Neck Die Bushing Info Needed

[Hank]

I am going to buy a seating die that will accept bushings for my 6mmBR..Lothar Walther factory barrel..

The fired brass measures .2675, a loaded round using my old,and sold) Forster seating die measures .2685...

I have read that when selecting a bushing, you should "measure a loaded round at the neck and and select a bushing based on that. But, it seems that I should use the fired brass measurement and then select a bushing to vary the bullet tension..

Am I missing something here or what..???

 

[Forum Boss]

Do you mean your fired,but unloaded) brass measures .2675" AFTER sizing?

Otherwise it does not make sense that a fired case's neck diameter would be LESS than that of a loaded round.

Suggest you measure your loaded round again, double-check your numbers, then pick a bushing that is .002" under the loaded neck diameter. After springback this should give you about .0015" tension. That's a good place to start with the 6BR. Some folks like more tension, some like less.

 

[savet06]

Lynn,
Would that not give you less tension? I am still learning about this stuff so please bear with me. I am in the same position with the rifle I am building. I am planning on using a bushing type die and am wondering which size is best,Mine is a 30br with a .330neck). I don't have a fired round yet, but want all the information once I have the need to purchase. Not looking to highjack, just looking for clarity.
Thanks,
Mike

 

[dreever]

For my .269 neck 6BR my loaded rounds measure .2675 so I use a .265 bushing.

Danny

 

[savet06]

thanks, Lynn.
Makes much more sense. Thanks a bunch for the info.
Mike