Picking up my new 7-08 today and a question-
I have several hundred .243 brass- will it neck up to 7mm with out a problem?
Hoping to run thru sizer and fire form and be good.

will it work?
thanks
chuck

Chuck, it will work, but I would recommend a Sinclair expander mandrel instead of a regular die, you will be a lot happier with the results. The necks turn out a lot more even and you won't ruin any cases. Lube the inside of the neck good.

ywltzucanrknrl wrote:Chuck, it will work, but I would recommend a Sinclair expander mandrel instead of a regular die, you will be a lot happier with the results. The necks turn out a lot more even and you won't ruin any cases. Lube the inside of the neck good.

Thank you!
I got thinking, and 25 years ago, while doing Bench rest I bought a Sinclair neck turning kit. Still have it and it had a .284 mandrel and holder. It did take some work, glad I did not try thru the die its self!
243 to to 7-08, no cost!
Thanks
chuck

Yes, the mandrels do come in handy and they do a lot better job. If you ever find you have to do it with just dies, do it in steps (24 to 25 to 26 to 28 cal) if you can. And annealing the brass before cuts the losses and the cases come out more concentric. Also, if you do it with dies that have a standard expander button, start it, then back out and turn the case 180 or 90 degrees and run it back in a little and repeat---this will help keep the necks uniform.
FWIW, I've started using the tapered expander buttons (carbide if I can get them) in a lot of my dies because they size easier and I don't get near the dings in the case necks from bumping the case neck against the flat bottom of the expander button. If you have a tapered expander button vs the regular expander button in your dies, you will notice that forming brass is a lot easier and if you mic the necks you will notice they have less run out.

I use a RCBS bullet puller with a bullet installed upsidedown and lots of lube.

Use a tappered expander button...I use one to make my 7mm TCU cases from 223 cases in one pass eazy...eazy going up from a 243 should be even eazier.