Neck turning question. Depth at shoulder

[AKShooter]

Hello

Well for me I'm turning a new page in my reloading. Having a rifle built with a neck turn chamber. Think I've set myself up decent with tooling. Basically using all K&M.

Anyway, did some test passes. My first case I thought I cut into shoulder too much. Adjusted and I was happy with it.

My question, for lack of detailed photos, I will describe it as the finger nail test. The case I thought I cut too deep, you could feel a slight bump or undercut at shoulder. The case I liked (basically sim to photos). When you run your nail over it, it's almost smooth, no "bump"

Just polling the members, how do your cases feel I guess. Basically gained my knowledge from the article here

Thanks in advance for helping a new guy to neck turning

More background. 7mm, neck reamer is .3195. Cut necks to .0145. So .0290 plus .284 puts me at .003 clearence. What's optimal

Thanks

 

[AKShooter]

For sure check chambering once I get rifle and before loading anything. Just getting familiar turning necks. Thought I'd add that too

 

[bozo699]

I am not following your math,...003 per side would be about right for clearance on a loaded round, I like to turn well into the shoulder, I don't measure it but I eyeball about a 1/16" and make them all the same, if you have the right profile on your cutter it should be a smooth transition.
Wayne.

 

[alf]

http://bulletin.accurateshooter.com/2012/12/tool-tip-optimize-your-cutter-angle-for-improved-neck-turning/

 

[AlNyhus]

AKshooter: When blending into the shoulder, try to get a smooth transition with as little shoulder material removed as possible. Depending on the shoulder angle and the angle ground on the cutter (if any), that isn't always easy to do. If it still leaves a bit of a ridge, you can chuck the case up in a hand drill and dress the edge with a bit of 320 gr. wet paper to knock the edge down a bit.

As to measuring neck thickness, adding bullet diameter and adding all that up for your loaded round diameter...why go through all that? Since what you're interested in is the actual diameter of the neck with a bullet seated, just set the cutter to the mandrel with a feeler guage that's .001 larger than what you estimate the neck thickness to be when you're done, cut a neck, seat a bullet and measure the loaded round. Then adjust the cutter and repeat until the loaded round measure exactly what you want. You'll sacrifce a couple of cases this way, but that's no biggie.

Couple of other things to watch if you're new to neck turning:
-after the necks are cut on your 'setup' cases, make sure and deburr the mouth, then twist the necks in a wad of 0000 steel wool to take off any small ridges and smooth out the chamfer at the end of the neck.
-deburr the inside of the neck mouth, then run a bronze brush inside to remove any high spots
-make sure you measure the neck diameter over the base of the bullet rather than the shank.
-get a plastic bowl and fill it with common rubbing alchohol. After cutting a neck, drop the turner into the bowl as you clean up the necks. This keeps the cutter cool and the necks consistent. Use an old tooth brush to brush away the brass shavings into the alchohol between cuts.
-a 50/50 mix of Mobil 1 5w30 and STP is the best neck lube I've found.
-after you're done, drop the cases into a bowl of acetone and scrub the insides with a nylon .45 cal brush to remove the oil and chips, then rinse again in fresh acetone.

Just my method...hope this helps. -Al

 

[DOGCAPPER]

The K&M cutter is beveled to make a cut on the shoulder...This cut gives the brass flow a place to go rather thaan form a donut inside the case mouth ...Dont worry about feeling a ridge at the piont where the cut stops...A couple of shots will iron it flat.LT

 

[AKShooter]

Thanks guys. Appreciate the additional tips. I'll try to get a decent pic taken

 

[BoydAllen]

If you section a case, I think that you will find that the thickness of the shoulder is such that a slight cut into it will not make a functional difference (unless you are turning before fire forming to a sharper shoulder angle), and as the previous poster mentioned, the small step will be ironed out. One way to approach this is to use a trimmer, such as the Possum Hollow, that indexes off of the case shoulder, to uniform the case mouth to shoulder dimension before turning, and then set your mandrel to act as a limit stop for how far down the neck you can turn.