This started life as a cheap Denix reproduction of a SMLE bolt action rifle (Britian's WW1 rifle), but the metal parts are cheap pot metal and I managed to snap the tail of the bolt through just moderate normal use.... so I turned it into a prop sci-fi gun instead with Fusion 360! 3D printed the barrel fins, sights, bayonet, and designed the whole new magazine there. Inside it is a 2000mAh LiPo running a series of small LED panels (meant to be backlights for small LCD displays). Running off the battery they should go for about 22H of straight operation, plenty to get through a day of shooting or a convention.
In order to complete this project, electronics and all, you will need:
I recommend printing in PETG or ABS for durability and heat resistance. Some parts of my rifle such as the rear sight and barrel fins were printed in SLA on an EPAX X1, but be careful as resin can be brittle. I did accidentally break my first rear sight.
The Electronics all go inside the magazine.
The battery has a slot for it built into the magazine well adapter, and can be fitted inside using velcro or other adhesives.
The LED panels are designed to sit inside their respective cutouts with the pins bent around in the notches of the threading. If you cannot thread the front of the magazine all the way closed once you've glued the LED panels in place, don't worry, thread it down as far as it will comfortably go, and then cut a section of cloth or place an O-Ring to fill the remaining gap between the cap and the core, it will look fine. I ended up using some black pleather to fill this gap.
The whole magazine should be glued together except for the front cap, which is threaded to allow you access to charge the battery and/or make repairs.
Spray painting should be fairly straight forward. I grabbed some Rustoleum Primer+Paint cans that said they were good for plastic and metal, and disassembled my Denix rifle. I carefully wrapped all the wood in masking tape, and then sprayed gunmetal over most of the parts, with the exception of the barrel band, the nose cap, the magazine core, the rear sight, and the sight wings which I sprayed a rose-golden brass colour.
Remember to always do several thing coats, rather than single thick coats which will drip and puddle.
To weather the gun I simply dry brushed some steel paint along the edges to create scratches and scrapes, and then applied some dark washes with thinned down acrylic once the gun was reassembled.
To add to the backstory of the prop and add more detail, I created a cheekpad on the stock with self-adhesive gauze from my local pharmacy. I then dipped my hand in some red acrylic and created a bloody handprint and some bloody stains in the gauze, before adding the dusty dirt effect using some earth-toned eyeshadow. You can weather using real dirt or other methods, but the eyeshadow goes on really well, gives you a variety of colours, and is hygenic when applied.
The last detail I added was to carve some kill tallies into the wood with a knife. This, of course, is destructive, but I think adds to the character of the gun.