Time for an update.
First up, counting the ammo down...
A rare earth magnet on VHB taped to the slide and a Hall effect sensor and comparator to drive the Cortex. The sensor is a bit hard to make out, looking like a super slim transistor.
A quick aside. The yellow filler primer is showing through in some of these photos, so I've gone over with some black acrylic and will be sealing the finished piece to avoid this wear. I could really do with finding some black and maybe some grey filler primers in the UK. The yellow stuff from Halfords is probably fine when used for automotive repairs, but most props will be taking a much thinner build up of paint than I would use for a car.
The slide tail piece I had to reshape in Meshmixer. There was no way to get the original to fit the slide without basically hogging away and rebuilding with epoxy putty or similar. No fun in that when I can do it in software. The hex screw you can see is what holds it onto the slide. I actually modelled a replacement back cap for the G17 slide. It has a countersunk hole at a useful angle to grab the main body of the tail piece. A nice, two part solution.
The tail piece in place. Annoyingly the top part is wrong, the rectangular section should be recessed rather than flush.
I had intended to print the name plate on the Form 1+ but it was a complete failure. The Form 1+ peel mechanism is far less reliable than the Form 2 it seems. So I decided to try printing at high res on the S5, after modelling the plate again from scratch, this time with a void to take a switch and wiring. The little dirty brown button is visible on the lower part of the plate, in front of the dummy front-mag release button.
The S5 did a great job with the text. Not perfect, but better than the lumpy resin soup that the Form "printed".
The barrel and top covers I've tried to slightly metallicize with the lightest touch of RubnBuff. It looks better in daylight than the flash here, but I will also be revisiting the finish. I intend to do a full weathering treatment before I'm done, so there will be much more "metal scuff" detailing to provide the right contrast which is lacking at present.
Next up, swapping over to the blue screen, thanks to Joatrash for making my mind up to go blue.