7mm WSM size up .270 or size down .300?

[bwaites]

What to do, what to do?

I want to use Norma brass to improve consistency, but I'm not sure if sizing up .270 WSM brass or sizing down .300 WSM brass is a better option.

Any thoughts or help is appreciated!

Bill

 

[J E Custom]

What to do, what to do?

I want to use Norma brass to improve consistency, but I'm not sure if sizing up .270 WSM brass or sizing down .300 WSM brass is a better option.

Any thoughts or help is appreciated!

Bill

Bill.

I would use the 300 WSM brass if I could not get the 7 WSM brass in the make I wanted.

You could size down the 300 brass and then turn the necks to true them and still have nice
thick necks that are uniformed.

Even the 325 WSM could be used but no matter which one you use you will have to fire
form the brass for the 7 WSM.

J E CUSTOM

 

[bwaites]

Does that increase the risk of the infamous "donut"?

It's what I was thinking, but I've never done it, so wanted some advice!

Bill

 

[J E Custom]

Does that increase the risk of the infamous "donut"?

It's what I was thinking, but I've never done it, so wanted some advice!

Bill

Anytime you neck size up or down you run the risk of ballooning if the necks are not lubed
well. ( I lube inside and out when doing this ).

Even when expanding up you have to force the expander ball down the throat of the neck
risking ballooning . So I use a swab soaked in sizing lube and do all of the cases on the
inside.

Good luck

J E CUSTOM

 

[bwaites]

Thanks, much appreciated!

Bill

 

[MagnumManiac]

Bill.

I would use the 300 WSM brass if I could not get the 7 WSM brass in the make I wanted.

You could size down the 300 brass and then turn the necks to true them and still have nice
thick necks that are uniformed.

Even the 325 WSM could be used but no matter which one you use you will have to fire
form the brass for the 7 WSM.

J E CUSTOM

I don't believe you can neck the others up/down to 7mmWSM due to the shoulder being further forward.
You could neck down from 300WSM brass and leave an auxillary shoulder to headspace off, but that alone can cause problems.
You would have to use a fireforming load, shotgun powder, cream 'o' wheat, and something to plug the case mouth like pumpkin or potato. This may eliminate the donut, but it may not also!
I think it's too much trouble bothering with, IMHO.

 

[geargrinder]

I don't believe you can neck the others up/down to 7mmWSM due to the shoulder being further forward.
You could neck down from 300WSM brass and leave an auxillary shoulder to headspace off, but that alone can cause problems.
You would have to use a fireforming load, shotgun powder, cream 'o' wheat, and something to plug the case mouth like pumpkin or potato. This may eliminate the donut, but it may not also!
I think it's too much trouble bothering with, IMHO.

I'll disagree. I've done both with excellent results. I've necked up with 270 and necked down with 300.

With the 270 brass, I just jammed the VLD a little into the lands and used a mid range powder load. Perfect fireforms and accurate loads.

With the 300 brass, I left the false shoulder and used the same load and OAL. Yes, the necks were a little thicker, but were not an issue in my chamber.

Definitely worth the trouble. The Norma brass is way better, makes the Win and Rem brass look like junk.

 

[mo]

I neck up up the 270wsm norma brass to 30 cal. then back down to 7mm. I do this to create a shoulder.

 

[geargrinder]

I neck up up the 270wsm norma brass to 30 cal. then back down to 7mm. I do this to create a shoulder.

Yep, done that too. That's when I tried to just shoot them with a jammed bullet. That worked so I decided it was just working the brass more than needed.