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KLR

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Anyone try to hydroform 6mm Mongoose brass?  I've been experimenting with my 7mm TCU dies and I think it will work. 

I made a plug to make a solid shell holder and then found a drill bit about .002" smaller than my neck I.D. Then I resized a piece of .223 brass in the TCU die,  filled the case with water, ran it back up into the die (sans expander ball), inserted the drill bit, and gave it a few whacks. (I inserted the drill bit upside down and put a piece of brass over the point to protect it and my hammer.)  

Shoulder diameter is .365".

So why couldn't hydroforming with 6mm TCU dies work to convert brass? How close are the Mongoose and 6mm TCU dimensions? From what I've read, the TCU is a little longer from base to shoulder? 


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jnfarra

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Reply with quote  #2 
I think Bruce and co were having good luck forming to normal and then running through a slightly modified 223 trim die and it push the little wrinkle out
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KLR

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Reply with quote  #3 
Quote:
Originally Posted by jnfarra
I think Bruce and co were having good luck forming to normal and then running through a slightly modified 223 trim die and it push the little wrinkle out

I'm trying to avoid the fireforming route and would like to end up closer to the final powder capacity/case dimensions.
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Rifter

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Reply with quote  #4 
Quote:
Originally Posted by KLR
I'm trying to avoid the fireforming route and would like to end up closer to the final powder capacity/case dimensions.

You can't avoid it completely.  Hydroforming is for moving the shoulder toward the neck on the parent case.  But you can't apply enough pressure to fully form things by that method.  It still takes a fireforming load to fill out the shoulder and form clean angles.

The advantage to hydro is that you don't have to fool with creating a a false shoulder to control headspace, or seat a bullet into the lands to do it either.  It eliminates a couple of steps, but doesn't entirely eliminate fireforming from the process.

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RIGGS68

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Reply with quote  #5 
Why not make a similar adapter for your Mongoose die instead of going the 6 TCU route? 
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KLR

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Reply with quote  #6 
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Originally Posted by RIGGS68
Why not make a similar adapter for your Mongoose die instead of going the 6 TCU route? 


The only thing modified is the shell holder. It will work with any die.

But the reason for using a 6 TCU is financial. I'd rather experiment with crusty, used  $25 TCU dies than the $80 Mongoose dies.
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