270WSM to 300 WSM

[BIGMAC]

Procedure used to form 270 WSM to 300 WSM pros and con.Thanks in advance for any info.

 

[fguffey]

BIGMAC, I believe it is an exaggeration to say going from 270WSM to 300WSM is case forming. I would say the procedure would be called necking up. If you measure the length of the case before and again after you will notice the case gets shorter and the neck gets longer. I would not suggest you use worked hardened cases, I suggest new and or once fired.

F. Guffey

 

[Homerange]

Would it be wise to go to 7mm (284) as a intermediate step or is this not necessary ?

 

[fguffey]

Would it be wise to go to 7mm (284) as a intermediate step or is this not necessary ?

I have formed 338/06 and 35 Whelen cases from 270 W and 280 Remington cases, I went straight from 270 and 280 to 338 and 35 Whelen without splitting a neck. The 270W and 280 Remington cases are .041" longer than the 30/06 case. When forming cases the case shortens when necked up and when fire formed. I have had cases shorten .045" when firmed and fired. so, I started with longer cases.

The OP is not necking cases up to 338 or 35 Whelen, I was thinking he had 270 WSM cases, there would not be a disadvantage when using 7MM WSM cases. And then there is annealing.

F. Guffey