel before attempting to neck turn, and use imperial wax for a lubricant.

 

[Dave Brown]

With the one with the donut cutter on you need to slide in in and out with it not turning. Matt
[/quot

Not exactly following you on this?

I think what he means is to slide the cutter in not turning until you get to the donut area before rotating the cutter. When done turn off the rotation before sliding out. You are really only interested in cutting the donut.

Ok, now that makes sense to me. However, I am trying to turn down the virgin Lapua brass to a .014 consistency. I am then checking it on a Redding case neck gauge and I think the marring inside the neck is flawing the number by roughly .0005. You can feel it hang up when you try and rotate the brass. I have ordered some more mandrels without the teeth from K&M.

 

[Dave Brown]

While turning necks with the K&M neck turner, I noticed that the mandrel with teeth is marring the inside of the case necks. It also looks like it has threaded the insides.

I have noticed the same issue with my K&M neck turner, and am also looking for a solution. I run all of my necks through the appropriate exander mandrel before attempting to neck turn, and use imperial wax for a lubricant.

I just ordered some mandrels without the teeth from K&M and I do it the same way you do. No way I am turning all this brass by hand but I may have to come up with another method other than the cordless screwdriver.

 

[Dave Brown]

If your bullet base is well away from the neck/shoulder junction, I would not worry about donuts.

Would this doughnut not affect your pressures?

 

[stgw77]

If you will use correct freebore/bullet combo, bullet will be seated higher than the doughnout, so doughnout will not affect seating process...nothing to worry about this way...

 

[SS427]

My 6mm and 20 cal K&M turning mandrels have the same donut removal teeth.

You have to be extremely careful while doing the initial turning or those teeth will bite into the inside of the case a little. Typically it only occurs very close to the mouth when you are done turning and happens when the sides of the mouth are not reasonably parallel to the mandrel. If you hold everything perfectly straight it doesn't happen, but angle the case a little when you remove it from the mandrel and it will leave marks.

While fire forming all but the deepest marks go away. At least that is what I have found. Also my on target results tell me it isn't a big enough deal to worry about. Just try and be careful and you will avoid the problem for the most part.