Necking Norma .340 Brass to .308(BAER)?????


Well-Known Member
Dec 25, 2001
Central Washington.
Now I have necked down .284 Win brass for a 6.5-284,But the 6.5-284 had a standard chamber and it only took one pass through the redding Comp die(6.5-284) to complete the task.But now that I am sizeing down a Norma .340 Weatherby case to .30 cal.I'm wondering if I should neck it down in steps use several bushings in the Redding Comp die to complete the task.Since this is my first go around with a tight neck cartridge I will let you know how I have thought about going at this and you guys can let me know if I'm going in the right direction.
My Baer has a .336 neck,Once I have necked it down to .30 Cal I planned on turning the necks down to .333 overall or .0015 claerance all the way around then neck sizeing it agian with the Redding Comp die useing a bushing .003 smaller than the neck diameter of a loaded cartridge for proper bullet tension..Please let me know if I am on the right track here...:)....

Landon M
I always size the 340 brass down once with a RCBS full length sizing die that has the neck lapped out to .332" and use an expander that just expands the neck about .001" then I use a pilot slightly smaller than the dia of the exp ball (about .0005") on the neck turner. I turn my necks .013" on a side (wall thickness) for my .336" neck chambers. After I turn my necks I resize the neck with a Redding Bushing Die and a .330" bushing and trim, then do all the other prepping. I always use a near maximum 300 Wby form load seated just touching the lands. Sometimes I turn the necks without sizing them down to 30 cal but when they are sized down the neck will collect brass and give you a better turn (cut). There are other ways also but this works for me.


Instead of using the 300 Wby FL sizing die first (you might not have one), use your Redding Bushing Die with a .332" bushing and the exp that comes with it (if your Redding die has one), if not you should use some sort of provision to expand and make sure your pilot on neck turning tool is the same size or slightly smaller. You can also not use an expander just the bushings but the expander system works well for me.


The guy on the other forum is correct about the Redding Bushing Dies only sizing part of the neck, mine size all the neck-I had them cut out. Also you mentioned turning your necks to .0125" which would be fine, I turn mine to .013" just a little closer. I use a wall tubing micrometer by Mitutoyo that reads in ten thousandths which works well. When your done loading the cartridge just make sure a .335" sizing bushing drops over the neck and you're ready to go.

Warning! This thread is more than 23 years ago old.
It's likely that no further discussion is required, in which case we recommend starting a new thread. If however you feel your response is required you can still do so.