Partial resizing

[twarren]

Please explain why a person would want to partial resize with a full length die.
Would it have a tendency to create donuts.

[Robinhood]

Donuts, Somebody say donuts.

Explain what you mean partial sizing.

If the die is a lot smaller than the chamber it might increase the case head space.

Fire forming brass.

[FW Conch]

I fire form. That gives me the "zero" headspace that I desire. Then I neck size only until that case will no longer chamber. Then I full length size just enough so that the case will chamber, and repeat the process.

I have a 358Win that has a very oversized neck in the chamber. I full length size those cases 3/4 the way down the neck and leave a false shoulder to further center the case. That barrel still shoots MOA or less. I have talked to people who think this is a good idea, even with normal chambers? :-)

[bdz65]

I have the Redding shell holder set that you can customize, in .002" increments how far the case is rammed into the die. I use these shell holders to only bump the shoulder back .001" or .002" from the fire formed length. Is this what you mean by partial resize in full length die?

[m12lrs]

I always set up my full length sizing dies to just bump the shoulders back the minimum required to chamber easily.

With my bolt guns it is 0.001 to 0.0015. With Ar's it is 0.003.

Take a fired case and measure head space. Run your die down to the shell holder then back it off about.a quarter turn and resize a piece of brass. Measure headspace for your required shoulder bump. Adjust die accordingly. Repeat until you get what you are looking for. Then put a lock ring on the die and don't mess with it any more.