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Discussion Starter #1
I use an RCBS Trim Pro manual case neck trimming kit for "improving" 270 case neck concentricity and thickness uniformity.   Problem is, the pilot/reamer mines the brass from the inside neck wall.  It is hard as #### to advance the pilot into the case.  I have to literally force the reamer to advance.  The outside neck shaver has barely touched a single case.

I suspect 1.) the RCBS case sizing die is overly working the case neck or 2.) the pilot reamer's diameter is too large.

Anyone else have a similar problem and possibly a solution?  I am certain it should not be mining so much of the brass away and I am additionally certain it should not be so difficult to advance the pilot/reamer.
 

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Landowner,

I too have had this problem and quickly found out that the best solution was to trim the brass before it was resized.

If you have quite a few cases sized already and would like to trim them before you fire them,  put your pilot in a 1/4" power drill and use some emery cloth or a stone  to reduce the diameter until it has just a little clearance in the sized case neck.  A file will work ok too if the pilot has not been heat treated.

Good luck,
John
 

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Been there.  The solution that worked best for me was to put away the expander/decap part of the sizing die.  I decap with a universal decap die and then size, followed by neck expanding with either a Lyman "M" die or RCBS equivalent.  Not only does this procedure make the trimming pilot enter and exit the case easier, but also that by expanding the case neck as the case goes into the die instead of when it is being pulled out of the die, that cases need trimming less often.  This has proved to be the case in every single caliber that I load for, and that's a lot.  I am thoroughly convinced that much of case lengthening is caused by the case being pulled back over the expander button on it's way out of the sizing die, as I can find no other explanation for the decrease in frequency of trimming (same load, bullets, seating depth...)
 

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Sinclair International and others make expander mandrels in a variety of sizes to deal with this problem.
Or, you can put your pilot in a drill and emery it down a bit... Both work, but the mandrel is easier and more precise.  :wink:
Tom
 

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BB,

I agree fully with using the M type die to expand case necks rather than the pull through expander ball.

Had a horrendous problem with case necks not concentric with the remaining case body using an expander ball in the sizing die. My Krag cases would exhibit severe neck wobble when rolled across a counter top.

Found that the factory annealing was uneven in the neck/shoulder area causing the ball to distort one side of the neck/shoulder when pulled through.

Switched to an M type expander die and the problem was solved. That's all I use now on all my cases. It's an extra step but it's worth it.


Regards, Ray
 

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to big bore and etc.
 what I did was to lap the neck portion of my resizers so the neck is still at the size it came out of the fire arm then measure for length and use a Lee sizer if I have to.In fact I usually measure for length first and if I dont need to resize, I use aLee mandrel neck sizer. I know, I know on some sites that Lee is a dirty word ,but I have good to excelant results with thier merchandise.
 tbc
 
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