Advice on "Necking Down"

[JagdBob]

I am new to reloading. Which is better/easier to neck down to 270 WSM, 7mm WSM brass or 300 WSM brass? Or does it matter?

 

[FEENIX]

I am new to reloading. Which is better/easier to neck down to 270 WSM, 7mm WSM brass or 300 WSM brass? Or does it matter?

It does not matter (.024" difference).

 

[sedancowboy]

The 270 WSM and the 300 WSM have the same base to datam line. The only difference is the neck size. The 7mm WSM has a longer base to datam line to prevent it from firing in a 270 WSM so the 300 WSM would be much easier to neck down than the 7 WSM because you would have to also push the shoulder back on the 7 WSM.

 

[JagdBob]

It does not matter (.024" difference).

Thank you for your feedback!

 

[JagdBob]

The 270 WSM and the 300 WSM have the same base to datam line. The only difference is the neck size. The 7mm WSM has a longer base to datam line to prevent it from firing in a 270 WSM so the 300 WSM would be much easier to neck down than the 7 WSM because you would have to also push the shoulder back on the 7 WSM.

Thank you sedancowboy. That was very helpful!

 

[L.Sherm]

The 270 WSM and the 300 WSM have the same base to datam line. The only difference is the neck size. The 7mm WSM has a longer base to datam line to prevent it from firing in a 270 WSM so the 300 WSM would be much easier to neck down than the 7 WSM because you would have to also push the shoulder back on the 7 WSM.

If your pushing the shoulder back aren't you pushing the datum line Too?
If it was me I would neck down 300wsm ADG because of quality. Your not gonna be necking down 270wsm brass anyway for a 7wsm

 

[JagdBob]

Thank you L.Sherm!

 

[sedancowboy]

If your pushing the shoulder back aren't you pushing the datum line Too?
If it was me I would neck down 300wsm ADG because of quality. Your not gonna be necking down 270wsm brass anyway for a 7wsm

Not sure what you are asking. The datum line is simply the center of the shoulder used by SAMMI
for a base to shoulder measurement. The 7 WSM is .038 Longer at the Datum line than a 270 WSM.
So yes if you push the shoulder back then you are pushing the Datum line back as well.
For the OPs benefit it is difficult to push the shoulder back on a Magnum cartridge case.
You are correct that the ADG would be a great choice of brass.

 

[L.Sherm]

Sorry Sedan I got a brain fart going on, I read it wrong assuming o.p was wanting 7wsm brass instead of 270wsm.

 

[sedancowboy]

Sorry Sedan I got a brain fart going on, I read it wrong assuming o.p was wanting 7wsm brass instead of 270wsm.

LOL we all get them at times. All is good friend!