.223 case mouth size?

[pothunter]

Measures .220" which must be undersize surely. I'd expect this to measure about .223" to allow the brass to contract back down to .222". I don't have another one to check and compare but will order a new expander tomorrow anyway.

Cheers
Greg

It does seem a bit undersize, on various dies that I have had the expander has varied between .221 to .223, apart from Lee collet dies which had a .220 mandrel as they are squishing the neck onto a mandrel rather than using an expander to push a neck out that has already been undersized by the die.
Too much neck tension is usually avoided, but..., if the ammunition that you are making gives good accuracy with that degree of tension, I would probably take a little material off the trimmer pilot so that it fits the neck.

Many knock Lee stuff but I have been quite happy with the results from collet neck sizing dies.

[Thegreg]

It does seem a bit undersize, on various dies that I have had the expander has varied between .221 to .223, apart from Lee collet dies which had a .220 mandrel as they are squishing the neck onto a mandrel rather than using an expander to push a neck out that has already been undersized by the die.
Too much neck tension is usually avoided, but..., if the ammunition that you are making gives good accuracy with that degree of tension, I would probably take a little material off the trimmer pilot so that it fits the neck.

Many knock Lee stuff but I have been quite happy with the results from collet neck sizing dies.

Thanks for the reply. The sizes you have quoted sound right to me. I think it'd be way too much neck tension if it were left as it is. I've changed to this die set from one I was borrowing so it's the die set that's the issue, I'm convinced of it. I know it'd be easy to polish the pilot down a bit but I didn't have this problem before and would rather leave things as standard.

I think I'll get a Lee collet die set for what they cost. Once I've fired the fully sized brass I'll neck size using the Lee and see how they do.

Cheers
Greg