Sizing new Starline brass

[Kenk]

Morning,
I have always run my new brass through the RCBS sizing die prior to priming, belling, and so on. Is this necessary on new brass, or am I just wasting my time?
Thanks

Ken

[CurtisM]

I have never used brand new brass, will it fit inside your case gauge?

[sep]

I only do it with bottleneck rifle cases to remove any dents in the case necks and to ensure the case mouth is round to accept the bullet. I don't do it for straight walled pistol cases unless there is a visible problem.   

[tommac919]

My new Starline fits into the go-nogo gauge, so no sizing is needed....

The belling of the brass is as you don't want the case to scrap off plating/coating as it enters the case... can also cause wrinkled brass if to tight as it can bind... less bell is better if no issues ( use the least that works )

[The_Shadow]

New Starline 10mm brass doesn't have to be run through the sizer die as its not going to really do much.  They usually are sized at 0.4215" - 0.4220" at the start of the extractor groove where as most sizing dies leave this area untouched and only size to about 0.4225" - 0.4230" anyway.
The expander die will straighten the case necks, but if you happen to find loose fitting bullets you may want to run your brass through regular sizing dies.

I see 0.4230" when I do pass through sizing with my Lee FCD's carbide ring with used brass.

[Kenk]

Great, Thanks!

[gjarcher]

While it is not necessary to size Starline new casings, I do so as to ensure uniform case dimensions and uniform taper crimp.

[Kenk]

Thanks, last new batch of SL went unsized and was fine, but still feel better doing it, Personal problem I'm convinced

[10mm-Admirer]

I find new Starline brass to be tight after I size and expand it. It feels tight when I seat a bullet.  Makes me wonder if the tight grip the brass has on the bullet increases pressures a little.  Maybe it's just the batch I have. The second loading is different.