Necking down from 6.5 to 6mm

[Iron Worker]

Just got off the phone from Redding . Mentioned I've been sizing 6.5x284 to 6 x284 in one shot by running the case in their Type C series FL sizeing die. They said "I should be sizing it first in their standard seating die and then next step in the FL die I have". So now I'm wondering if I have the Do-nut effect inside the necks of my brass ? Can I see that from just looking in? Our do I need to run a paper clip are some thing to feel for it ? Hope I haven't ruined some expensive Lapua brass ?

[SBruce]

The "donut" is a wierd thing. I am a little confused by that theory myself, so it would be nice to hear some other opinions.

I heard that the donut is created when necking up brass, which would make more sense (to me anyway). Makes sense that the neck shoulder junction wouldn't want to expand fully or as easily as the neck itself does, and therefore would be a smaller ID once the neck up has been done.

I am failing to visualize how necking down would create a smaller ID at the shoulder junction (based on the same logic of that portion not wanting to move as easily).

FWIW, I just neck size partially with a neck die (not the full length of the neck) and seat bullets and fire. They chamber just a little snug, because there is now a "false shoulder" where the neck die stopped sizing down, but it's only snug for that first fireing (unless it's a really warm load).

I'd like to hear other opinions myself.

[Edd]

I neck 280 Remington cases down to 6mm in one step with a full length sizing die. I've never had any issues.

[gr8whyt]

Originally Posted by Iron Worker

They said "I should be sizing it first in their standard seating die and then next step in the FL die I have".

I'm confused. How do you size a case in a seating die? A seating die does not alter case dimensions in any way. I'm also curious because I plan on doing similar from .277 to .257.

-- gr8whyt

[Iron Worker]

Originally Posted by gr8whyt

I'm confused. How do you size a case in a seating die? A seating die does not alter case dimensions in any way. I'm also curious because I plan on doing similar from .277 to .257.

-- gr8whyt

Ok fair question. Were sizing 6.5x284 down to 6x284. 1st step is a 6x284 seating die not a 6.5. So its does partially size the 6.5 down to 6mm then the final step is in the 6x284 FL sizing die. The tech at redding said " I'll have a more uniform neck ,if done that way"

[MontanaRifleman]

I can't say whether or not you have a donut inside, but if you do, you should be able to take care of it with a neck turning reamer.

[CPGfan]

I have sized probably 1000+ cases just the way you described, you are fine doing it just the way you are.