How bullet pens are made...

 

The bullet casing is drilled and a 7mm brass tube installed.
The pen blank is rough cut...
...drilled, and fitted with a 7mm brass tube.
The pen blank is turned to match the size of the cartridge, sanded, and finished with 7-9 coats of lacquer.
The pen parts are assembled using a pen press.

 

And finally, the finished product...

 

 

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