Author Topic: Expander Die Diameter for the .45 ACP  (Read 8656 times)

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ARTINCT

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Expander Die Diameter for the .45 ACP
« on: January 17, 2010, 02:43:45 pm »
Hi Guys:

If you have a Star with a .45 ACP tool head or die set, can you please do me a favor?

Please measure your expander/belling die and report back here with what your diameter is of the longer neck (not the tappered bell section) that expands the 45 ACP case neck.?

I have two such dies and one .449" and the other is .4475"

BTW, a smaller expander means more neck tension imparted to the bullet and a larger expander means less neck tension.

When taking your reading of a die on an installed machine head, please make sure the caliper is 100%
perpendicular to the die or you will possibly get a larger reading.  Also please use a heavy hand on your
caliper as far as jaw tension is concerned.

I was just wondering if STAR sold variants of this which could impart different bullet tension?

Neither of these dies indicates any pedigree as to their original manufacturer however both are
a part of Lifetime sets...

So I would be interested in what sizes are out there...
« Last Edit: January 18, 2010, 06:45:18 am by ARTINCT »
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Manuel

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Re: Expander Die Diameter for the .45 ACP
« Reply #1 on: January 17, 2010, 08:22:21 pm »
Let's make sure I'm measuring the part you need.  You are asking about the expander mandrel for 45 ACP, the expander portion, not the bell portion.  I measure .4517 inch.  This is from the expander that came with my Star that was factory setup for loading 45 ACP. This measurement makes sense in that the diamerter of most jacketed 45 ACP bullets is .451 and most cast or lead 45 ACP are .452 (or in my case cast are sized to .4515 for use in a Douglas barrel). 

Hope this helps.  Of course, if I measured the wrong part, let me know and I'll try again!


Manuel

ARTINCT

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Re: Expander Die Diameter for the .45 ACP
« Reply #2 on: January 17, 2010, 10:47:53 pm »
Hi Manuel:
You did measure the correct die.  It is the die in position #2 after the full length sizing die.  This is the die that indeed does the neck expansion and then at the bottom of the lever pull when the machine head is nearing the lowest point, this die is fully inserted into the 45 case and then expands or slightly bells the case mouth.

This then is the key die for neck tension on the bullet.  I have always suspected there were various diameters of this die for different bullet types and powders requiring more tension.

So far we have three data points and each differs... so it is safe to assume there are or were quite a few diameters made.

Any others?
« Last Edit: January 18, 2010, 06:39:06 am by ARTINCT »
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ARTINCT

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Re: Expander Die Diameter for the .45 ACP
« Reply #3 on: January 18, 2010, 06:42:00 am »
Hi Guys:

If you have a Star with a .45 ACP tool head or die set, can you please do me a favor?

Please measure your expander/belling die and report back here with what your diameter is of the longer neck (not the tappered bell section) that expands the 45 ACP case neck.?

I have two such dies and one .449" and the other is .4475"

Care must be taken when measuring this die with a dial caliper if the die is on the machine head.  If the
calipers are not 100% perpendicular with the die then you will get a much larger reading.  Also please
really heavy hand your caliper for compression (in other words not light tension on the jaws).

I was just wondering if STAR sold variants of this which could impart different bullet tension?

Neither of these dies indicates any pedigree as to their original manufacturer however both are
a part of Lifetime sets...

So I would be interested in what sizes are out there...
Art In Connecticut

rbwillnj

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Re: Expander Die Diameter for the .45 ACP
« Reply #4 on: January 18, 2010, 07:31:32 am »
I get .4516 with mine.  The measurement was taken just below the belling portion of the expander.   Note that the expander is slighly tapered, so the reslults of the measurement will depend upon exactly where it is taken.  
« Last Edit: January 18, 2010, 11:25:55 am by rbwillnj »
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ARTINCT

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Re: Expander Die Diameter for the .45 ACP
« Reply #5 on: January 18, 2010, 10:45:07 am »
RBwillJ:
You bring up a wonderful point, that the die is tapered... I did not realize that.  Jeepers that fact makes the measuring a REAL nightmare for data collection.  I will have to rethink this...
Art In Connecticut