Necking 300 saum down to to 7mm saum

[sailhertoo]

Never did this before. What do I need to do it right?

Thanks for any help?

 

[Preacher]

Your only going down .024 so a single trip through a 7mm SAUM FL die will do all that needs done unless the necks are a little thick, and then neck turning will be called for. Also figure that doughnuts will form from the necking down...

 

[sailhertoo]

I'm going to use a Redding comp bushing die for sizeing.

Coulde'nt I just step it down with different bushings insted of full length resizeing as you recommend?

Thanks

 

[Preacher]

Yes you can use the bushings in stepping them down, but remember that a bushing die will not go all the way to the bottom of the necks.
You can try it and see if it will work, if not you'll need a full length die to do it...

 

[sailhertoo]

Thanks Preacher

You ever shoot at Oak Ridge?

 

[TheBlueEyedBear]

Like PREACHER said; count on the proverbial 'doughnut' after you size down the NORMA brass. I learned this with my 6SLR and necking down the LAPUA brass. Something in the air over there where this brass is made.
Best way to solve that is after necking down, use the .001 expander mandrelm then turn the necks with a turner that has a carbide cutter mandrel.
Another step you may want to use is to test the first case you down-size. Neck it down partially then try it in your chamber. Then neck down more and try it in your chamber again. Keep doing this until the brass just fits. Then set your die and do the rest. This should give you perfect brass for your chamber.

 

[Preacher]

"You ever shoot at Oak Ridge?"

Nope, but maybe some day when I'm not recycling groundhogs..

 

[Yellow11]

When reducing neck size for my 7/300 WSM, I found I got a "squarer" neck by first bushing .330" followed by .320" and then finished with FL die.

As already mentioned, just using bushes will not take in the full depth of ther neck.

 

[sailhertoo]

Well I've ended up using a body die to start the neck down, then a .321 bushing in a Redding neck sizer, then a .318 bushing in a Redding full length sizer. Then turn the necks.

My Norma brass starts out very concentric (.001-.002) but after the last too sizings in the redding dies it goes to .004-.005 .

I've swapped bushings and tried running an expander mandril down the neck but I can't get rid of the run out. I'm hoping it will fire form out and I will do one more neck turn and then it will be gone.

 

[Santee116]

The good news is, you soon won't have to neck down .300 brass, as Nosler (Norma) will begin making 7mm SAUM brass in 2011. I heard it should be out around midyear, June - July.

 

[4xforfun]

I have never had much luck using a bushing die to neck down brass.....there seems to be more clearance with a regular (non bushing) FL die....the brass starts into the neck without scraping the brass. I mess up less brass