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Hensley & Gibbs 503S, 503SX .44 Mould Comparison

The .44 “Keith” Semi-Wadcutter

© 2014 – Thomas C. Dugas

I acquired a new style of #503, a 503SX 4 cavity mould.  It's a late production mould (thick handles (.308”), with serial number).  I have surmised that the design is the Keith .44 bullet, (503) heavy ("S" @ ~290 grains) with an eXperimental change to a thicker front driving band and shorter extended base.  This experimental design appears to move more of the bullet weight outside of the case.

The Hensley & Gibbs factory ledger entry for the original Keity design #503:

#503-.44 Caliber. 250 grains. "Keith style", designed by Elmer Keith. Plain base, one square grease groove, one heavy crimp groove, semi-wadcutter shoulder, gently rounded nose taper, to slightly rounded meplat.

The photos are descriptions are for those interested in the Keith designs.  For comparative purposes, I included photos of a "standard" 503S combo mould, which is a 4 cavity mould that has two different cavity styles, two cavities are the standard 503 design, and two are the 503S extended base design which brings the weight up to around ~290 grains.  Note that in the combo mould, the front driving band is noticeably thinner than in the 503SX mould.  For more information on the Hensley & Gibbs Mould numbering scheme, click here for an article on that subject.

I invite comments regarding the designs and the intent behind the 503SX design change.

The photos:

First....the original 503S combo 4 cavity mould:

And for comparison, the newly acquired 503SX 4 cavity mould with the thicker front driving band and shorter extended base:

Click on Photos for larger pic

The three projectile designs side by side for comparison and labeled:

The same photo, as a hyperlink, without any labels:

The three different cavity designs side by side for comparative purposes:

Both Moulds side by side for comparison…

And the edge delineation for the profiles.  Notice the 2X denser venting on the 503SX, I would guess that is also part of the eXperimentation.  Easy to see the larger driving band on the 503SX:




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