Neck donut

[bench]

Just started to use some of my brass with turned necks and I understand that a donut can start to form inside the neck.
How do I detect it and how do I remove it.


Second question
The expander ball in my forester fl die measures the same as my expander mandrel but the mandrel works to make a slip fit for my neck turning tool(mandrel) while the expander ball in the fl die does not.Is this because the die is not letting the neck expand just that little bit more.

 

[fdshuster]

bench: We had a good discussion going here several months ago, I believe on this reloading thread, about donuts. I check my brass for donuts by taking a fired case as it comes out of the chamber & drop a bullet into the case mouth. With my tight, fitted necks, it may require a little "help", but either way, if the bullet stops with the base at the neck/shoulder junction, a donut has formed there. If it falls all the way into the case, no donut. I tried to cut them out with a carbide tool that is specifically for that purpose, but was unsuccessful. Tried every possible way of doing it, called the tools maker, followed his instructions to the letter & could not get the donuts out. In my notes for loading info for each ctg. I have the bullet seating depth that will cause contact with the donut, and if that measurement is longer/ in front of the donut, I don't worry about it. On a few, especially when using the long, heavyweight bullets if I see that there will be contact, I use a jewelers needle file with a slightly rounded surface that conforms closely with the dia. of the case neck and remove the donut by filing. Takes about 5 seconds per case. For the expander question: I seldom use an expander button in any of my dies. When I need to expand a case neck for outside neck turning or going to a larger cal., like 6mm to 30 cal., I always use the Sinclair mandrels. I like the way they are solidly mounted, unlike the narrow, skinny threaded expander button that is also very prone to bending.

 

[Nomad47]

I use a rat-tail file to remove the donuts - and check the same way. I thought I was the only one to use a file. Nice to see I'm not so crazy after all.

 

[bench]

Perfect guys,
I like simple,the file sounds good to me.
Thanks

 

[expiper]

If the bullet bearing surface (shank) doesnt go down and touch the donut,,I would ignore it,it is of no concern as long as it doesnt pinch the bullet causing high pressure,,,,,this is why it is important to have the correct ammount of freebore in your chamber that matches the bullets that you are using....Roger

 

[Catfish]

The proper way to get the dounuts out is to an inside neck turner. Do a search for inside neck turners at Midway. The reamer are easy enough to find in 22 cal and 6 mm but others get hard to find. I find that after inside neck turnning acouple of time I need to use a neck bushing .002 smaller. Your neck expander should not expand the necks if you are useing bushing dies.

 

[artbosco]

Just started to use some of my brass with turned necks and I understand that a donut can start to form inside the neck. How do I detect it and how do I remove it.

Second question
The expander ball in my forester fl die measures the same as my expander mandrel but the mandrel works to make a slip fit for my neck turning tool(mandrel) while the expander ball in the fl die does not.Is this because the die is not letting the neck expand just that little bit more.

Here's the best tool for removing donuts, click on the picture for a closeup view: http://www.kmshooting.com/catalog/neck-turner-tools/carbide-cutting-pilot.html

It was made specifically for that task. It's a different form of the turning tool mandrel and does double duty. When using one, slide the case neck on first, so you don't scratch up the inside of the neck. The cutting tips are very sharp. If you try slipping it on while using a portable electric screwdriver, that's already turning, you'll tear up the inside of your case necks.

I recommend you keep using the expander mandrel that matches up with your neck turning tool. By matching I mean manufactured by the same company. That's very important because of their design dimensions which usually provides the perfect amount of clearance. Mismatches can be all over the place.

You never mentioned the cartridge your turning. What is it? Does your F/L die use bushings? If it does, remove the expander ball, because you'll be defeating the purpose of the bushings.